西藏齿突蟾蝌蚪冷适应策略研究

本文通过对高海拔两栖类西藏齿突蟾(Scutiger boulengeri)蝌蚪在实验室特定低温条件下的冷适应微空间行为分布的动态变化分析、温度耐受性实验及在不同适应温度的乳酸脱氢酶(LDH)同工酶的酶量与活性比较分析, 探讨了高海拔两栖类蝌蚪的部分冷适应策略。 西藏齿突蟾蝌蚪在不同温度的行为分布是一连续、动态过程，需用多种检验方法综合利用才能进行判断；在15℃, 除低海拔分布的西藏齿突蟾种群外所有实验物种蝌蚪均符合负二项分布、NeymanⅡ型分布；在10℃, 高海拔两栖类蝌蚪均符合负二项分布、NeymanⅡ型分布；在5℃、0℃低温时，高海拔两栖类不同分组的西藏齿突蟾蝌蚪的负二项分布、NeymanⅡ型分布均呈现明显差异, 这可能与高海拔两栖类蝌蚪在低温条件下通过不断地改变其行为分布方式来避免自身被冻伤有关。野外观察表明：高海拔两栖类蝌蚪常选择与流动河水相连的静水水体这种微生境中生存, 蝌蚪应对环境温度极端变化会不断改变其行为分布方式来选择最佳生存温度以避免极端高、低温对自身身体的伤害, 这种对微生境的利用能力对高海拔两栖类蝌蚪耐受极端环境温度的变化极其重要。 两栖类蝌蚪的温度耐受性实验表明不同的驯化温度可以改变西藏齿突蟾蝌蚪、两栖类仙琴水蛙蝌蚪的最适温度、逃避温度，并具有显著影响。 随着驯化温度5℃、10℃逐渐升高, 其最适温度、逃避温度也在一定范围内升高，但驯化温度对低海拔的仙琴水蛙蝌蚪的最适温度、逃避温度的改变效应大于高海拔的西藏齿突蟾蝌蚪的改变效应, 仙琴水蛙蝌蚪对温度的耐受范围、最适温度和逃避温度的ARRS值都大于西藏齿突蟾蝌蚪, 这说明仙琴水蛙蝌蚪对环境温度变化的适应能力大于西藏齿突蟾蝌蚪。 高海拔地区不同分组的两栖类蝌蚪, 在0℃适应温度时, LDH5条带的酶相对含量最高，而在5℃、10℃、15℃适应温度时，LDH5条带的酶相对含量明显都降低, 这表明酵解作用是高海拔两栖类蝌蚪的一些组织在低温﹑缺氧环境中的重要供能方式。高海拔两栖类蝌蚪同一分组的LDH总酶活性总是表现为10℃适应温度的总酶活性最高，而对低海拔的两栖类蝌蚪则是0℃适应温度的总酶活性最高, 这说明高海拔两栖类蝌蚪的LDH同工酶A、B两亚基基因活性在10℃时最高, 而低海拔两栖类蝌蚪的LDH同工酶A、B两亚基基因活性在0℃时最高。同时发现在15℃适应温度组的高海拔两栖类蝌蚪的LDH电泳图谱都有第6条带,有可能由LDH - C亚基组成, 对高海拔两栖类蝌蚪的LDH - C亚基只在15℃适应温度下才表达的机理还有待进一步的研究。 高海拔两栖类西藏齿突蟾蝌蚪通过行为分布方式的改变来选择最佳的生存温度, 这种温度选择过程与野外特定的微生境的存在密切相关, 现在由于人类对河道的不合理利用正在导致高海拔两栖类蝌蚪赖以生存的这种微生境逐渐消失, 这种微生境的消失将加速高海拔的两栖类种群数量衰退的进程。高海拔两栖类物种蝌蚪在低温（0℃）上表现出的同工酶多谱带说明，其A、B两亚基都有所表达，及其参与代谢的方式也是正常的，而低海拔两栖类物种蝌蚪只有A亚基表达的LDH5存在，因此其主要参与酵解过程，这种通过动物自身生理代谢方式的改变来适应极端环境温度条件的变化是高海拔两栖类蝌蚪能适应低温环境的重要策略。但高海拔物种的适应温度变化范围显著小于低海拔物种，对环境温度的变化适应能力有限，特别是对高温区域，因此全球气候变化可能对高海拔物种影响更为显著。 The partly cold-adaptation stratagem of the high altitude amphibian tadpole were researched in the laboratory by analyzing the high altitude amphibian tadpole of Scutiger boulengeri mainly on endpoints related to the dynamic variation of the micro-spatial behavior distribution patterns, the experiment of the temperature tolerance, and the enzyme content and activity of the lactic acid dehydrogenase(LDH) isozyme in special temperature condition. The behavior distribution of the Scutiger boulengeri tadpole is continuous and variable, but it can be figured out by multple testing ways. At 15℃, all of the experiment amphibian tadpoles behavior distribution fit both for the negative binomial distribution and NeymanⅡtype distribution except for the low altitude Scutiger boulengeri tadpoles. At 10℃, all of the high altitude amphibian tadpoles behavior distribution fit both for the negative binomial distribution and NeymanⅡtype distribution. At lower temperature, 5℃ and 0℃, the high altitude amphibian tadpoles of the Scutiger boulengeri at different groups behavior distribution fit for or don’t fit for behavior distribution respectively. It is denoted that the high altitude amphibian tadpoles probably avoid frostbiting by varying the behavior distribution patterns at low temperature condition. The high altitude amphibian tadpoles often actively select the special microhabitat which has the connected still water body and the flowing water body in the wild. It is important that tadpoles can endure the extreme temperature variety in this kind of microhabitat, because tadpoles can be better survival through select temperature condition through migrating in these kinds of microhabitats by varying their own behavior distribution patterns. Different