岷江干旱河谷三种蔷薇植物繁殖更新研究

繁殖更新是植物生活史的重要阶段，在退化生态系统中，植物繁殖更新能力往往较差，是植被恢复的限制环节，因而也成为恢复研究重点和核心。本研究选择岷江干旱河谷广泛分布的三种蔷薇：多苞蔷薇（R. multibracteata）、黄蔷薇（R. hugonis）和川滇蔷薇（R. soulieana）为研究对象，通过野外调查，在查明其生长、繁殖更新状况的基础上，采用控制和模拟实验，对种子和幼苗阶段进行了深入研究，综合分析更新潜力，并提出相对应的促进更新和植被恢复措施。主要结论如下： 1）三种蔷薇在岷江干旱河谷广泛分布，生长和繁殖状况良好，结实量大。各生长指标：株高、基径和冠幅，繁殖指标：结实数量、重量和单果重量都具有显著的空间差异性。基径对多苞蔷薇结实量影响最大；而冠幅对黄蔷薇结实量影响最大。海拔和纬度是对蔷薇生长和繁殖影响最大的环境因素，随着海拔和纬度的升高，植株生长更高大，结实量增加；坡度和坡向对其生长和繁殖也有一定影响，随着坡度 和坡向增加，蔷薇生长和结实受到抑制。 2）三种蔷薇在岷江干旱河谷更新现状不佳, 但更新潜力大。活力种子比率低，动物取食以及两年生幼苗的大量死亡是蔷薇更新的主要限制因素。多苞蔷薇和黄蔷薇的结实率低，川滇蔷薇较高。三种蔷薇种子产量大，但种子质量较差，更新具有充足的种源。三种蔷薇都能形成持久种子库，种子库中种子总量大，但有效种子少，黄蔷薇被动物啃食的比例很高，多苞蔷薇和川滇蔷薇也有一部分种子受到动物破坏。三种蔷薇幼苗库组成特征表现为，当年生幼苗所占比例很高，年龄较大幼苗所占比例小。 3）三种蔷薇都具有不同程度休眠，未经处理种子的发芽率极低。黄蔷薇休眠程度最深，为深度生理休眠；多苞蔷薇为中度生理休眠；川滇蔷薇为非深度生理休眠。三种蔷薇种子在形态上发育成熟，种皮具有透水性。蔷薇果果肉和瘦果中含有抑制物质，其浸泡液抑制了油菜种子萌发，果肉抑制作用更强，果肉和瘦果浸泡液的抑制程度分别为：川滇蔷薇>黄蔷薇>多苞蔷薇。切割和硫酸腐蚀提高了川滇蔷薇种子的发芽能力，而对多苞蔷薇和黄蔷薇没有影响。完全去除瘦果果皮和种皮提高了多苞蔷薇种子发芽率，但对黄蔷薇没有影响。赤霉素和烟水对蔷薇种子萌发没有促进作用。三种蔷薇打破休眠所需低温层积时间分别为：黄蔷薇>多苞蔷薇>川滇蔷薇。对于多苞蔷薇和川滇蔷薇，层积前对种子进行硫酸腐蚀或暖温层积能缩短低温层积时间，提高发芽率。对于多苞蔷薇，变温层积中暖温层积和低温层积具有一定的负补性，即延长暖温层积可以缩短种子萌发对低温层积的需要。 4）多苞蔷薇种子形态特征和种子休眠与萌发在不同海拔梯度间存在较大差异。种子采集时间、采集季节和干藏影响多苞蔷薇和川滇蔷薇的种子休眠。多苞蔷薇果实大小、种子大小和千粒重、种皮厚度随海拔升高而增加，而种子饱满率和活力随海拔升高而降低，种子休眠程度也随海拔升高而增加。种皮厚度与种子大小、千粒重成正相关关系，硫酸腐蚀后的种子经过不同时间的低温层积后，种子发芽率与种皮厚度、种子大小、千粒重、海拔成正相关关系。2006 年采集川滇蔷薇和多苞蔷薇种子休眠程度较2005 年低。种子休眠随种子年龄增加而减弱。高温和干旱能减轻多苞蔷薇和川滇蔷薇种子休眠。 5）三种蔷薇的生长和生物量积累在干旱胁迫条件下受到抑制，而生物量分配、叶片形态特征和水分利用特征等都发生了变化。三种蔷薇的根、茎、叶各器官生物量以及总生物量等在干旱胁迫下明显减小，叶片脱落数量增加。在干旱胁迫条件下，较多的生物量分配到地下部分，从而这使R/S 明显增加。比叶面积（SLA）和冠层面积比（LAR）对干旱胁迫的反应不敏感，仅有部分物种在干旱胁迫条件下发生了变化，并且其变化特点在不同年龄幼苗之间有一定差异。干旱胁迫对WUE 的影响在不同物种间存在差异。多苞蔷薇和黄蔷薇的WUE 随着干旱胁迫的增加而增大， 而川滇蔷薇的WUE 则随干旱胁迫增加而减小。在干旱胁迫条件下，多苞蔷薇和黄蔷薇叶片脱落量和生物量减小幅度较川滇蔷薇大，表明其抗旱能力较强。在干旱胁迫条件，三种蔷薇两年生幼苗的生物量减小幅度较当年生幼苗小，表明两年生幼苗的抗旱能力更强。 6）两种植被恢复措施中，幼苗移栽比播种具有更好的植被恢复效果。播种后，蔷薇种子的发芽率较高，但出苗率都很低，即使出苗，幼苗也几乎在一月内全部死亡。 三种微生境条件下（灌木、半灌木和裸地），种子出苗和幼苗成活没有差异。移栽幼苗总体死亡率都比较低，小于20％。特别是两年生幼苗死亡率更低，小于2％。移栽后的幼苗生长状况良好，在整个生长季中，各生长指标不断增加。生境对幼苗的存活率没有显著影响，但对于幼苗的生长和生物量积累有一定影响，裸地更有利于幼苗生长和生物量积累。与当年生幼苗相比，两年生幼苗具有更高的成活率。总之，三种蔷薇在干旱河谷分布广泛、生长繁殖状况良好，结实量大，具有丰富种源，繁殖更新潜力大，但繁殖更新状况不佳；种子散布后动物对种子的取食、种子的深度休眠过程、种子出苗以及当年生幼苗的存活和定居是更新的主要限制环节。水分是影响结实、种子休眠解除和萌发，幼苗存活和定居的最主要的限制因素。在植被恢复中，应在种子成熟季节大量采集种子，在室内打破休眠后进行人工播种，培育两年生幼苗，通过幼苗移栽方式进行植被恢复。川滇蔷薇应栽种在相对湿润的过渡区，而多苞蔷薇和黄蔷薇可以应用于核心区植被恢复。 Regeneration is an important phase in plant life cycle. It has been a key component of ecological restoration in degradation ecosystem in which plants commonly has poor regeneration. In this paper, we investigated the natural growth, propagation and regeneration status of native three rose species, Rosa multibracteata, R. hugonis and R. soulieana, and analysis the limitation in seed germination and seedling establishment stages. Advice on facilitating the use of these plants in restoration based on the results has been proposed. The results were as follows: 1) Three rose plants widely distributed in the dry valley of the Minjiang River, and made a good performance in growth and propagation. There were significant spatial differences in each growth parameter, such