756 resultados para net photosynthesis rate


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We show here that CO2 partial pressure (pCO2) and temperature significantly interact on coral physiology. The effects of increased pCO2 and temperature on photosynthesis, respiration and calcification rates were investigated in the scleractinian coral Stylophora pistillata. Cuttings were exposed to temperatures of 25°C or 28°C and to pCO2 values of ca. 460 or 760 muatm for 5 weeks. The contents of chlorophyll c2 and protein remained constant throughout the experiment, while the chlorophyll a content was significantly affected by temperature, and was higher under the 'high-temperature-high-pCO2' condition. The cell-specific density was higher at 'high pCO2' than at 'normal pCO2' (1.7 vs. 1.4). The net photosynthesis normalized per unit protein was affected by both temperature and pCO2, whereas respiration was not affected by the treatments. Calcification decreased by 50% when temperature and pCO2 were both elevated. Calcification under normal temperature did not change in response to an increased pCO2. This is not in agreement with numerous published papers that describe a negative relationship between marine calcification and CO2. The confounding effect of temperature has the potential to explain a large portion of the variability of the relationship between calcification and pCO2 reported in the literature, and warrants a re-evaluation of the projected decrease of marine calcification by the year 2100.

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以中国东北森林 - 草原样带(NECT)上的松嫩平原羊草草甸草原为研究对象,从影响羊草叶片光合作用的机理出发,基于羊草片光合生理生态特性、羊草群落小气候梯度以及羊草群落生物量等的野外动态观测,分析了羊草叶片的光合生理特性动态特征,建立了羊草叶片的光合作用机理模型,通过尺度化,发展了基于叶片生理特性的羊草群落生产力动态模型;并结合著名的草地生态系统模型—CENTURY模型探讨了人类活动和气候变化对羊草草地的影响。主要结果如下: (1) 晴朗天气下羊草叶片气孔导度和净光合速率日变化均呈双峰型曲线。 (2) 影响羊草叶片气孔导度的主要环境因子是光合有效辐射、叶片与空气间的水汽压亏损以及空气温度。 (3) 影响羊草叶片净光合速率的主要因子是胞间CO2浓度、气孔导度、空气CO2浓度及蒸腾速率。 (4) 对当前2类代表性气孔导度模型的验证表明,基于Jarvis模型所改建的气孔导度模型比依据Leuning改进的Ball模型所建立的气孔导度模型具有更好的模拟效果,并据此建立了适于羊草叶片的气孔导度模型: gs = PAR (-2.01Ta2 + 147.74Ta - 2321.11)/((444.62 + PAR) (-538.042 + VPD)) (5) 结合能量平衡方程和光合作用生化模型,建立了能够模拟羊草叶片CO2、水汽和热量交换的羊草叶片光合作用耦合模型。该模型有能力预测复杂的环境变化对羊草叶片净光合作用和气孔导度的影响。 (6) 通过尺度化(采用多层模式模拟冠层导度,大叶模式模拟光合作用),建立了羊草群落光合作用模型,结合植物群落的呼吸模型,估算了羊草群落的净第一性生产力,并与实测值及CENTURY模型模拟值进行了比较,结果表明,基于叶片光合机理的群落生产力模型较CENTURY模型能更好地反映羊草群落的生产力动态。 (7) 基于CENTURY模型对人类活动、气候变化对羊草草原可能影响的模拟表明,人类活动(割草和放牧)和气候变化都会明显影响羊草草原,但人类活动产生的影响更为显著,尤其是重牧将造成羊草草原土壤有机碳和群落生物量显著降低。因此,制定合理的放牧和割草措施对于维持草场的可持续发展具有重要意义。

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由于人类活动所引起的地球大气层中温室气体的富集已导致全球地表平均温度在20世纪升高了0.6 ℃,并预测在本世纪将上升1.4-5.8 ℃。气候变暖对陆地植物和生态系统影响深远,并已成为全球变化研究的重要议题。高海拔、高纬度地带的生态系统对气候变化最敏感。而在高原和高山极端环境影响下所形成的高寒草甸生态系统极其脆弱,对由于温室效应引起的全球气候变化极其敏感,对这些变化的响应更具有超前性。 本研究以川西北高寒草甸植物群落及几种主要物种为研究对象,采用国际山地综合研究中心(ITEX)普遍所采用的增温方法-----开顶式生长室(OTC)模拟气候变暖来研究增温对高寒草甸植物群落结构、物质分配及其主要物种生长和生理的影响,以探讨高寒草甸植物响应与适应气候变暖的生物学和生态学机制。主要研究结论如下: 1、OTC的增温效果 由于地温、地表温度和气温的平均值在OTC内分别高出对照样地0.28℃、0.46℃和1.4℃,这说明本研究所采用的开顶式生长室(OTC)起到了增温的作用;同时,由于温室内与温室外接受的降水量相同,温室内由于热量条件的改善,土壤蒸发和植被的蒸腾作用增强,直接导致了OTC内土壤表层相对湿度的减少。 2、群落结构对增温的响应 由于增温时间较短,增温内外样地的物种组成并未发生改变;但增温后一定程度上改变了植物群落的小气候环境,从而导致物种间的竞争关系被破坏,种间竞争关系的破坏引起群落优势种组成发生相应的改变,在对照样地,鹅绒委陵菜、甘青老鹳草、遏蓝菜和蚤缀是占绝对优势的物种,而在OTC内,小米草、尼泊尔酸模、垂穗披碱草、发草和羊茅的重要性显著增加。 禾草和杂草由于对增温的生物学特性及其资源利用响应的不同,加之增温造成土壤含水量下降等环境因子的改变。与对照样地相比较,OTC内禾草的盖度及生物量都显著增加,而杂草的盖度和生物量则显著下降。 3、植物生长期对增温的响应 OTC内立枯和调落物的生物量在生长季末(10月份)都要小于对照样地的立枯和调落物生物量,而OTC内的地上鲜体生物量在10月份却略高于对照样地。这说明OTC内植物的衰老或死亡得以延缓,而植物的生长期得以延长。 4、群落生物量及分配对增温的响应 OTC内的地上鲜体生物量(10月份除外)和地下0-30cm的根系生物量与对照样地相比较,都出现了不同程度的减少;土壤根系的分配格局也发生了明显的改变,其中,OTC内0-10cm土层的生物量分配比例增加,而20-30cm土层生物量分配比例的减少。 5、群落碳、氮对增温的响应 增温后,OTC内植物群落地上活体和地下活根的碳浓度不同程度的高于对照样地,植物群落的碳库在OTC内也略高于对照样地;而OTC内植物群落地上活体和地下活根的氮浓度不同程度的低于对照样地,其植物群落的氮库与对照样地相比也略有下降。 6、几种主要植物的生长及物质分配对增温的响应 垂穗披碱草在增温后株高、比叶面积和地上生物量均显著地增加;尼泊尔酸模在增温后比叶面积和单株平均生物量积累显著地增加,而各组分中,增温处理使叶的生物量显著增加,而根的生物量却显著下降;鹅绒委陵菜在增温后株高、比叶面积和单株平均生物量积累显著地减少,而各组分中,增温处理使叶和茎的生物量显著减少,根的生物量却显著地增加。 尼泊尔酸模的LMR、RMR、R/S、根部碳含量、碳和氮在叶片与根部的分配比例在增温后显著地增加,而SMR、根部氮含量、碳和氮在茎部的分配比例在增温后却显著地降低;鹅绒委陵菜的RMR、R/S、碳和氮在根部的分配比例在增温后显著地增加,而SMR、LMR、碳在叶片的分配比例在增温后却显著地降低 7、几种主要植物的光合生理过程对增温的响应 增温使垂穗披碱草和尼泊尔酸模叶片中的叶绿素a、叶绿素b、总叶绿素含量显著增加;而鹅绒委陵菜叶片的叶绿素a、叶绿素b、总叶绿素含量在增温后显著减少,类胡萝卜素含量在增温后却显著增加。 增温对3种植物的气体交换产生了显著影响。其中,垂穗披碱草和尼泊尔酸模叶片的光响应曲线在增温后明显高于对照处理,A、E、gs、Pmax、、Rday、AQY和LSP显著增加,而LCP则显著降低;鹅绒委陵菜的光响应曲线在增温后则明显的低于对照处理,A、E、gs、Pmax、、Rday、AQY和LSP显著减少,而LCP则显著增加。 增温后垂穗披碱草和尼泊尔酸模叶片的Fv/Fm、Yield和qP显著增加;而鹅绒委陵菜叶片的Fv/Fm、Yield和qP则显著减少,qN却显著地增加。 8、几种主要植物的抗氧化酶系统对增温的响应 增温使垂穗披碱草和尼泊尔酸模体内抗氧化酶活性和非酶促作用有所提高,植物膜脂过氧化作用降低;鹅绒委陵菜叶片中酶促反应和非酶促反应在增温后也显著提高,但可能由于增温后的土壤干旱超过了鹅绒委陵菜叶的抗氧化保护能力,抗氧化酶活性及非酶促反应(脯氨酸、类胡萝卜素)的提高不足以完全清除干旱诱导形成的过量活性氧,因此叶片的膜脂过氧化程度仍然显著提高。 Enrichment of atmospheric greenhouse gases resulted from human activities such as fossil fuel burning and deforestation has increased global mean temperature by 0.6 ℃ in the 20th century and is predicted to increase in this century by 1.4-5.8 ℃. The global warming will have profound, long-term impacts on terrestrial plants and ecosystems. The ecoologcial consequences arising from global warming have also become the very important issuses of global change research. The terrestrial habitats of high-elevation and high-latitude ecosystems are regarded as the most sensitive to changing climate. The alpine meadow ecosystme, which resulted from the composite effects of mountain extreme climatic factors in Tibetan Plateau, is thus thought to be especially vulnerable and sensitive to global warming. In this paper, the response of plant community and several main species in the alpine meadow of Northewst Sichuan to experimemtal warming was studied by using open-top chambers (OTC). The aim of the this study was to research the warming effects on plant community structure, substance allocation, growth and physiological processes of several mian species, and to explore the biological and ecological mechanism of how the alpine meadow plants acclimate and adapt to future global warming. The results were as follows: 1. Warming effects of OTC The mean soil temperature, soil surface temperature and air temperature in OTC manipulation increased by 0.28℃、0.46℃ and 1.4℃ compared to the control during the growing season. This suggested that the OTC used in our study had increased temperature there. Meanwhile, the OTC manipulation slightly altered thermal conditions, but the same amount of precipitation was supplied to both the OTC manipulation and the control, so higher soil evaporation and plant transpiration in OTC manipulation directly lead to the decrease of soil surface water content. 