acclimation temperature causes the significant change of preferred temperature(PT)、 avoiding temperature(AT) both in high altitude amphibian Scutiger boulengeri tadpoles and in low altitude amphibian Rana daunchina tadpoles in the temperature endurance experiment. With the acclimation temperature growing from 5℃ to 10℃. the PT and the AT of them would be uprise to some extent, but the effect of acclimation temperature on the PT and the AT of the tadpoles of Rana daunchina is more significant than the ones on the tadpoles of Scutiger boulengeri, at the same, the effects on the temperature endurance range, the ARRs of the tadpoles of Rana daunchina would be stronger than the ones on the tadpoles of Scutiger boulengeri. It is implied that the adaptation ability of tadpoles of Rana daunchina to the surroundings temperature alternation preferred to tadpoles of Scutiger boulengeri. At 0℃ acclimation temperature, the LDH5 enzyme comparative content of the high altitude amphibian tadpoles at different groups was highest, but it becomes lower at 5℃、10℃、15℃ acclimation temperature. It indicated that the alcoholysis role was the important ways of applying energy for special tissue of the high altitude amphibian tadpoles in low-temperature and low-oxygen condition. The total enzyme activity of the LDH of the high altitude amphibian tadpoles in the same group always keeps the highest at 10℃ acclimation temperature, but the low altitude amphibian tadpoles’ was maximum at 0℃. It was denoted that the gene activity of LDH -A and LDH – B submit was highest at 10℃ acclimation temperature for the high altitude amphibian tadpoles, but the low altitude amphibian tadpoles’ was maximum at 0℃. Meanwhile, the LDH electrophoretogram of the high altitude amphibian tadpoles always composed of 6 stripes at 15℃ acclimation temperature，the extra stripe probably was composed by LDH-C submit。It is unknown why LDH-C expresses only under high temperature。. The high altitude amphibian tadpoles can select the most optimal temperature by changing their behavior distribution patterns ceaselessly, but this course of selecting the most suitable temperature correlated with the special microhabitat in the wild closely. Nowadays, this kind of microhabitat which the high altitude amphibian tadpoles rely on are lossing gradually for human being exploit the riverway unreasonably. The disappearing of the microhabitat would accelerate the decline of the high altitude amphibian population. Compare to one band of LDH5, which only composed by the LDH-A submit, presents in the low altitude amphibian at 0℃, the five bands which composed by the LDH-A and LDH-B are checked out, this means the species which occurred in the highland is more adaptable to the low temperature. It is an important stratagem for the high altitude amphibian tadpoles adapt to the limited low temperature depends on the animal energy metabolism change.However, this kind of adaption is restricted, the adaption range to the temperature is much norrow in the high altitude amphibian than in the low one, especially for the high temperature side. The global climate change will be more serious for the high altitude species.