as ramet height, basal diameter, crown diameter and propagation parameters including hip number of a clump, hip mass of a clump and a hip mass. Basa diameter was the most important growth parameter influencing fruit number for R. multibracteata and crown diameter was for R. hugoni. Altitude and latitude had the greatest effect on the growth and propagation of rose plants among environmental conditions. Each parameter of growth and propagation increased with the increase of altitude and latitude. In addition, the increase of slope and aspect limited the growth and propagation. 2) Three rose plants had poor natural regeneration, but great regeneration potential. Low seed viability, predation and higher mortality of current year old seedlings were the limitation in regeneration. R. multibracteata and R. hugonis had higher fruiting rates than R. souliean. All three plants produced a great number of seeds, while their viability was poor. Three rose plants had persistent seed banks, with high total seed number but very low viable seed density. Predation was most severe in R. hugonis, and it also existed to some degree in R. multibracteata and R. soulieana. The seedling age-structure was characteristic of current-year seedlings predominating and few older seedlings were observed. 3) Three rose seeds were dormant and untreated seeds germinated with very low germination percentages. The rose seeds had morphological mature embryos, and achenes were permeable. Some inhabit substances existed in hips and achenes for the extracts of hips and achenes inhibited germination of Brassica campestris. The inhibition effect of the extracts of three rose hip and achenes was R. soulieana>R. hugonis>R. multibracteata. Mechanical and H2SO4 scarification increased R. soulieana germination but had no effect on germination of R. hugonis and R. multibracteata seeds. Full removal of pericarp and testa improved the germination of R. multibracteata but did not affect R. hugonis germination. GA3 and smoke water had no positive effect on rose seed germination. The periods of cold stratification required to released seed dormancy was R. hugonis > R. soulieana >R. multibracteata. H2SO4 scarification and warm stratification shortened cold stratification to release dormancy for R. soulieana and R. multibracteata. Warm stratification had complementary effect for cold stratification, i.e. the longer warm stratification seeds received, the shorter cold stratification were required to obtain the same germination percentage. Three rose seeds had different kinds of dormancy; R. hugonis has deep physiological dormancy, R. multibracteata with intermediate physiological dormancy and R. souliean non-deep physiological dormancy. 