2. The reponse of community structure to experimental warming The species richness was not changed by the short-term effect of OTC manipulation. However, experimental warming changed the microenvironment of plant community, therefore competitive balances among species were shift, leading to changes in species dominance. In the present study, the dominant plant species in the control plots were some forbs including Potentilla anserine, Geranium pylzowianum, Thlaspi arvense and Arenaria serpyllifolia, however, the importance value of some gramineous grasses including Elymus nutans, Deschampsia caespitosa, Festuca ovina, and some forbs including Euphrasia tatarica and Rumex acetosa significantly increased in OTC. The different biology characteristics and resource utilizations between gramineous grasses and forbs, and enhanced temperature caused change in some environment factors such as soil water content. As a result, the coverage and biomass of gramineous grasses significantly increased in OTC compared to the control, however, the coverage and biomass of forbs singnifciantly decreased in OTC compared to the control. 3. The reponse of plant growing season to experimental warming Both the standing dead and fallen litter biomass in OTC were lower than those in the control in October, and the biomass of aboveground live-vegetation in OTC was higher than that of the control. The results indicated that the senescence of plants was postponed, and the growing season was prolonged in our research. 4. The reponse of community biomass accumulation and its allocation to experimental warming Experimental warming caused the decrease of aboveground live biomass and belowground root biomass except for the aboveground live biomass in October. Experimental warming also had pronounced effects on the pattern of root biomass allocation. In the present study, the root biomass in 0-10cm soil layer increased in OTC manipulation compared to the control, however, the root biomass in the 20-30cm soil layer decreased in OTC manipulation compared to the control. 5. The reponse of community C and N content to experimental warming The C concentration and stock in aboveground live and belowground root both increased in OTC manipulation compared to the control. However, the N concentration and stock in aboveground live and belowground root both decreased in OTC manipulation compared to the control. 6. The reponse of gowth and biomass, C and N alloction of several species to experimental warming Experimental warming significantly increased the height, SLA (specific leaf area) and aboveground biomass of Elymus nutans in OTC manipulation compared to the control. The SLA and total biomass of Rumex acetosa also significantly increased in OTC manipulation compared to control, among the different components of Rumex acetosa, leaf biomass significantly increased, but root biomass significantly decreased in OTC manipulation compared to the control. However, the height, SLA and total biomass of Potentilla anserina significantly decreased in OTC manipulation compared to the control, among the different component of Potentilla anserina, leaf and stem biomass significantly decreased, but root biomass significantly increased in OTC manipulation compared to the control. The LMR (leaf mass ratio), RMR (root mass ratio), R/S (shoot/root biomass ration) and root C concentration of Rumex acetosa significantly increased in OTC manipulation compared to outside control, also, Rumex acetosa allocated relatively more C and N content to leaf and root in response to experimental warming, however, the SMR (stem mass ration) and root N concentration of Rumex acetosa significantly decreased in OTC manipulation compared to outside control, also, Rumex acetosa allocated relatively less C and N content to stem in response to experimental warming. The RMR and R/S of Potentilla anserina significantly increased in OTC manipulation compared to outside control, also, Potentilla anserina allocated relatively more C and N content to root in response to experimental warming, however, the SMR and LMR of Potentilla anserina significantly decreased in OTC manipulation compared to outside control, also, Potentilla anserina allocated relatively less C and N content to leaf in response to experimental warming. 7. The reponse of physiological processes of several species to experimental warming Experimental warming significantly increased chlorophyll a, chlorophyll b and total chlorophyll of Elymus nutans and Rumex acetosa in OTC manipulation compared to outside control. However, chlorophyll a, chlorophyll b, total chlorophyll and carotenoid of Potentilla anserina in OTC manipulation significantly decreased compared to outside control. Experimental warming had pronounced effects on gas exchange of Elymus nutans, Rumex acetosa and Potentilla anserine. In the present study, warming markedly increased the light response curves of Elymus nutans and Rumex acetosa in OTC manipulation compared to outside control, and also singnificantly increased A (net photosynthesis rate), E (transpiration rate), gs (stomatal conductance), Pmax (maximum net photosynthetic rate), Rday (dark respiration rate), AQY (apparent quantum yield) and LSP (light saturation point), but LCP (photosynthetic light compensation) of Elymus nutans and Rumex acetosa in OTC manipulation singnificantly decreased compared to outside control. However, warming markedly decreased the light response curves of Potentilla anserina in OTC manipulation compared to outside control, and also singnificantly decreased A, E, gs, Pmax, Rday, AQY and LSP, but LCP of Potentilla anserina in OTC manipulation singnificantly increased compared to outside control. Experimental warming singnificantly increased the chlorophyll fluorescence kinetics parameters such as Fv/Fm, Yield and qP of Elymus nutans and Rumex acetosa and qN of Potentilla anserina in OTC manipulation, but Fv/Fm, Yield and qP of Potentilla anserina in OTC manipulation singnificantly decreased. 8. The reponse of antioxidative systems of several species to experimental warming Experimental warming tended to increase the activities of antioxidative enzymes and stimulate the role of non-enzymes of Elymus nutans and Rumex acetosa. As a result, MDA content of Elymus nutans and Rumex acetosa decreased. The activities of antioxidative enzymes and non-enzymes of Potentilla anserina also significantly increased in OTC manipulation, but more O2- was produced because of lower soil water content, and the O2- accumulation exceeded the defense ability of antioxidative systems and non-enzymes fuctions. As a result, MDA content of Potentilla anserine still increased in OTC manipulation compared to outside control.