水稻同源四倍体三系法杂种优势利用研究

水稻是重要的粮食作物，其产量的增加和品质的改良都是关系国计民生的大事。就我国现阶段的国情而言，水稻产量在现有水平上稳步提升仍是未来十几年甚至几十年农业生产最重要的目标之一。尽管根据“超级杂交水稻育种”的战略设想和水稻育种实践，通过不断地改进育种技术可望在更高的产量水平上进行水稻杂种优势利用，在稻属植物内还具有很大的产量潜力可以挖掘。然而，仅仅从现有的种质基础出发，要更大幅度提高水稻单产，实现“超级杂交稻”的目标也存在一些困难：现有的推广品种是二倍体，尽管种类众多，但是其基因组的来源相对单一；同时，水稻基因组DNA含量也是作物中最少的，基因组内寻求开发潜力有一定困难；水稻作为C3植物，光合利用效率不高也是制约水稻产量提高的因素之一。因此，寻求常规手段以外的技术突破或者方法创新，是实现“超级杂交稻”的目标的迫切需求。本研究利用秋水仙素能抑制细胞分裂中纺锤丝的收缩、使细胞染色体加倍的作用，对水稻幼穗诱导的愈伤组织细胞进行加倍，并分化出再生植株；创制出水稻同源四倍体新的种质材料，在此基础上选育水稻同源四倍体雄性不育三系材料，并实现水稻同源四倍体的三系配套，开展水稻同源四倍体杂种优势利用和四倍体杂交水稻选育研究，建立水稻同源四倍体杂种优势利用的新技术体系。这不仅有助于倍性水平杂种优势的开拓和利用，同时也将为我国新世纪“超级稻”育种研究开辟一条新的技术途径。 水稻幼穗诱导愈伤组织并分化成苗是一项成熟、简单的组织培养技术。本研究以普通二倍体水稻亲本为材料，用秋水仙素进行水稻的多倍体化诱导，创制同源四倍体水稻三系亲本材料并对其进行鉴定。多倍体化以秋水仙素诱导的愈伤组织培养为基础，研究不同秋水仙素浓度梯度和愈伤组织诱导培养基组合对诱导四倍体植株的影响。结果表明在MS+2,4 D 1.0mg/L+ KT0.2mg/L+ IAA0.2mg/L 和500mg/L的秋水仙素处理下，水稻愈伤组织染色体加倍（有最高的效率）效果较好，平均加倍频率可达25.26%，其中，材料CDR22和IR26诱导较易成功，加倍频率分别达到75%和26.5%；相对材料94109 1.3%加倍频率和冈46B 10.8%加倍频率，诱导率差异极显著。 对水稻四倍体材料进行了形态学鉴定结果表明，与二倍体水稻对照相比其株高、穗长、花粉育性等主要农艺性状，确定四倍体材料在穗长和千粒重两方面极显著提高，种子的长度和宽度也显著增长。对花粉育性鉴定，确认水稻四倍体不育系材料仍为不育，保持系材料自交和杂交可育，恢复系材料自交和杂交可育。对四倍体材料进行细胞形态、染色体数目等方面进行细胞学鉴定，经核型分析表明水稻四倍体材料具有48条染色体，是二倍体水稻的两倍。水稻四倍体材料根尖分生组织细胞与二倍体的根尖分生组织细胞相比，细胞体积、细胞核和核仁显著增大。四倍体三系材料在细胞有丝分裂中期均可规则排列在赤道板，并能均等地移向两极；后期观察中没有发现染色体分离滞后现象，分裂末期细胞能够形成大小相对均一的子细胞。水稻同源四倍体三系材料细胞分裂未见异常，植株生长发育正常。 从1996年至2006年，针对结实率、有效分蘖、着粒数和穗长等主要农艺性状，通过系谱选育的方法，对培育的同源四倍体水稻亲本材料进行了连续选择和改良，取得较好成效。表现为结实率的改良效果极佳，所有改良材料的平均结实率均呈上升趋势，如D237（29.70％→72.70％）、DTB（19.55％→53.21％）等。有效分蘖总体呈现上升趋势，但在不同的年份，如1998和2002存在较大的负向波动。部分材料改良效果明显，如D19B（5.87→13.50）、D什香 (7.00→12.00)等；同时一些材料如DTB和D明恢63虽然总体略有提高，但在不同的年份波动很大，因此存在较大改良阻力，原因还有待进一步研究。着粒数的改良上升趋势比较显著，除保持系的DTB之外，其余材料的平均着粒数有显著提高。穗长的改良阻力较大，虽然不同材料总体上有所提高，但效果并不显著，并且不同年份有较大负向波动（2001）。此外还对株高、剑叶长等性状也进行了选择，但效果不显著，原因有待进一步提高。同源四倍体材料产量相关性状遗传改良幅度不一致，保持系和恢复系间的遗传改良效果也存在差异。这为同源四倍体水稻的进一步利用打下了良好的基础。 籼稻和粳稻亚种间杂交及杂种优势利用的主要障碍就是其低的结实率。而同源四倍体杂交水稻的研究为提高杂交水稻的杂种优势利用创造了新的途径。本研究通过随机区组设计方案，挑选性状优良的二倍体水稻材料，包括雄性不育系，保持系和恢复系进行秋水仙素诱导加倍，从而获得同源四倍体水稻对应的三系材料。利用选育的优良水稻同源四倍体三系材料，配制7个杂交组合，杂交F1代与其恢复系亲本进行比较，用于计算超亲优势（HB）；而杂交F1代与生产上大面积推广的二倍体杂交品种汕优63进行比较，用于计算杂种优势。结果显示，同源四倍体杂交水稻的超亲优势表现为：每株有效穗变化幅度为1.4%至105.9%，总粒数为0.5%至74.3%，每穗实粒数为17.6%至255.7%，结实率为9.6%至130.4%。这些农艺性状的改良使得这7个杂种F1的理论产量的超亲优势高达64.8%至672.7%。小区试验中四倍体杂交水稻组合T461A/T4002和T461A/T4193分别比二倍体对照汕优63提高46.3%和38.3%以上，除一个品种以外所有品种产量均接近或高于汕优63的产量。同源四倍体水稻强大的杂种优势表明，亚种间杂交育性低的问题可通过四倍体化及强化选择来解决。此外，同源四倍体杂交水稻器官的巨大性也是其产量提高的有利因素，水稻同源四倍体三系杂种优势利用研究具有一定的理论价值和商业生产潜力。 Rice is one of the major food crops, the improvement of the production and quality of it is an important thing related to the people's livelihood. On China's current national conditions, steadily increase of the rice yield based on the current level is still one of the most important goals in the next decade or even decades of agricultural production. According to the "super hybrid rice breeding" the strategic and rice breeding practice, improvement of the use of hybrid rice heterosis through continuous improvements in breeding technology is expected to get a higher level of rice yield, there are also a great yield potential can be exploited. However, there are also some difficulties to increase rice yield obviously and implement the goal of "super hybrid rice" based on the existing germplasm: Rice varieties in promotion are diploid, although there are many varieties, but their genome are from a comparatively single source; Meanwhile, the rice genome DNA are the least among the crops, it is difficult to exploit the development potential within the genome; Rice as C3 plants, photosynthetic efficiency is not high, it is one of the factors constraint rice yield. Therefore, seeking technological breakthroughs or innovative methods different from conventional means is the urgent needs to reach the target of "super hybrid rice". Using colchicine inhibit spindle contraction during cell division, double the cell chromosome, we induced callus cells from rice panicle to be doubled, and differentiated regeneration; we created a new autotetraploid rice germplasm material, and on that basis we bred male sterility three line autotetraploid rice materials, and the achieved the three line rice autotetraploid matchmaking, researched in autotetraploid rice heterosis usage and tetraploid hybrid rice breeding, constituted a new technology system of autotetraploid hybrid rice heterosis utilization. This not only helps the tetraploid rice heterosis exploration and use, but also inaugurates a new technical means for China in the new century "super rice" breeding research. We chose ordinary diploid rice as materials, using colchicine to induce the polyploidization, created the autotetraploid rice three-line materials and identified them. The polyploidization was based on the colchicine-induced callus tissue culture, and