4）The seeds traits and dormancy of R. multibracteata showed significant difference across altitudes. Year and season of seed collection had significant effect on seed dormancy for both R. souliean and R. multibracteata. Hip size, seed size, seed weight, seed coat thickness and seed dormancy level increased with the increase of the altitude. There were positive relations between seed coat thickness with seed size and seed weight. Germination percentage of seeds treated with H2SO4 scarification following different periods of cold stratification showed positive relation with seed coat thickness, seed size, seed weight and altitude. Seeds of R. souliean and R. multibracteata collected in 2006 had low dormancy level than those collected in 2005. Seed dormancy decreased with increasing seeds age. High temperature and drought were associated with low dormancy level. 5) Seedling growth, the total dry mass and their components of seedlings were reduced, while leaf senescence accelerated under drought stress. More biomass allocation to root system resulted in higher R/S ratio under drought. Water-use efficiency (WUE) of R. multibracteata and R. hugonis increased, while it declined for R. soulieana under drought stress. R. soulieana seedlings had poor drought-resistance capacity it had more senescent leaves, and its reduction of biomass was stronger than two other rose plants under drought. The reduction degree of one year old seedlings under drought stress was slighter than that of current year seedlings. Therefore, one year old seedling was more drought-resistent compared to current year seedlings. 6）Planting seedlings may have better effect in comparison with direct seeding. Most seeds germinated after seeding, but seedling emergence was very low. More than 80 % seedlings from direct seeding died within a months after emergence. Seedling emergence and survival rate did not show difference among microhabitats. Mortality rates of seedlings artificially planted in microhabitats were general lower than 20 %, and the mortality rate of one year old seedlings was lower than 2 %. Each grow parameter including plant height, leaf number and branch number continually increased after planting. Microhabitat type had effect on the growth parameter and biomass production, but it did not influence the seedling survival. Bare land tended to facilitate seedling growth. One year old seedlings had higher survival rate than current year seedlings. In conculsion, the three rose had wide distribution in the dry valley of the Minjiang River. They produced many seeds and had tolerance to drought stress to some degree. But they had poor regeneration in habitats may be caused by predation, seed dormancy，and high mortality in current year seedlings. We recommend that rose plants should be utilized in restoration by planting two-year old seedlings in spring. A large quantity of seeds should be collected artificially in autumn, release seed dormancy in room, and then cultivate two-year old seedlings by seeding in particular container. R. soulieana seedling probably be planted in transition area, and R. multibracteata and R. hugonis can be used in core area of the dry valley of the Minjiang River.