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干旱胁迫是全球范围内影响植物生存、生长和分布的重要环境因子。岷江上游干旱河谷区,由于生态环境的脆弱性和长期人类活动的干扰和过度利用,导致植被严重退化,水土流失加剧,山地灾害频繁,干旱化和荒漠化趋势明显。这种趋势若不能遏制,将严重阻碍区域社会经济的快速协调发展,并且威胁成都平原地区的发展和长江中下游地区的生态安全。因而开展干旱河谷生态恢复研究成为解决这些问题的关键。水分匮乏是限制干旱河谷生态恢复的关键因子,在全球气候变化的背景下,干旱胁迫在区域尺度上可能会更加严重,并使干旱河谷的生态环境更加恶化。因此,深入研究干旱河谷乡土植物对干旱胁迫的响应和适应机理,具有非常重要的理论和实践意义。 本论文以岷江上游干旱河谷的三种乡土豆科灌木,白刺花(Sophora davidii)、小马鞍羊蹄甲(Bauhinia faberi var. microphylla)和小雀花(Campylotropics polyantha)理论和实践意义。为研究对象,在人工控制条件下设计了4-5个连续性干旱胁迫处理,系统地研究了灌木幼苗的生长、生物量积累和水分利用效率(WUE)、形态结构和生理过程等对干旱胁迫的反应,揭示了幼苗的干旱适应能力及种间差异。主要研究结论如下: 1) 灌木生长和繁殖对干旱胁迫的反应 在干旱胁迫下,幼苗生长速率显著减小,叶片衰老和脱落比率增大,这些变化随着胁迫强度的增加具有累积效应。叶片比茎对干旱胁迫的反应更敏感。在严重干旱胁迫下,幼苗的有性繁殖被限制,但在中等程度干旱胁迫下,幼苗的有性繁殖能力被提高。 2) 灌木生物量积累及其分配和WUE对干旱胁迫的反应 在干旱胁迫下,灌木各器官的生物量都显著减小,但是生物量的分配侧重于地下部分,使得根茎比在干旱条件下增大。幼苗的耗水量(WU)随着干旱胁迫的增加而显著减少。白刺花和小马鞍羊蹄甲WUE在干旱胁迫下降低;小雀花的WUE在中等干旱胁迫下升高。 3) 灌木叶片结构特征对干旱胁迫反应 白刺花叶片具有较为典型的旱生型结构,而小马鞍羊蹄甲和小雀花则为中生型结构。在1至2年的干旱胁迫下,灌木叶片结构组成未发生本质性的改变,主要是细胞大小的变化。在中等和严重干旱胁迫下,叶肉组织厚度明显减小;并且气孔和表皮细胞面积也显著减小,气孔和表皮细胞密度显著增大;叶肉细胞层数、P/S值、表皮厚度等无显著变化。 4) 灌木对干旱胁迫的生理响应 气体交换参数和叶片相对含水量(RWC)在中等干旱胁迫下发生了明显的改变,而叶绿素荧光参数和光合色素含量在严重干旱胁迫下才发生显著变化。在干旱胁迫下,净光合作用速率(Pn)、气孔导度(gs)和RWC呈下降趋势,而叶片温度(Tl)呈增加趋势,蒸腾速率(Tr)的变化不明显。除了日最大Pn减小以外,干旱胁迫对气体交换参数的日变化无显著影响,但是对光合-光响应曲线有显著的影响,使有效光合时间缩短。在严重干旱胁迫下光系统受到损害而代谢减弱,PSⅡ中心的内禀光能转换效率(Fv/Fm)、量子产量(Yield)、光化学淬灭参数(qP)显著降低,而非光化学淬灭参数(NPQ)明显增加。气孔限制和非气孔限制对Pn的影响与干旱胁迫强度有关。在中度胁迫下,气孔限制起主导作用,在严重胁迫下非气孔限制起主导作用,40% FC水分条件可能是灌木由气孔限制向非气孔限制的转折点。 5) 灌木对干旱胁迫的适应能力及其种间差异 三种灌木对干旱胁迫具有较好的适应能力,即使在20% FC,幼苗未因干旱胁迫III而死亡;80% FC适宜于幼苗生长。白刺花生长速率慢,耗水量较少,具有较强的耐旱和耐贫瘠能力,并具有干旱忍受机制,能够在较干旱的环境中定居和生长。小马鞍羊蹄甲和小雀花,生长快,水分消耗量较大,尤其是小雀花,对干旱胁迫的忍受能力较弱,具有干旱回避机制,因而适宜于在较为湿润的生境中生长。综合分析表明,生长速率较慢的物种抗旱能力较强,其更适宜于作为干旱地区植被恢复物种。 Drought is often a key factor limiting plant establishment, growth and distribution inmany regions of the world. The harsh environmental conditions and long-termanthropogenic disturbance had resulted in habitat destruction in the dry valley ofMinjiang river, southwest China. Recently, it tended to be more severe on the vegetationdegradation, soil erosion and water loss, natural disaster, as well as desertification, whichimpact on regional booming economy and harmonious development, and would be verydangerous to the environmental security in the middle and lower reaches of Yangzi River.Therefore, ecological restoration in the dry valley is one of the vital tasks in China. Waterdeficit is known to affect adversely vegetation restoration in this place. Moreover, in thecontext of climate change, an increased frequency of drought stress might occur at aregional scale in the dry valleys of Minjiang River. The selection of appropriate plantingspecies for vegetation restoration in regard to regional conditions is an important issue atpresent and in further. The research on responses of indigenous species to drought stresscould provide insights into the improvement of the vegetation restoration in the dry valleys of Minjiang River. In this paper, the responses of three indigenous leguminous shrubs, Sophora davidii,Bauhinia faberi var. microphylla and Campylotropics polyantha, to various soil watersupplies were studied in order to assess drought tolerance of seedlings, and to compare interspecific differences in seedlings’ responses to drought stress. The results were as follows: 1 Growth and reproduction of shrubs in response to drought stress Seedling growth reduced significantly while leaf senescence accelerated underdrought stress, the cumulative responses to prolonged drought were found. The capacityfor reproduction was limited by severe drought stress, and improved by moderate droughtstress. Leaf responses were more sensitive than shoot to various water supplies. 2 WUE, biomass production and its partitioning of shrubs in response to drought stress Drought stress reduced significantly the total dry mass and their components ofseedlings, and altered more biomass allocation to root system, showing higher R/S ratiounder drought. Water use (WU) and water-use efficiency (WUE) of both S. davidii and B.faberi var. microphylla declined strongly with drought stress. The WU C. polyantha ofalso declined with drought stress, but WUE improved under moderate drought stress. 3 Anatomical characteristics and ultrastructures of leaves in response to drought stress There were xeromorphic for S. davidii leaves and mesomorphic for B. faberi var.microphylla and C. polyantha at the all water supplies. The foundational changes in leafstructures were not found with drought stress. However, mesophyll thickness, the areas ofstomatal and epidermis reduced slightly while the densities of stomatal and epidermisincreased under severe drought stress. Variations in these parameters could mainly be duoto cell size. Other structures did not displayed significant changes with drought stress. 4 Physiological responses of shrubs to drought stress The gas exchange parameters and leaf relative water content (RWC) were affectedby moderate stress, while chlorophyll fluorescence and chlorophyll content were onlyaffected by severe stress. Drought stress decreased net photosynthesis rate (Pn), stomatalconductance, light-use efficiency and RWC, and increased leaf temperature. Therespiration rates (Tr) were kept within a narrower range than Pn, resulting in aprogressively increased instantaneous water use effiecency (WUEi) under drought stress.Moreover, drought stress also affected the response curve of Pn to RAR, there was adepression light saturation point (Lsat) and maximum Pn (Pnmax) for moderate andsevere stressed seedling. However, diurnal changes of gas exchange parameters did notdiffer among water supplies although maximum daily Pn declined under severe stress.VISevere stress reduced Fv/Fm, Yield and qP while increased NPQ and chlorophyll content.Photosynthetic activity decreased during drought stress period due to stomatal andnon-stomatal limitations. The relative contribution of these limitations was associatedwith the severity of stress. The limitation to Pn was caused mainly by stomatal limitationunder moderate drought stress, and by the predominance of non-stomatal limitation undersevere stress. In this case, 40% FC water supply may be a non-stomatal limitation 5 Interspecific differences in drought tolerance of shrubs Three shrubs exhibited good performance throughout the experiment process, evenif at 20% FC treatment there were no any seedlings died, 80% FC water supply wassuitable for their establishment and growth. S. davidii minimized their water loss byreducing total leaf area and growth rate, as well as maintained higher RWC and Pncompared to the other two species under drought stress, thus they might be more tolerantto the drought stress than the other two species. On the contrary, it was found that C.polyantha and B. faberi var. microphylla had higher water loss because of their stomatalconductance and higher leaf area ratios. They reduced water loss with shedding theirleaves and changing leaf orientation under drought stress. Based on their responses, thestudied species could be categorized into two: (1) S. davidii with a tolerance mechanismin response to drought stress; (2) C. polyantha and B. faberi var. microphylla withdrought avoidance mechanism. These results indicated that slow-growing shrub speciesare better adapted to drought stress than intermediate or fast-growing species in present orpredicted drought conditions. Therefore, selecting rapid-growing species might leavethese seedlings relatively at a risk of extreme drought.