we experimented different colchicine concentrations and culture mediums to induce tetraploid plants, confirmed that the optimal concentration for inducement was 500 mg/L, the average induce rate was 25.26 %. Among all the materials, CDR22 and IR26 had higher induced rate; in contrary, 94109 and GANG46B had lower induced rate, the difference was significant. Autotetraploid materials was identified of both morphological and cytological, compared plant height, length of pollen sterility, and other major agronomic traits with a diploid rice as the control plant, identified that the autotetraploid materials had very significant advantages in ear length and thousand-grain weight, as well as the size of the seeds. Cytology identification included observation of the cell morphology, the number of chromosomes, and karyotype analysis on the autotetraploid materials confirmed that their chromosome number was 48, twice of the diploid rice. Mitoses in the three lines were common: chromosomes arrayed normally in metaphase and separated balanced into the two poles, chromosome moved without lagging in anaphase and daughter cells normally formed in telophase except one. It has been proved that tetraploid rice has normal meiosis as their diploid relatives, which usually including series of sub-phases as interphase, prophase I (five sub-phases), prophase II, metaphase I, II, anaphase I, II and telophase I, II. However, abnormal phenomena, such as formation of tetravalent, trivalent and univalent, chromosome lagging and so on, which would finally block meiosis. Configurations of chromosome in metaphaseⅠwere versatile in structure and form accept the bivalent. That condition varied in different strain, suggesting more complex paring configurations and more versatile genetic characters in tetraploid rice. All these abnormalities in meiosis contributed to low fertility of gamete and might consequently resulted in low seed setting. Successive selection and improvement on seed set, productive tiller per plant, total grains per panicle, panicle length and so on had been carried out from 1996 to 2006. The raise of seed sets was significant in both restorers and maintainers. Seed sets of some strains were improved more significantly than others, for example D237（29.70％→72.70％）、DTB（19.55％→53.21％）and et al.. Productive tiller per plant was improved to some extant. The tendency of improvement was rising on the whole but changed in some years such as 1998 and 2002. Part of the stains increased greatly, such as D19B（5.87→13.50）、Dshixiang (7.00→12.00) and so on, but some strains including DTB and Dminghui63 only increased little and decreased in some years by unknown reason. Total grains per panicle increased significantly and all strains except DTB increased. Improvement of panicle length termed to be hard. Different strains showed different capacities for improvement and floating existed in different years for example 2001. It has been proved that other agronomical traits including plant length, flag leaf length and so on could be improved but not significantly by selection also. In a word, agronomical traits could be raised by successive selection that is prerequisite for further utility of autotetraploid rice. Poor fertility is the main barrier for utilizing heterosis between the two rice (Oryza stiva L.) sub-species, indica and japonica. Recently, the development of autotetraploid hybrids (2n=4x=48) has been suggested as a new method for increasing heterosis in hybrid rice. Using standard experimental protocols, the elite diploid rice male sterile, maintainer, and restorer lines were colchine-doubled and autotetraploid counterparts were obtained. Seven resulting hybrids were analyzed for heterobeltiosis (HB), where the F1 was compared to the male parent, and the degree of heterosis, where the F1 was compared to the diploid commercial hybrid, Shanyou 63. The HB among the autotetraploid hybrids ranged from 1.4 to 105.9% for the productive panicles per plant, 0.5 to 74.3% for total kernels per panicle, 17.6 to 255.7% for filled kernels per panicle, and 9.6 to 130.4% for seed set. Improvements in these yield components resulted in the HB for kernel yield ranging from 64.8 to 672.7% among the seven hybrids. Hybrids T461A/T4002 and T461A/T4193 yielded 46.3 and 38.3% more, respectively than Shanyou 63, and all other hybrids but one yielded the same or more than Shanyou 63. The high heterosis for yield suggests that hybrid sterility between two rice sub-species may be overcome by using tetraploid lines followed by intensive selection. Also, the gigantic features of the autotetraploid hybrids may establish a plant structure able to support the higher yield.