增强UV-B辐射对粗枝云杉(Picea asperata Mast.)和青杨(Populus cathayana Rehd.)的影响

光是植物赖以生存的重要环境因子，但是植物在获得光的同时不可避免的会受到紫外辐射的伤害。尤其是近年来，人类向大气中排放的大量氮氧化合物和氟氯烃类化合物(CFC’s)引起臭氧分子的分解，导致到达地球表面的紫外辐射增加，特别是UV-B辐射增强。而另一方面，植物对UV-B辐射反应的敏感性在种间和品种间存在差异，主要受植物基因型，生态型和生活型的控制。本项目分别以粗枝云杉和青杨组杨树为模式植物，从形态和生理生化方面分别研究了来自不同水分背景下的粗枝云杉种群和来自不同UV-B背景下的青杨种群在增强UV-B下的反应及其反应差异,并探讨了干旱、喷施外源脱落酸(ABA)对它们抗UV-B能力的影响。研究成果可为生态系统的恢复与重建提供理论依据和科学指导。主要研究结果如下： 1. 粗枝云杉的两个种群，湿润种群(来自四川黑水)和干旱种群(来自甘肃迭部)在水分良好和干旱状况下表现出对增强UV-B的不同响应。同时，干旱对粗枝云杉抗UV-B能力的影响也得到研究：两种胁迫共同作用时，干旱表现出在一定程度上减弱了增强UV-B对粗枝云杉的生理特性的影响。 干旱胁迫显著降低了两个粗枝云杉种群的光合同化速率(A), 气孔导度(gs)和PSII的有效光量子产量(Y), 同时，提高了非光化学猝灭效率(qN)和超氧化物歧化酶(SOD)的活性。与湿润种群相比，干旱种群抗旱性更强，表现为干旱种群拥有更高的SOD和干旱进一步加剧了UV-B的胁迫效应。 本研究中，干旱胁迫单独作用时，显著降低了青杨两个种群的生物量积累和气体交换，具体包括A、gs、蒸腾速率(E)和光合氮利用效率(PNUE)，提高了两个种群的瞬时水分利用效率(WUEi)、长期水分利用效率(WUET)、碳同位素组分(δ13C)和氮含量(N)。同时，UV吸收物质和ABA含量也得到积累。另一方面，增强UV-B对青杨两个种群各个指标的影响，同干旱所引起的效应有着相似的趋势。同低海拔种群相比，高海拔种群有着更强的抗旱和抗UV-B能力，具体表现在高海拔种群有着更多的生物量积累，更强的气体交换和水分利用效率及更高水平的ABA和UV吸收物质含量。相比干旱诱导的生物量积累和气体交换的降低，在干旱和增强UV-B两个胁迫同时作用于青杨时，这种降低表现的更为明显。显著的干旱和UV-B的交互作用还表现在WUEi, WUET, δ13C, 可溶性蛋白含量, UV吸收物质含量, ABA, 叶片和茎中的N含量以及C/N比中。 3. 经过一个生长季的试验观察，增强UV-B、外源ABA及两因子共同作用对青杨的生物量积累、气体交换、内源ABA和UV吸收物质含量、抗氧化系统以及碳、氮含量和碳/氮比均产生显著影响。本试验中，青杨的两个种群分别来自中国西南部的不同海拔地区，高海拔种群来自青海大通而低海拔种群来自四川九寨。外源ABA的胁迫为直接喷施ABA到青杨叶片，而增强UV-B胁迫是利用平方波系统分别保证青杨苗暴露于外界UV-B强度和两倍于外界UV-B强度下。 研究结果显示，增强UV-B显著的降低了两个青杨种群的株高、基茎、总叶面积和总生物量等生长指标，同时也导致其A、gs、E和叶片中碳含量的减少。而显著增加了SOD和过氧化物酶(GPx)活性水平，诱导了过氧化氢(H2O2)和MDA的显著增加，促进了UV吸收物质和不同器官中内源ABA含量的显著积累。另一方面，外源ABA引起了青杨光合同化速率的下降，SOD和GPx酶活性的增强，H2O2 和 MDA含量也表现出显著增加，同时，内源ABA含量得到显著累积。同低海拔种群相比，高海拔种群具有更加抗UV-B和外源ABA的特性。显著的UV-B和ABA的交互作用表现在A, E, SOD和GPx活性，以及叶片和根部的内源ABA等一系列指标中。在所有胁迫下，叶片中的碳和氮含量同其在茎和根中的含量显著相关，另外，叶片和茎中的氮含量同茎中的碳含量显著相关。 Sunlight is an indispensable environment factor for plants survival and development. Meanwhile, photosynthetic organisms need sunlight and are thus, inevitably, exposed to UV radiation. Especially for recent years, ultraviolet radiation, especially UV-B reaching the Earth’s surface increased because of depletion of ozone layer resulted from emission of NxO and CFC’s from human activities. On the other hand, the sensitivity of plants to UV-B radiation depends on the species, developmental stage and experimental conditions. In this experiment, two populations of Picea asperata Mast from different water background and two populations of Populus cathayana Rehder from different altitude background were selected as model plants to assess the effects of enhanced UV-B radiation. Morphological and physiological traits induced by enhanced UV-B in each plant species were observed and the different responses were discussed, furthermore the influences of drought and exogenous ABA on responses induced by enhanced UV-B were studied. The study could provide a strong theoretical evidence and scientific direction for the afforestation and rehabilitation of ecosystem. The results are as follows: 1. Different responses of two contrasting Picea asperata Mast. populations to enhanced ultraviolet-B (UV-B) radiation under well-watered and drought conditions were investigated. And the effects of enhanced UV-B on tolerance of drought were also observed in our study that the UV-B exposure may have alleviated some of the damage induced by drought. Two contrasting populations, originating from a wet and dry climate region in China, respectively, were employed in our study. Drought significantly decreased CO2 assimilation rate (A), stomatal conductance (gs) and effective PSII quantum yield (Y), while it significantly increased non-photochemical quenching (qN) and the activity of superoxide dismutase (SOD) in both populations. Compared with the wet climate population, the dry climate population was more acclimated to drought stress and showed much higher activities of SOD and ascorbate peroxidase (APX), and much lower levels of malondialdehyde (MDA) and electrolyte leakage. On the other hand, enhanced UV-B radiation also induced a significant decrease in the chlorophyll (Chl) content in both populations under well-watered conditions, and a significant increase in UV-absorbing compounds in the wet climate population. After one growing season of exposure to different UV-B levels and watering regimes, the increases in MDA and electrolyte leakage, as induced by drought, were less pronounced under the combination of UV-B and drought. In addition, an additive effect of drought and UV-B on A and gs was observed in the wet climate population, and on the activity of APX and qN in the dry climate population. 