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沙棘广泛分布于亚欧大陆的温带地区和亚洲亚热带的高海拔地区。沙棘能适应多种生态环境,能耐受多种逆境(如干旱、低温、高温和盐害等)。在中国,沙棘常常被用作植被恢复中的先锋树种而大量栽培。本文以中国沙棘为试验材料,探索沙棘适应干旱机制,以及沙棘对干旱胁迫的适应机制是否存在种群间的差异,同时试图通过分析干旱胁迫下沙棘叶片蛋白质表达变化探索沙棘适应干旱胁迫的分子机理。 对三个分别来自低海拔湿润地区、低海拔干旱地区和高海拔湿润地区的中国沙棘种群进行干旱胁迫处理。干旱胁迫能提高根冠比,比叶面积,降低平均叶面积和总生物量,提高沙棘的抗氧化性酶活性、脯氨酸含量、脱落酸(ABA)含量、降低光合作用,提高长期用水效率。实验中的这两个低海拔种群比高海拔种群抵抗干旱的能力更强,不同的种群采用了不同的策略来耐受干旱胁迫和过氧化胁迫。 在2004 年度的实验中,干旱胁迫处理下,高海拔湿润种群(道孚种群)严重失水,生长也受到更大的抑制,非气孔因素在抑制光合作用方面占支配地位,抗坏血酸含量下降,ABA和脯氨酸含量增加幅度比九寨沟种群的要高,这可能是因为道孚种群严重失水而引起的;而低海拔湿润种群(九寨沟种群)的体内水分状况几乎不受干旱的影响,生长情况也较道孚种群要好。 在2005 年度的试验中,和高海拔湿润地区种群(道孚)相比较,低海拔干旱地区种群(定西)在叶片相对水含量、根冠比、抗氧化酶活性(过氧化氢酶、抗坏血酸过氧化物酶和谷胱甘肽过氧化物酶)、保护性物质(脯氨酸,脱落酸)含量等方面都要高,光能热耗散能力也更强,而且气体交换参数(气孔扩散阻力和胞间CO2浓度等)对干旱也更不敏感。 分析了干旱胁迫下沙棘叶片蛋白质表达的变化。共发现319 个蛋白质,有4 个蛋白在干旱胁迫下消失(Putative ABCtransporter ATP-binding protein 、Hypothetical proteinXP-515578,热激蛋白Hslu219 和一个没得到鉴定的蛋白),4 个只在干旱胁迫下出现(没命名的蛋白质产物,对甲基苯-丙酮酸双加氧酶,NTrX 和一个没得到鉴定的蛋白),46 个蛋白质的表达丰度变化显著,包括32 个干旱负调蛋白,14 个干旱正调蛋白(3 个Rubisco 的大亚基、J-type–co-chaperone Hsc20、putative protein DSM3645-2335、putative acyl-COA 脱氢酶、nesprin-2 和两个没有得到鉴定的蛋白质)。这些蛋白质参与了氮代谢调控、抗氧化行物质的合成、脂肪酸β-氧化、核骨架构造、[Fe-S]基团组装、物质跨膜运输、细胞分裂或作为分子伴侣和蛋白质酶起作用。putative ABC transporter ATP-binging protein、NtrX、nesprin-2 和Hslu 是本试验新发现的高等植物蛋白,我们主要从它们的保守结构域或在其他生物中的同源物来猜测它们的功能。实验结果为我们研究植物抗干旱机制提供了新线索和新视野。 Seabuckthorn (Hippophae rhamnoides L.) is widly distributed throughtout the temperatureresiogn of Europe and Asia and sub-tropical plateau zone of Asia. H. rhamnoides can adapatseveral different environments, and can tolerant several envioronmental stresses (e.g, lowtemperature, high temperature, drought and salty). It has been widely used in forest restoration asthe pioneer species in China. In present study, we applied H.rhamnoides subsp. Sinensis asexperimental materials to study its drought-tolerant mechanism, and expected to findpopulational difference in drought-tolerant mechanism that may exist among populations, and tryto get some insight in drought-tolerant mechanism of it at morecular level through analyzing thechange of leaf protein expression. Three populations from high altitude wet zone, low altitude wet zone and low altitude arid znoe,respectively, were applied in our experiment, and were subjected to drought. Drought increasedthe root/shoot ratio(RS), special leaf area, long-term water use efficinency, activity of antioxidantenzymes, proline content and abscisic acid (ABA) content, declined the net photosynthesis rate(A), average leaf area (ALA), total biomass (TB). Both two low altitude populations were moredrought-tolerant than the high altitude population, and different population applied differentstratedgies to tolerant oxidant stress and drought stress. The results of the exprement in 2004 showed that Daofu population was more drought-sensitivethan Jiuzhai population. Under drought conditions, leaf relative water content (RWC) greatlydecreased in Daofu population, but not in Jiuzhai population. The large loss of water in Daofupopulation resulted in a limitation on A mainly caused by non-stomatal factors, severer suppression in growth rate and a significant reduction in ascorbic acid (AsA) content, comparedwith Jiuzhai population. The greater increase in content of ABA and proline in Daofu populationmay be also induced by large loss in water, so that enable plants to cope with sever drought. In the exprement of 2005, drought significantly increased RS, activities of catalase (CAT),peroxidase (POD), glutathione peroxidase (GPX) and ascorbate peroxidase (APX), and alsosignificantly increased ABA and proline contents. On the other hand, compared with Daofupopulation, drought induced larger RS and activities of CAT, GPX and APX, and higher ABAcontent in Dingxi population, whereas gas exchange traits, e.g., stomatal limitation value (LS) andintercellular CO2 concentration (Ci), were less responsive to drought in Dingxi population thanthose in Daofu population. All these factors enable Dingxi population to tolerant drought betterthan Daofu population. The leaf protein profile of seabuchthorn subjected to drought was analyzed. Altogether 319proteins were detected in well-watered sample, four proteins disappeard by drought (putativeABCtransporter ATP-binding protein, hypothetical protein XP-515578, Hslu219and aunidentified protein), four only appeared under drought (a probable nitrogen regulation protein(NtrX), a 4-hydroxyphenylpyruvate dioxygenase , an unnamed protein product and an identified protein), 32 drought down-regulated proteins, and 14 drought up-regulated proteins (nine wereidentified: three large subunits of Rubisco, a hypothetical protein DSM3645-23351, a putativeacyl-COA dehydrogenase, a nesprin-2, a J-type-co-chaperone HSC20 and two unmatchedproteins). These proteins may involve in β-oxidation, cross-membrane transport, cell division,cytoskeleton stabilization, iron-sulfur cluster assembly, nitrogen metabolism regulation andantioxidant substance biosynthesis or function as molecular chaperone or protease. Four proteins(a putative ABC transporter ATP-binging protein, NtrX, nesprin-2, Hslu) were new found in highplants, and their functions were estimated from their conserved domain or their homologues inother organism. Our results provided new clue and new insight for us to study thedrought-tolerant mechanism in plants.