泥生绿菌的分离鉴定及其在净化废水中作用的初步探讨

本文介绍了从厌氧间歇膨胀光合反应器内的活性污泥中分离并鉴定的泥生绿菌(Chlorobium limicola Nadson)S1,它属严格厌氧光能自养型细菌，在有硫化物和少量碳酸氢盐存在下，有广泛利用有机物的能力，它的最适生长温度为28-30℃,最适生长PH为6.5-7.0，且含有氢化酶。因此，它能与甲烷发酵菌共存而共同作用，达到废水净化之目的。通过光照(2#反应器)和黑暗(1#反应器)对比实验，表明了在光照条件下即有泥生绿菌S1存在下，反应系统能更好地降低CODcr、BOD5 和提高CH4 含量，在四个负荷段的运行中，2#反应器在后三个负荷段的甲烷含量能稳定在91.6%而1#反应器为87%，2#反应器的二氧化碳含量为4.5%而1#反应器为8.8%，于28.35g/l.d的负荷下，2#反应器CODcr去除率达83.4%，BOD去除率达74.53%，分别较1#反应器高10.8%,6.4%。COD去除率提高了14%，BOD去除率提高了9.3%。本试验的试验条件为：白天自然光照，晚上电源光照，光照强度为1000-2500lux，通过连续动态运转，并以恒定的流速将废液注入反应器中，进水PH控制在6.5-7.2，反应器厌氧，恒温室温度控制在30±1℃。为使整个试验中同一水质条件下进行，进水采用化学合成培养基。This paper reports a Chlorobium Liwicola S1's isolation and identification. It is a strictly anaerobic and photosynthetic autotrophic bacterium. Along with sulfidedepondent CO2 assiwilaton,a few simple organic compounds can be photoassimilated. Acetate is most effectively used. Its best conditons of growth are 28-30℃,PH 6.5-7.0, and it contains hydrogenase. So it can live with methanefermentative bacteria in order to treat wastewater. At the same time, the treatment of wastwater using Chlorobium Limicola S1 with methane-fermontative bacteria under dark anaerobic and light anaerobic conditions is studied. In contrast with 1# reactor-darken, 2# reactor-illuminated can lossen wastewater's CODcr, BOD5 and on hance CH4 content better. In the test, 2# reactor's CH4 content is stable at 91.6%, but 1# reactor's is 87%. The CO2 content of 2# reactor is 4.5%, but 1# reactor's is 8.8%. When the load of teatment is 28.35g/l.d, the COD removal effficiency is 83.4% and the BOD removal efficiency is 74.53% in 2# reactor. They are separately 10.8%, 6.4% higher than 1# reactor's.