2. The significant effects of drought, enhanced UV-B radiation and their combination on Populus cathayana Rehd. growth and physiological traits were investigated in two populations, originating from high and low altitudes in south-west China. Our results showed that UV-B acts as an important signal allowing P. cathayana seedlings to respond to drought and that the combination of drought and UV-B may cause synergistically detrimental effects on plant growth in both populations. In both populations, drought significantly decreased biomass accumulation and gas exchange parameters, including A, gs, E and photosynthetic nitrogen use efficiency (PNUE). However, instantaneous water use efficiency (WUEi), transpiration efficiency (WUET), carbon isotope composition (δ13C) and nitrogen (N) content, as well as the accumulation of soluble protein, UV-absorbing compounds and abscisic acid (ABA) were significantly increased by drought. On the other hand, cuttings from both populations, when kept under enhanced UV-B radiation conditions, showed very similar changes in all above-mentioned parameters, as induced by drought. Compared with the low altitude population, the high altitude population was more tolerant to drought and enhanced UV-B, as indicated by the higher level of biomass accumulation, gas exchange, water-use efficiency, ABA concentration and UV-absorbing compounds. After one growing season of exposure to different UV-B levels and watering regimes, the decrease in biomass accumulation and gas exchange, induced by drought, was more pronounced under the combination of UV-B and drought. Significant interactions between drought and UV-B were observed in WUEi, WUET, δ13C, soluble protein, UV-absorbing compounds, ABA and in the leaf and stem N, as well as in the leaf and stem C/N ratio. 3. During one growing season, significant effects induced by enhanced UV-B radiation, exogenous ABA and their combination on biomass accumulation, gas exchange, endogenous ABA and UV-absorbing compounds concentrations, antioxidant system as well as carbon (C) content, nitrogen (N) content and C/N ratio were investigated in two contrasting Populus cathayana populations, originating from high and low altitudes in south-west China. Exogenous ABA was sprayed to the leaves and enhanced UV-B treatment was using a square-wave system to make the seedlings under ambient (1×) or twice ambient (2×) doses of biologically effective UV-B radiation (UV-BBE). Enhanced UV-B radiation significantly decreased height, basal diameter, total leaf area, total biomass, A, gs, E and carbon (C) content in leaves, and significantly increased activities of SOD and guaiacol peroxidase (GPx), hydrogen peroxide (H2O2) and malonaldehyde (MDA) content as well as the accumulation of UV-absorbing compounds and endogenous ABA concentrations among different organs in both populations. In contrast, exogenous ABA showed significant decrease in A and significant increases in activities of SOD and GPx, H2O2, MDA content and the endogenous ABA concentrations. Compared with the low altitude population, the high altitude population was more tolerant to enhanced UV-B and exogenous ABA. Significant interactions between UV-B and ABA were observed in A, E, activities of SOD and GPx, as well as in endogenous ABA in leaves and roots of both populations. Across all treatments, C and N content in leaves was strongly correlated with those were in stems and roots, respectively. Additionally, leaf and stem N content were significant correlated with stem C content.