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随着全球气候变暖和温室效应加剧,干旱和荒漠化成为威胁人类生存和发展的主要 灾害,许多被子植物对干旱胁迫的生理、生态和生化响应已逐步得以报道,但很少有开 展干旱胁迫对雌雄异株植物的影响方面的研究。由于这类植物在长期进化过程中已经在 生长、性比、生殖格局、空间分布、资源配置和生物量分配等方面形成了明显的性别差 异,因此,干旱胁迫必将对其雌雄植株产生不同的生理生态影响。本研究以青杨为模式 植物,采用植物生态、生理及生物化学等研究方法,系统研究青杨雌雄植株在常温、增 温以及喷施外源脱落酸的条件下对干旱胁迫的响应,揭示其在生长形态、生物量分配、 光合作用、用水效率和生理生化等方面的性别间差异。主要研究结果如下: 1. 青杨雌雄植株对干旱胁迫的综合响应。 与较好水分条件相比,干旱胁迫显著降低了青杨雌雄植株的光合作用和生长发育, 影响了许多生理生化过程,并导致雌雄植株在生长发育、气体交换、用水效率、膜脂抗 氧化和抗氧化系统酶活性方面表现出显著的性别间差异。在较好水分条件下,雌雄植株 之间在株高、基径、生物量、净光合速率、蒸腾速率、用水效率以及丙二醛、脱落酸和 游离脯氨酸等生化物质含量方面均无显著差异。但在干旱胁迫下,雄株在生长发育、气 体交换、水分利用效率、膜脂过氧化保护和抗氧化系统酶活性方面均显著高于雌株,表 现出比雌株更高的株高、基径、叶面积、总叶片数、总生物量、总色素含量、类胡萝卜 素含量、净光合速率、蒸腾速率、羧化效率、光系统II最大光化学效率、内在水分利用 效率、碳同位素组分、过氧化氢酶和过氧化物酶活性等,而在CO2补偿点、比叶面积、 叶绿素a/b、丙二醛、脱落酸和超氧化物歧化酶活性等指标上显著低于雌株。与雌株相比, 雄株表现出更高的干旱胁迫适应能力,而雌株的生长发育和生理生化过程更易遭受干旱 胁迫的影响。 2. 干旱胁迫下的青杨雌雄植株对增温处理的综合响应 与环境温度相比,增温在干旱胁迫前后均显著促进了雌雄植株的生长发育、气体交 换,降低水分利用效率,影响生化物质含量,并促使青杨雌雄植株之间在干旱胁迫下表 现出显著的差异。在较好水分条件下,增温导致雌株的株高、基径、叶面积、总叶片数、 总生物量和超氧化物歧化酶活性显著高于雄株,而用水效率、丙二醛、脱落酸和游离脯 氨酸、抗坏血酸过氧化物酶和过氧化物酶活性低于雄株。在干旱胁迫下,增温将导致雄 株的株高、基径、叶面积、总生物量、净光合速率、蒸腾速率、气孔导度、总色素含量、 相对含水量、过氧化氢酶和抗坏血酸过氧化物酶活性等显著高于雌株,而光系统II 最大 光化学效率、内在水分利用效率、碳同位素组分、丙二醛、脱落酸、游离脯氨酸和超氧 化物歧化酶活性显著低于雌株。与雄株相比,水分较好条件下的增温有利于促进雌株的 生长发育,并在生理生态特征上优于雄株。而干旱胁迫下的增温则加剧了水分胁迫强度, 致使雌株的生长发育遭受比雄株更多的负面影响。 3. 干旱胁迫下的青杨雌雄植株对喷施外源脱落酸处理的综合响应 与对照相比,在干旱胁迫下喷施外源脱落酸可显著增加青杨雌雄植株的生长发育、 气体交换、降低水分利用效率,影响了生化物质含量,并导致青杨雌雄植株之间在干旱 胁迫下表现出显著的生理生态差异。在干旱胁迫下,喷施外源脱落酸致使雌株的株高、 叶面积、叶干重、细根干重、总生物量、净光合速率、蒸腾速率、气孔导度、光系统II 最大光化学效率、非光化学淬灭系数、相对含水量、总光合色素、类胡萝卜素、脱落酸、 超氧化物歧化酶和过氧化物酶活性的增加量显著高于雄株,而根重比、根冠比、细根/ 总根、比叶面积、内在水分利用效率、碳同位素组分、丙二醛、脯氨酸、过氧化氢酶和 抗坏血酸过氧化物酶活性等指标的减少量上显著低于雄株。与对照相比,干旱胁迫下的 喷施外源脱落酸则一定程度能减缓植株遭受胁迫的压力,促进植株生长和气体交换,减 少了植株体内的过剩自由基数量,并促使雌株的生长发育和光合能力显著提高,增强其 抗干旱胁迫能力。 With development of global warming and greenhouse effect, drought and desertification have been became main natural disasteres in resent years. Studies on ecophysiological responses of most angiosperm species to environmental stress have been reported, but little is known about dioecious plant responses to drought stress. Since significant differences on growth, survival, reproductive patterns, spatial distribution, as well as resource allocation between males and females of dioecious plant have been formed during evolutionary process, sexual different ecophysiological responses should be caused by drought stress. In this experiment, Populus cathayana Rehd. was used as model plant to study the sex-related responses to drought by using the ecological, physiological and biochemical methods under normal atmospheric temperature, elevated temperatures and exogenous abscisic acid (ABA) application treatment respectively, and to expose the sexual differences in growth, biomass allocation, photosynthesis, water use efficiency and some biochemical material contents in the males and females of dioecious plant. The results are follows: 1. A large set of parallel responses of males and females of P. cathayana to drought stress Compared with well-watered treatment, drought significantly decreased growth and photosynthesis of P. cathayana individuals, affected some physiological and biochemical processes, and induced males and females to exhibit obvious sexual differences in growth, gas exchange, water use efficiency, lipid peroxidation protection and antioxidant defenses enzyme system. Under well-watered treatment, there were no significant sexual differences in height growth (HG), basal diameter (BD), dry matter accumulation (DMA), net photosynthesis rate (A), transpiration (E), water use efficiency (WUE), and malondialdehyde (MDA), abscisic acid (ABA) and praline (Pro). However, under drought stress, males were found to exhibit higher HG, BD, leaf area (LA), total leaf number (TLA), DMA, total chlorophyll contents (TC), carotenoids content (Caro), A, E, carboxylation efficiency (CE), the maximum efficiency of PSII (Fv/Fm), intrinsic water use efficiency (WUE ), carbon isotope composition (δ13C), catalase (CAT), peroxidase (POD) and lower CO2 compensation point (Γ), specific leaf area (SLA), chlorophyll a/b ratio (Chla/Chlb), MDA, ABA and superoxide dismutase (SOD) than females. The results suggest that males possess greater drought resistance than do females and females suffer more negative effect on growth and development, physiological and biochemical processes than males under drought stress. 2. A large set of parallel responses of drought-stressed males and females of P. cathayana to elevated temperatures Compared with environmental temperature, elevated temperature treatment significant increased growth and gas exchange, decreased water use efficiency, changed some biochemical material contents of P. cathayana individuals, and induced males and females to exhibit obvious differences under drought stress. Under good water condition, elevated temperature treatment caused females to show significant higher HG, BD, LA, TLN, DMA, SOD activity, and great lower WUE, MDA, ABA, Pro, ascorbate peroxidase (APX) and POD than do males. On contrary, under drought condition, elevated temperature treatment induced males to exhibit higher HG, BD, LA, DMA, A, E, stomatal conductance (gs), relative water content (RWC), CAT, APX activity but lower Fv/Fm, WUE, δ13C, MDA, ABA, Pro, SOD activity than do females. The results suggest that females will benefit from elevating temperature under good water condition by possessing better ecophysiological processes than that of males, but will suffer from greater negative effects than do males when grown under drought stress with elevated temperature treatment. 3. A large set of parallel responses of drought-stressed males and females of P. cathayana to exogenous ABA application Compared with controls, exogenous ABA application under drought greatly increased growth and gas exchange, decreased water use efficiency, changed some biochemical material contents in P. cathayana individuals, and induced males and females to exhibit obvious sexual differences under drought. Under drought stress, exogenous ABA application induced females to exhibit more increases in HG, LA, leaf weight (LW), fine root weight (FRW), DMA, A, E, g, Fv/Fm, non-photochemical quenching coefficient (qN), RWC, TC, Caro, ABA, SOD, POD s activity than males, but to show lower decreases in root/weight ratio (RWR), root mass/foliage area ratio (RF), fine root/total root ratio (FT), SLA, WUE, δ13C, MDA, Pro, CAT, APX than males. The results suggest that exogenous ABA application under drought stress will eliminate negative damages caused by drought stress at a certain extent,promote the growth and gas exchange of plant and decrease the number of superfluous 1O2 in plant cells of males and females of P. cathayana. Furthermore, exogenous ABA application promoted more drought resistance in females than in males by increasing more growth and photosynthetic capacity in females under drought stress.