Natural 13C abundance as a tracer for studies of soil organic matter dynamics

A method for measuring the long- and medium-term turnover of soil organic matter is described. Its principle is based on the variations of 13C natural isotope abundance induced by the repeated cultivations of a plant with a high 13C/12C ratio (C4 photosynthetic pathway) on a soil which has never carried any such plant. The 13C/12C ratio in soil organic matter being about equal to the 13C/12C ratio of plant materials from which it is derived, changing the 13C content of the organic inputs to the soil (by altering vegetation from C3 type into C4 type) is equivalent to a true labelling in situ of the organic matter. Two cases of continuous corn cultivation (Zea mays: δ13C = −12%.) on soils whose initial organic matter average δ13C is −26%. were studied. The quantity of organic carbon originating from corn (that is the quantity which had turned-over since the beginning of continuous cultivation) was estimated using the 13C natural abundance data. After 13 yr, 22% of total organic carbon had turned-over, in the system studied. Particle size fractions coarser than 50μm on the one hand, and finer than 2μm on the other. contained the youngest organic matters. The turnover rate of silt-sized fractions was slower

黄土丘陵区翻白草光合特性的研究

对典型草原云雾山保护区退耕6 a,11 a(放牧8 a)和16 a的3个退耕地和4个封育草地(百里香群落、铁杆蒿群落、大针茅群落和长芒草群落)对照坡耕地表层土壤的水分特征曲线数学模型、持水参数和比水容量进行了测定。结果表明,封育草地的持水和供水性能要大于退耕地和坡耕地,放牧对退耕11 a的持水和供水性能有较大影响。云雾山自然保护区坡地退耕和草地封育后,样地土壤的持水能力大小顺序为封育长芒草群落>大针茅群落>百里香群落>铁杆蒿群落>退耕16 a>退耕6 a>坡耕地>退耕11 a(放牧8 a)。供水能力大小顺序为封育长芒草群落>百里香群落>铁杆蒿群落>大针茅群落>退耕16 a>退耕6 a>退耕11 a(放牧8 a)>坡耕地。这说明土壤持水和供水性能随着退耕年限的增加和封育草地的正向植被演替均逐渐增强的趋势。坡地退耕和草地封育能够通过改善土壤的水分物理性质提高土壤的蓄水持水性能和抗侵蚀能力。

黄土塬区氮磷配施对冬小麦光合作用、产量形成及水分利用的影响

在黄土高塬沟壑区,研究了不同施肥条件对冬小麦各个生育期的叶面积指数、光合作用、干物质积累、产量形成以及水分利用的影响,结果表明:与对照相比,施肥后小麦叶面积指数和光合速率都显著提高,同化作用增强,平均产量提高了47.6%,水分利用效率提高了24.6%。不同的肥料配施对冬小麦的干物质积累、产量以及水分利用效率的影响顺序基本一致,即高氮高磷>高氮低磷>低氮低磷>低氮高磷,但方差分析表明,在这种氮磷配施方案中起作用的主要是氮肥,磷肥的贡献不大,且二者并没有产生明显的交互作用。

变水处理与短期遮荫对作物水分利用效率的影响

变水处理与短期遮荫对棉花水分利用效率的影响研究表明 ,在充分供水 -水分胁迫 -复水的变水处理过程中 ,短期遮荫使净光合速率、蒸腾速率、水分利用效率降低 ;光照 -遮荫 -光照期间 ,总的水分利用效率以水分胁迫的最高 ,充分供水的次之 ,复水处理最低 ,其中遮荫 40 %的水分利用效率高于遮荫 75%的处理 .回归分析表明 ,水分利用效率与光合速率表现出极显著正相关 ,两者回归直线的斜率随水分胁迫而增大 ,而水分利用效率与蒸腾速率的关系较弱 ,多数处理两者相关达不到显著水平