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。

水库集水区水土保持与流域产水量——以密云水库上游潮白河流域为例

针对密云水库上游承德"21世纪水资源可持续利用项目"中水土流失治理后来水减少,加剧下游城市(北京)水资源供需矛盾的问题,探讨集水区减少水土保持用水,增加流域产水量,从而水资源在下游(首都圈)发挥最大效益的思路。在将流域分成3种类型区的基础上,提出了流域分区治理方案及其标准:1)生态产水功能区,以增加产水供给下游为主要目的,提出以需水量最低的低覆盖度草地配置为主的水土流失坡面治理模式和减少蓄水、增大拦沙的弱化与强化相结合的沟道治理模式;2)生产生活功能区,以满足流域基本粮食生产为主要目的,提出以黄土丘陵区坝地为主的水土流失治理模式及其标准;3)生态产水与生产生活复合功能区,兼顾二者功能,提出以需水量中等的灌木林和疏林配置为主的水土流失治理模式及标准。

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

土壤中施用聚丙烯酸钠保水剂对冬小麦生长及产量影响

聚丙烯酸钠因其特殊的保水性能受到广泛重视,但是其研究仍多限于实验室模拟研究。为了促进其在农业生产中的应用与推广,该文采用大田试验,研究了聚丙烯酸钠对冬小麦生长、产量及水分利用效率(WUE)的影响。结果表明施入聚丙烯酸钠能够促进小麦生长,提高小麦叶绿素含量,提高小麦产量与WUE。采用沟施5.5 m3/hm2的1/2000聚丙烯酸钠水溶液,能够使小麦较对照增产2.9%,WUE增加3.52 kg/(hm2.mm);与肥料混合使用时,增产效果更加显著,可增产10.14%,WUE增加4.38 kg/(hm2.mm)。

黄土高原丘陵沟壑区沟道水资源利用模式初探

黄土高原丘陵沟壑区干旱缺水 ,要让有限的水资源支撑当地的生态农业建设 ,就要高效利用有限水资源 ,提高单位水的利用效率。通过在延安市燕儿沟的生产实践证明 ,在沟道中兴建截潜流工程 ,引水上山 ,发展坡地果园和保护地蔬菜微灌 ,是高效利用当地有限水资源的一种重要模式 ,很有推广价值

不同倍性小麦材料对水分和密度条件的响应

以栽培一粒(2n)、栽培二粒(4n)和长武134(6n)为材料在大型活动防雨棚条件下研究不同倍性小麦材料在不同密度和水分条件下的产量适应性变化。结果发现,在两种水分条件下随着染色体倍性从2n→6n的增加,产量、千粒重、水分利用效率(WUE)和收获指数均呈增加趋势,在水分胁迫下各材料穗粒数和穗数则呈降低趋势,而在正常供水下穗粒数则呈增加趋势。在水分胁迫下栽培一粒、栽培二粒和长武134最高产量分别出现在中、低、高密度群体,而同一材料不同密度群体间变异系数分别为6.73%,1.98%,9.07%;不同倍性材料千粒重均随着密度增加而减小,而穗数则逐渐增加,二倍体的穗粒数以中密度最高,四倍体的穗粒数随着群体密度的增加而减小,六倍体则相反;三种材料WUE和收获指数分别以低、高、低密度最高。正常供水下随着染色体倍性从2n→6n的增加,三个倍性材料最高产量分别出现在高、低、低密度群体,而同一材料不同密度群体间变异系数分别为6.01%,17.12%,2.46%;千粒重表现为中密度>低密度>高密度,而穗粒数均以低密度群体最高,二倍体和四倍体以高密度群体最低,六倍体则以中密度群体最低,穗数则随着密度群体增加而增加;二倍体WUE以高...