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近年来,随着对作物重茬(连年种植)障碍原因的深入研究,植物的化感作用越来越受到国内外众多学者的重视。而作为重要调料和药用植物的生姜,其连作障碍也备受关注,系统地研究生姜化感作用将有助于理解和最终解决生姜连作障碍问题。本文通过研究生姜不同部位、不同浓度的水浸液对与其间作的两个物种(大豆和四季葱)种子的萌发及幼苗生长的影响,从而证明生姜化感作用的存在;并通过温室盆栽实验研究了生姜的自毒作用(即研究生姜不同部位、不同浓度的水浸液对其幼苗的形态、生理生化、光合作用、土壤酶、土壤微生物多样性及土壤养分的影响),从而揭示生姜退化和衰老的机制,并为生姜筛选出合适的间作物种提供科学依据,对生姜连作障碍提出科学的解决方法。主要研究结果如下: 1. 与对照相比,生姜所有部位(根茎、茎、叶)、所有浓度(10、20、40、 80 g l-1)的水浸液均抑制了大豆种子和葱籽的萌发率、幼苗生长、水分吸收和脂肪酶活性,并且其抑制程度随着水浸液浓度的增加而增强,其生姜各部位水浸液抑制效应的强弱顺序为茎>叶>根茎。这一结果表明生姜根茎、茎、叶含有能够抑制大豆种子和葱籽种子萌发和幼苗生长的水溶性化感物质。根茎是生姜的主要收获部位,而生姜的残株(主要是茎和叶)应该从大田中处理掉以减轻其抑制效应。生姜水浸液中主要化感成分包括:根茎水浸液中主要是丁香酸和伞花内脂;茎水浸液中主要是阿魏酸,且其含量最高为73.4 ug/g;叶水浸液中除了阿魏酸,其他六种物质均检测出来,但含量较高的主要有丁香酸、伞花内脂和香豆酸。 2. 生姜茎和叶不同浓度的水浸液均显著抑制了生姜幼苗的株高、每株叶片数和叶面积,其抑制程度随着水浸液浓度的增加而有所增强,而生姜幼苗每株分枝数差异不显著;同时生姜水浸液也极大程度地影响了生姜幼苗的生物量(包括地下生物量、地上生物量和总生物量,均为鲜重)。在同一浓度下,茎水浸液对生姜幼苗形态指标及生物量指标均显示出最强的抑制作用,叶水浸液次之,根茎水浸液最弱。与对照相比,低浓度的生姜根茎水浸液提高了生姜幼苗叶片内四种抗氧化酶(SOD、POD、CAT、APX)活性,高浓度的根茎水浸液抑制了四种抗氧化酶活性,而茎和叶水浸液均随着浓度的增加而抑制了四种抗氧化酶活性,三种水浸液均随着浓度的增加降低了生姜幼苗叶片内叶绿素的含量,而增加了生姜幼苗叶片的相对电导率和丙二醛含量。同时,三种水浸液均随着浓度的增加降低了生姜幼苗的光合参数(包括胞间CO2浓度、气孔导度、蒸腾速率及净光合速率)。 3. 三种生姜水浸液对所测六种土壤酶活性均产生了不同程度的影响,其中影响最大的是酸性磷酸酶和蔗糖酶,在10 g l-1 时就达到了显著水平,并且所有酶均有随着水浸液浓度增加而增大的趋势;相同部位的水浸液随着浓度的增加,细菌和真菌的数量呈增加趋势,而放线菌的数量呈减少趋势;三种生姜水浸液均随着浓度的增加降低了土壤中有机质的含量,加剧了土壤中硝态氮含量的积累,根茎水浸液对土壤有效磷、速效钾和铵态氮均显示出低浓度提高其含量而高浓度降低其含量的趋势,而茎和叶水浸液则随着浓度的增加均降低了其含量。 4. 与生姜单作相比,所有间作系统均在旺盛生长期和收获期不同程度地提高了土壤酶活性,同时也增加了土壤细菌数量及土壤微生物总数但不显著;所有间作系统在旺盛生长期和收获期均不同程度地影响了土壤真菌及放线菌数量(增加或减少),所有间作系统间的多样性指数差异不显著,除了旺盛生长期四种作物(生姜-大豆-四季葱-大蒜)的间作模式显著降低了多样性指数,其值仅为生姜单作的33.18%;生姜与大豆间作不仅提高了19.6%的生姜产量而且获得了较好的经济效益,并且,所有间作系统均显著抑制了生姜姜瘟病的发生。 5. 不同栽培模式不同程度地影响了收获期生姜的株高、分枝数、根茎产量及内在品质。其中处理2显著地促进了生姜的分枝(10.5%),同时处理2、3和4也促进了生姜的生长(株高分别增加了15.0%、11.4%和14.0%),并且这三个处理提高了生姜的产量;处理2和3能有效提高生姜块茎中维生素C(分别较单作生姜显著提高了3.29%和4.05%)、处理3显著提高了可溶性糖(8.2%)、姜辣素(4.6%)和蛋白质等有益物质的含量,降低硝酸盐有害物质的含量(处理2显著降低了14.0%),改善了姜块的外观和内在品质。并且,生姜与大豆间作具有最高的纯收入和产投比,分别较生姜单作提高了24.80%和8.8%。Recently, allelopathy has been more and more paid attentions by national and foreign scholars with profound research on reasons of crop replanted (continuous planted) obstacle. Ginger rhizome is valuable all over the world either as a spice or herbal medicine and ginger replanted obstacle is also paid attentions. Systematic research on ginger allelopathy will contribute to understanding and ultimate solving problem of ginger replanted obstacle. The effects of ginger aqueous extracts with different parts and concentrations on seed germination and early seedling growth of soybean and chive were studied in this article to testify that ginger existed allelopathy. Furthermore, ginger autotoxicity was also studied by pot experiment in greenhouse (namely research on effects of ginger aqueous extracts with different parts and concentrations on morphological indexes, physiological and biochemical indexes, photosynthesis, soil enzymes, soil microbial diversity and soil nutrients) to reveal mechanism of ginger degeneration and senescence, provide scientific basis for selecting appropriate intercropping species and put forward scientific resolvent for ginger replanted obstacle. The main results were as follows: 1. All aqueous extracts at all concentrations inhibited seed germination, seedling growth, water uptake and lipase activity of soybean and chive compared with the control, and the degree of inhibition increased with the incremental extracts concentration. The degree of toxicity of different ginger plant parts can be classified in order of decreasing inhibition as stem>leaf>rhizome. The results of this study suggested that rhizome, stem and leaf of ginger contained water soluble allelochemicals which could inhibit seed germination and seedling growth of soybean and chive. The rhizome is the main harvested part of ginger. The residue (mainly stems and leaves) of the ginger plant should be removed from the field so as to diminish its inhibitory effect. The main allelopathic components of three kind of aqueous extracts were as follows: Rhizome extract chiefly contained syringic acid and vmbelliferone and stem extract mainly contained frulic acid whose content was the highest (73.4 ug/g). The other six substances were detected except of frulic acid, but only contents of syringic acid, vmbelliferone and p-coumaric acid were higher. 2. Stem and leaf aqueous extracts of ginger with different concentrations significantly inhibited plant height, leaf numbers per plant and leaf area, and the degree of inhibition increased with the incremental extracts concentration. However, tiller number per plant of ginger seedling showed no significant difference. At the same time, ginger aqueous extracts also influenced biomass including under-ground biomass, above-ground biomass and total biomass (fresh weight) to a large extent. Under the same concentration, stem aqueous extract showed the mostly inhibitory effect on morphological indexes and biomass indexes of ginger seedling. Rhizome aqueous extract showed the leastly inhibitory effect and leaf aqueous extract was intervenient. Enhanced concentration of ginger aqueous extracts significantly reduced total chlorophyll content, accompanying with increases in memberane permeability (REL) and lipid peroxidation (MDA). Compared with the control, rhizome ginger aqueous extract of lower concentration (10 g l-1) increased the activities of major antioxidant enzymes (superoxide dismutase, SOD; peroxidase, POD; catalase, CAT; ascorbate peroxidase, APX) of ginger leaf tissue and higher concentration inhibited the activities of four antioxidant enzymes. However, stem and leaf aqueous extract inhibited the activities of four antioxidant enzymes with increase in concentration. Meanwhile, enhanced concentration of ginger aqueous extracts significantly reduced photo-parameters of ginger seedling (including CO2 concentration, stoma conductivity, net photosynthesis rate and transpiration rate). 3. Rhizome, stem and leaf ginger aqueous extract showed different effect on six soil enzyme activities, and acid phosphatase and invertase showed significant effect when aqueous extract concentration got 10 g l-1. Furthermore, six soil enzyme activities increased with increase in aqueous extract concentration. Bcterial and fungi number tended to increase while antinomyces tented to decrease with the increase in aqueous extract concentration of identical part. Ginger aqueous extracts reduced soil organic matter content with increased concentration, accompanying with NO3-—N accumulation in soil. Rhizome aqueous extract showed the same tendency for available P, available K and NH4+—N, namely lower concentration increased their contents in soil and higher concentration reduced their contents. While stem and leaf aqueous extracts reduced their contents with the increamental concentration. 