水肥空间组合对冬小麦光合特性及产量的影响

以肥熟土垫旱耕人为土为供试土壤,用分层土柱试验法研究了不同土层水分、氮、磷空间组合对冬小麦不同生育时期光合特性及籽粒产量的影响.结果表明:与0～90cm土层整体湿润相比,上干下湿(0～30cm土层干旱胁迫,30～90cm土层湿润)水分处理显著降低了小麦叶片叶绿素相对含量(SPAD)、净光合速率(Pn)和籽粒产量.2种水分条件下,氮磷配施处理对叶片SPAD、Pn和小麦籽粒产量的影响最为显著,其次是施磷处理,而施氮处理影响不显著.不同土层施氮在2种水分条件下各指标的变化趋势相同,均表现为0～90cm土层施氮小麦叶片SPAD、Pn及籽粒产量显著高于0～30、30～60和60～90cm土层施氮.不同土层施磷在2种水分条件下各指标的变化趋势也相同,表现为0～90cm土层施磷小麦叶片SPAD、Pn和籽粒产量与0～30cm土层施磷间差异不显著.不同土层氮磷配施在2种水分处理下表现不同:整体湿润条件下0～90cm土层施肥处理的小麦叶片SPAD、Pn及籽粒产量最高,与0～30cm土层差异不显著,但二者均显著高于30～60和60～90cm土层处理;上干下湿条件下各土层施肥处理间小麦叶片SPAD差异不显著,0～90cm土层施肥处理...

氮素形态和铁营养对玉米苗期生长及体内铁分布的影响

以玉米(Zea mays)品种‘豫玉-22’为材料,采用营养液培养方法,研究了低铁和正常供铁条件下供应不同形态氮素对玉米苗期生长及体内铁分布的影响。结果表明:(1)与低铁介质相比,常铁介质增加了各氮素处理玉米幼苗的株高、地上部干重、全株干重,降低了根冠比,其中硝态氮处理表现得尤其突出;与供应硝态氮(NO3--N)相比,增施铵态氮(1/2 NO3--N+1/2 NH4+-N,NH4+-N)能明显促进低铁介质中玉米生长,但在常铁介质下作用不明显。(2)相比于低铁介质,正常供铁显著提高了相应处理玉米新叶叶绿素含量及净光合速率;2种供铁介质中,NH4+-N处理的新叶叶绿素含量以及净光合速率均高于其它氮素处理。(3)相比于低铁介质,正常供铁处理总体上增加了玉米各部分活性铁含量和全铁含量,对NO3--N处理的新叶活性铁含量增加尤其明显;2种供铁介质中,NH4+-N均有利于提高新叶活性铁含量和植株地上部全铁含量。(4)玉米新叶活性铁含量不仅与其叶绿素含量显著正相关(r=0.979**),也与叶片净光合速率显著正相关(r=0.950**)。研究发现,供铁状况显著影响玉米新叶的叶绿素含量及其净光合速率且与供氮形态存在互作;供应...

水肥交互作用对黄土高原南瓜光合特性及其产量的影响

通过不同的灌水和施肥处理,研究水肥交互作用对南瓜光合特性日变化及产量的影响,结果表明:水分与施肥因子对南瓜叶片的光合特性和产量有重要影响,在水分胁迫的情况下,肥水交互作用不显著,在水分较低的情况下,二者表现互为限制条件的协同作用;在水分较高的情况下,肥水交互作用转变成顺序加和作用。其中单因素效应大小表现为:氮>水>磷,耦合效应大小表现为:氮与水耦合>氮与磷耦合>磷与水耦合。在水分适宜时,适宜的施肥量(施氮量50kg/hm2、施磷量35 kg/hm2)可以提高南瓜光合速率和产量,不施肥或施肥量过高都会影响南瓜光合速率和产量。

干旱和复水条件下转基因甘薯的光合特性

以转铜锌超氧化物歧化酶(Cu/Zn SOD)和抗坏血酸过氧化物酶(APX)基因甘薯(TS)及未转基因甘薯(NT)为实验材料,研究在旱后复水条件下转基因甘薯及未转基因甘薯抗氧化酶活性和光合特性变化。结果显示,连续36 h胁迫条件下,TS和NT的SOD活性都先降低后升高,但TS的SOD活性始终高于NT。胁迫至24 h时,TS的SOD活性约为NT的1.2倍,复水后二者SOD活性都下降。持续胁迫,TS的APX活性先升高后降低,NT与之相反,复水后TS和NT的APX活性都是先升高后降低,复水12 h,TS的APX活性是NT的1.5倍。水分胁迫条件下TS的膜质受伤害程度要轻于NT,胁迫24 h,复水12 h,NT的MDA含量均约为TS的1.2倍。胁迫12 h,TS和NT净光合速率都下降,继续胁迫,TS净光合速率开始上升,NT几乎保持不变,胁迫36 h,TS的净光合速率约为NT的1.5倍。复水后二者净光合速率都开始上升,复水12 h,TS净光合速率约为NT的3倍。胁迫时TS、NT胞间CO2浓度(Ci)都逐渐增大,胁迫36 h时NT胞间CO2浓度显著高于TS,是其1.4倍。实验结果表明,同时转入SOD、APX抗氧化基因后,在...