4. All intercropping systems increased soil enzyme activities to different extent both at VGS and at HS compared to solo ginger. All intercropping systems increased the colony numbers of soil bacteria and total of soil microbe but not significantly either at VGS or at HS. All intercropping systems increased the colony numbers of soil fungi and actinomytes to a different extent (increase or decrease) both at VGS and at HS. For DI, difference between all cultivation patterns and S-G was not significant either at VGS or at HS except that G-S-C-G whose value was only 33.18% of S-G at VGS significantly decreased. G-S not only increased ginger yield by 19.6% but also obtained better economic benefit. Furthermore, all intercropping systems significantly inhibited occurrence of bacterial wilt of ginger. 5. Different cultivated pattern influenced plant height, tiller numbers, rhizome yields and intrinsic quality of ginger. Treatment 2 significantly facilitated tiller occurring (10.5%). Treatment 2, 3 and 4 promoted ginger growth (plant height respectively increased 15.0%、11.4% and 14.0%) and enhanced rhizome yields. Treatment 2 and 3 effectively increased vitamin C content (significantly increased 3.29% and 4.05% compared to solo ginger). Treatment 3 significantly increased contents of beneficial substances such as soluble sugar (8.2%), gingerols (4.6%) and protein. Treatment 2 significantly decreased contents of deleterious substance namely nitrate (14.0%) and improved appearance and intrinsic quality of ginger rhizome. Furthermore, treatment 2 (ginger/soybean intercropping) could obtain better economic benefit and showed the highest net income and ratio of benefit and cost whose values respectively increased by 24.80% and 8.8% compared to solo ginger.

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雌雄异株植物对环境的不同响应一直是一个有趣而新颖的研究领域,由于雌雄个体不同的繁殖成本及不同的生存策略,使得雌雄植株在生长、存活、生殖格局、空间分布、资源配置等方面已经表现出明显的不同,在生理和分子水平上也表现出明显的性别间差异。干旱是制约农林业发展的环境因子之一,叶锈病是对杨树危害最严重的病害之一,由于长期进化的结果,不同性别的植物必然对生物和非生物胁迫有着不同的响应。本文以雌雄异株的青杨为模式植物,研究雌雄间在生理、生化、亚细胞结构和蛋白质水平上对生物和非生物胁迫的差异响应。主要研究结果如下: (1) 青杨雌雄植株对锈病胁迫的生理生化差异响应 在正常的对照组中,雄株叶片比雌株叶片有着较高的活性氧自由基产生速率、较高的SOD、POD、PPO 和较低的CAT 活性;在锈病感染的早期阶段, SOD、POD、CAT 活性、活性氧自由基产生速率、H2O2 含量、膜脂过氧化程度和细胞膜的电渗率在雌雄株中都增加,而PPO 仅在雄株中增加明显,APX 仅在雌株中增加明显,并且雌株比雄株有着更严重的锈病感染程度、细胞膜的伤害程度和光合系统II 的破坏程度,雌株有更多的净光合速率、气孔导度和叶绿素a 含量的降低,在同工酶变化上,雌雄间对锈病也显示出不同的表达模式。结果显示,雄株比雌株对锈病有着更好的抗性和更有效的ROS 清除系统。 (2) 青杨雌雄植株对干旱胁迫的生理生化及亚细胞结构的差异响应 与较好水分条件相比,干旱下雄株比雌株有着更高的A-Ci 响应参数,如Rubisco 最大羧化速率、光呼吸速率、暗呼吸速率和最大电子传递速率等。干旱显著地增加了膜脂过氧化程度和游离脯氨酸含量,并且雄株比雌株表现出较低的膜脂过氧化程度,较高的总蛋白和游离脯氨酸含量。无论是中度干旱还是极度干旱,除了CAT 外,雄株比雌株表现为较强的抗氧化酶活性,在同工酶谱带上,雌雄间表现出不同的变化模式,并且有些条带是干旱影响应的,而有些条带是性别特异性的,这些性别特异性条带能够作为鉴定性别快速而准确的标记。干旱显著地影响了线粒体、叶绿体和细胞壁的结构,尤其在中度干旱胁迫下,雄株线粒体和叶绿体比雌株呈现出较好的完整性,并且雄株细胞壁要比雌株更厚。因此, 雄株比雌株表现出更强的干旱忍耐性和更高效的抗氧化酶系统。 (3) 青杨雌雄植株对干旱胁迫的蛋白质组差异响应 用双相电泳检测到雌雄间近1000 个蛋白点,通过对比发现对照组雌雄间有54 个差异蛋白点,干旱下雌雄间有108 个差异点,其中102 个被质谱成功鉴定。对照组雌雄间的差异蛋白主要集中在与光合作用相关蛋白、抗氧化酶、胁迫防御蛋白和一些调节基因表达的蛋白;干旱胁迫下雌雄间差异蛋白明显增多,主要有参与信号转导、调节基因表达、蛋白质加工、转录产物的转录翻译后修饰的调节性蛋白蛋白和参与氧化还原平衡、抗胁迫、细胞壁合成、光合作用、能量代谢、氨基酸代谢和脂肪酸代谢等的功能性蛋白。干旱下这些蛋白的表达量在雌雄中有的表现出相同的表达模式,如干旱下雌雄株中Rubisco 激活酶、小热激蛋白等表达都增加,而有的表现出相反的表达模式,如Rubisco 大亚基的降解片段、羰酸酯酶等在雄株中表达量上调而在雌株中却是下调。因此,雌雄间在蛋白质水平上对干旱胁迫响应的差异是显著的,也是复杂的。 It is an interesting and novel topic that dioecious plants possess different responses to environmental stress. As for the different productive cost and different survive strategy, different sexual plants have shown obviously morphological, physiological and molecular differences. Drought is one of the most worldwidely important environmental stress factors that limit plant growth and ecosystem productivity. Rust disease is one of the economically important diseases in many trees. As a result of the long evolutionary process, male and female plants should show different responses to abiotic and biotic stress. In this paper, using a dioeious tree of Populus cathayana Rehd as a model, we study the sexual differences to drought and rust disease stress in physiological, biochemical, sub-cellular and proteomics levels. The main results are follows: (1) The sexual differences in physiology and biochemistry of poplar to rust disease In controls, males showed higher production of superoxide radicals, higher activities of SOD, POD, PPO and lower CAT activity. Under rust disease, the activities of antioxidant, the content of ROS and the degree of cellular member destroyed were increased in both sexes, except for PPO in diseased males and APX in diseased females. However, females showed more seriously disease severity and cellular member and PS II destroyed degrees. Net photosynthesis rate, transpiration rate and chlorophyll a content were decreased more in diseased females than in males. There were also some different changes inantioxidant isozymes under rust disease. The results suggested that male poplar possessed a more effectively antioxidant system and were more resistant to rut disease than females. (2) The sexual differences in physiology and biochemistry of poplar to drought stress Under drought stress, there were higher rates of RuBP-saturated CO2 assimilation, dark respiration, photorespiratory release of oxygen, the max electron transportrate in CO2-saturated and carboxylation efficiency in males than in females. And males showed lower TBARS and higher proline content. Except for CAT, the activities of other antioxidants were higher in males than in females. Meanwhile, there were obviously differences in isozyme changes between teo sexes. Drought stress obviously destroyed the integralities of chloroplasts and mitochondria and the sexual differences in sub-cellular level were obviously under the moderate water stress. Male cell walls were more sensitive to drought stress than did female. The results suggested males were more resistant to drought stress. (3) The sexual differences in proteomics of poplar to drought stress By 2-D and MS analysis, we identified 102 different protein spots between males and females. Under control conditions, the different proteins were mainly in photosynthesis related proteins, antioxidants, stress response proteins and some gene expression related proteins. Under drought stress, the different proteins were focused on (i) regulated proteins such as signaling conduction, kinase, HSP, gene expressional regulation and protein modification, (ii) functional proteins such as photosynthesis, energy metabolism, antioxidant, redox, stress response, lipid metabolism and amino acid metabolism. Some protein showed the same expressional pattern, while some showed contrary expressional pattern. Thus, the results suggested that sexual differences in proteomics were significant and complex.

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Coral reef organisms are increasingly and simultaneously affected by global and local stressors such as ocean acidification (OA) and reduced light availability. However, knowledge of the interplay between OA and light availability is scarce. We exposed 2 calcifying coral reef species (the scleractinian coral Acropora millepora and the green alga Halimeda opuntia) to combinations of ambient and increased pCO2 (427 and 1073 µatm, respectively), and 2 light intensities (35 and 150 µmol photons/m**2/s) for 16 d. We evaluated the individual and combined effects of these 2 stressors on weight increase, calcification rates, O2 fluxes and chlorophyll a content for the species investigated. Weight increase of A. millepora was significantly reduced by OA (48%) and low light intensity (96%) compared to controls. While OA did not affect coral calcification in the light, it decreased calcification in the dark by 155%, leading to dissolution of the skeleton. H. opuntia weight increase was not affected by OA, but decreased (40%) at low light. OA did not affect algae calcification in the light, but decreased calcification in the dark by 164%, leading to dissolution. Low light significantly reduced gross photosynthesis (56 and 57%), net photosynthesis (62 and 60%) and respiration (43 and 48%) of A. millepora and H. opuntia, respectively. In contrast to A. millepora, H. opuntia significantly increased chlorophyll content by 15% over the course of the experiment. No interactive effects of OA and low light intensity were found on any response variable for either organism. However, A. millepora exhibited additive effects of OA and low light, while H. opuntia was only affected by low light. Thus, this study suggests that negative effects of low light and OA are additive on corals, which may have implications for management of river discharge into coastal coral reefs.

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Ocean acidification affects with special intensity Arctic ecosystems, being marine photosynthetic organisms a primary target, although the consequences of this process in the carbon fluxes of Arctic algae are still unknown. The alteration of the cellular carbon balance due to physiological acclimation to an increased CO2 concentration (1300 ppm) in the common Arctic brown seaweeds Desmarestia aculeata and Alaria esculenta from Kongsfjorden (Svalbard) was analysed. Growth rate of D. aculeata was negatively affected by CO2 enrichment, while A. esculenta was positively affected, as a result of a different reorganization of the cellular carbon budget in both species. Desmarestia aculeata showed increased respiration, enhanced accumulation of storage biomolecules and elevated release of dissolved organic carbon, whereas A. esculenta showed decreased respiration and lower accumulation of storage biomolecules. Gross photosynthesis (measured both as O2 evolution and 14C fixation) was not affected in any of them, suggesting that photosynthesis was already saturated at normal CO2 conditions and did not participate in the acclimation response. However, electron transport rate changed in both species in opposite directions, indicating different energy requirements between treatments and species specificity. High CO2 levels also affected the N-metabolism, and 13C isotopic discrimination values from algal tissue pointed to a deactivation of carbon concentrating mechanisms. Since increased CO2 has the potential to modify physiological mechanisms in different ways in the species studied, it is expected that this may lead to changes in the Arctic seaweed community, which may propagate to the rest of the food web.

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We investigated ecological, physiological, and skeletal characteristics of the calcifying green alga Halimeda grown at CO2 seeps (pHtotal ? 7.8) and compared them to those at control reefs with ambient CO2 conditions (pHtotal ? 8.1). Six species of Halimeda were recorded at both the high CO2 and control sites. For the two most abundant species Halimeda digitata and Halimeda opuntia we determined in situ light and dark oxygen fluxes and calcification rates, carbon contents and stable isotope signatures. In both species, rates of calcification in the light increased at the high CO2 site compared to controls (131% and 41%, respectively). In the dark, calcification was not affected by elevated CO2 in H. digitata, whereas it was reduced by 167% in H. opuntia, suggesting nocturnal decalcification. Calculated net calcification of both species was similar between seep and control sites, i.e., the observed increased calcification in light compensated for reduced dark calcification. However, inorganic carbon content increased (22%) in H. digitata and decreased (-8%) in H. opuntia at the seep site compared to controls. Significantly, lighter carbon isotope signatures of H. digitata and H. opuntia phylloids at high CO2 (1.01 per mil [parts per thousand] and 1.94 per mil, respectively) indicate increased photosynthetic uptake of CO2 over HCO3- potentially reducing dissolved inorganic carbon limitation at the seep site. Moreover, H. digitata and H. opuntia specimens transplanted for 14 d from the control to the seep site exhibited similar delta13C signatures as specimens grown there. These results suggest that the Halimeda spp. investigated can acclimatize and will likely still be capable to grow and calcify in inline image conditions exceeding most pessimistic future CO2 projections.

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There are few in situ studies showing how net community calcification (Gnet) of coral reefs is related to carbonate chemistry, and the studies to date have demonstrated different predicted rates of change. In this study, we measured net community production (Pnet), Gnet, and carbonate chemistry of a reef flat at One Tree Island, Great Barrier Reef. Diurnal pCO2 variability of 289-724 µatm was driven primarily by photosynthesis and respiration. The reef flat was found to be net autotrophic, with daily production of ? 35 mmol C/m**2/d and net calcification of ? 33 mmol C/m**2/d . Gnet was strongly related to Pnet, which drove a hysteresis pattern in the relationship between Gnet and aragonite saturation state (Omega ar). Although Pnet was the main driver of Gnet, Omega ar was still an important factor, where 95% of the variance in Gnet could be described by Pnet and Omega ar. Based on the observed in situ relationship, Gnet would be expected to reach zero when Omega ar is 2.5. It is unknown what proportion of a decline in Gnet would be through reduced calcification and what would occur through increased dissolution, but the results here support predictions that overall calcium carbonate production will decline in coral reefs as a result of ocean acidification.

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Anthropogenic increases in the partial pressure of CO2 (pCO2) cause ocean acidification, declining calcium carbonate saturation states, reduced coral reef calcification and changes in the compositions of marine communities. Most projected community changes due to ocean acidification describe transitions from hard coral to non-calcifying macroalgal communities; other organisms have received less attention, despite the biotic diversity of coral reef communities. We show that the spatial distributions of both hard and soft coral communities in volcanically acidified, semi-enclosed waters off Iwotorishima Island, Japan, are related to pCO2 levels. Hard corals are restricted to non-acidified low- pCO2 (225 µatm) zones, dense populations of the soft coral Sarcophyton elegans dominate medium- pCO2 (831 µatm) zones, and both hard and soft corals are absent from the highest- pCO2 (1,465 µatm) zone. In CO2-enriched culture experiments, high- pCO2 conditions benefited Sarcophyton elegans by enhancing photosynthesis rates and did not affect light calcification, but dark decalcification (negative net calcification) increased with increasing pCO2. These results suggest that reef communities may shift from reef-building hard corals to non-reef-building soft corals under pCO2 levels (550-970 µatm) predicted by the end of this century, and that higher pCO2 levels would challenge the survival of some reef organisms.