土壤水分与短期遮光对棉花光合及其气孔响应的影响

以陆地棉 (Gossypium hirsutum L.Zhongmain No.2 3)为供试材料 ,探讨了在充分供水-水分胁迫 -复水的处理过程中 ,短期不同遮光水平对棉花光合特性及其气孔响应的影响。结果表明 ,在水分处理过程中 ,所有不同遮光水平的棉花叶片对短期遮光具有相似的基本响应规律 :短期遮光使净光合速率迅速降低 ,气孔导度减少 ,但减少速率缓慢 ;遮阳网去掉后 ,叶片气孔重新开放速率和光合恢复被延迟。水分胁迫期间 ,所有遮光处理的水分利用效率均最高 ,但净光合速率均较低 ,光合及其气孔响应受到严重限制 ,遮光 75%受到的影响大于遮光 40 %的处理。复水后水分胁迫带来的残留影响仍然存在 ,结果使水分利用效率在整个水分处理过程中最低 ,遮光 75%的处理尤为明显。上述表明 ,土壤水分与短期遮光对棉花光合及其气孔响应的影响十分显著

水分处理对油菜叶位光合速率、蒸腾速率及水分利用效率的影响

通过对不同水分处理下油菜不同叶位叶片光合速率(Pn)、蒸腾速率(E)和水分利用效率(WUE)的测定表明,油菜主茎叶片的光合速率、蒸腾速率和水分利用效率随叶位的降低而降低;干旱胁迫下油菜水分利用效率显著提高,光合速率变化不明显,但上部、下部叶间光合速率差异大。充分供水时叶片的蒸腾速率提高,水分利用效率则降低,从上到下叶片水分利用效率、光合速率降低不剧烈,而蒸腾速率表现为上部和下部叶高,而中部叶低。据测定,干旱处理下油菜单株生物量为37.45g,充分供水时为38.76g,干旱导致油菜生物量降低;水分胁迫能提高作物水分利用效率;在充分供水条件下叶片蒸腾速率较高,这可能是气孔行为的结果。

黄土丘陵区铁杆蒿光合特性

铁杆蒿(Artemisia sacrorum)是菊科(Compositae)蒿属(Artemisia)半灌木状草本,主根木质,生长于我国西北部陕西、甘肃、宁夏、青海、新疆和西南部的西藏等省区海拔1500～4900m的山坡、半荒漠草原、滩地,而且在局部地区为植物群落优势种的主要伴生种(林有润,1991)。铁杆蒿群落是半干旱黄土丘陵沟壑区一种较稳定的地带性植被,也是黄土高原生态脆弱带植被恢复中需要重点研究的天然植物群落之一(王国梁等,2002)。至今对铁杆蒿的研究还不多,主要集中于精油的化学成分(顾静文等,1999)、群落种间联结性(王国梁等,2002)、群落生物量及地上部数量特征(张娜等,1999a;1999b)上,而对铁杆蒿的光合蒸腾特性研究尚未见报道。本文利用Li-6400便携式光合测定系统在野外测定了自然条件下铁杆蒿的光合作用及其对光的响应曲线,旨在了解铁杆蒿的光合与蒸腾特性,为黄土高原植被建设提供理论依据。1试验区自然概况试验地设于陕西延安燕沟流域的康家屹崂沟小流域内。位于109°16′10″E,36°26′36″N,海拔1000～1200m,属暖温带半湿润偏干旱季风气候区,位于黄土丘陵区森林草原地带,...

土壤养分对小偃22叶片光合特性影响的初步研究

在大田不同供肥条件下 ,于小麦灌浆后期对小麦旗叶光合特性参数进行了连续测定。结果表明 ,小麦叶片气体交换参数均有明显的日变化趋势 ,肥力条件对其日变化进程具有明显的调控作用。不施肥处理小麦叶片 Pn有明显午休现象 ,而低肥处理第一高峰不明显 ,没有明显午休现象 ;高肥处理的 Pn呈单峰曲线 ,峰值来得也较晚。养分条件可改善小麦叶片水分利用效率