土壤改良剂节水增产效应的田间试验研究

采用田间试验,探讨了施用土壤改良剂对冬小麦的产量及水肥利用效率的影响。结果表明,施加土壤改良剂能降低作物生育期耗水量,提高冬小麦的产量,增加水肥利用效率。在不灌水条件下,施加土壤改良剂1500kg/hm2,能够使冬小麦较对照增产15%,水分利用效率(WUE)提高了21.65%,磷肥利用效率(PUE)较单施磷肥增加2.92%。在灌水33.3mm的条件下,施加土壤改良剂较对照可增产28.57%,将土壤改良剂与磷肥混施增产可达到42.86%。而且,PUE较单施磷肥增加了11.11%,WUE达到25.06kg/(hm2·mm)。

黄土高原半干旱地区的农业发展与高效用水

黄土高原的大部分处于半干旱地带,属于生态环境脆弱地区,改善黄土高原地区的生态环境和提高生产力不仅是黄土高原地区内部的问题,而且是西部大开发的重要组成部分.本文在总结和对比分析国内外半干旱地区农业发展过程中的成功经验与关键措施的基础上,提出该地区的农业发展战略应该以实现水土资源高效利用和开发基因资源的潜力为目标.同时,针对黄土高原半干旱地区的农业水环境,论述了作物对有限水高效利用的原理,并对该地区农业可持续发展的技术对策提出了建议.

不同类型作物对干湿交替环境的反应

通过对干湿交替环境下春小麦、马铃薯、大豆和玉米等作物的产量、水分利用效率及光合作用、蒸腾作用、气孔导度等生理变化的研究表明 :( 1 )春小麦和马铃薯在干湿交替环境下可获得与充分供水相当的产量而它们的水分利用效率却显著提高 ,大豆减产幅度较大 ,玉米减产严重 ,其水分利用效率显著低于全湿处理 ;( 2 )浇水后各作物的光合速率、蒸腾速率和气孔导度都有所增加 ,但不同作物增加的幅度不同 ,就是同一作物各指标的增幅也不同 ;( 3)干湿交替环境下同化物的运输模式有利于春小麦籽粒的充实和马铃薯块茎的膨大 ,而不利于玉米产量的形成 ;( 4 )产量不仅决定于营养生长阶段 ,更主要决定于生殖生长阶段。此外 ,还就干湿交替过程中若干生理变化和经济产量形成机制作了初步探讨。

水分和氮磷水平对小麦碳同位素分辨率和水分利用效率的影响

依据盆栽试验数据 ,利用植物稳定性碳同位素分辨率的理论模型 ,研究了水分和氮磷营养对小麦叶片碳同位素分辨率 (Carbon- isotope discriminationΔ)的影响。结果表明 :水分差异引起碳同位素分辨率较大变异 ,碳同位素分辨率随土壤相对含水量 (Soil relative water content)的提高而提高 ,在土壤相对含水量为 6 0 %～ 70 %条件下碳同位素分辨率最高。缺水时磷水平提高 ,碳同位素分辨率提高。水分利用效率 (Water use efficiency)与碳同位素分辨率关系受土壤水分和养分水平的影响。缺水条件下水分利用效率与碳同位素分辨率之间为负相关 ,充分供水下为正相关 ;在低氮水平下的关系不明显 ,施氮 15 0 kg· hm- 2时相关性显著。

林地施肥与水肥效益

概述了国内外林地施肥的现状 ,简要论述了氮肥利用效率和水分利用效率在农林业生产中的意义。同时 ,阐述了水肥耦合的研究状况 ,并说明了水肥耦合理论应用于林业生产中以改善黄土高原因水肥不协调而形成大面积低效林的重要意义

陕北丘陵沟壑区坡地不同耕作法综合效益研究

以在陕北丘陵沟壑区坡耕地不同耕作法试验 7a的资料为依据 ,论述了不同耕作法的水分利用、土壤水分平衡及单位面积产量和水土保持等综合效益。作物生长主要依赖生育期内自然降雨 ;作物耗水量与每年生育期降雨量及土壤供水量呈显著正相关 ,不同耕作法之间变化不大 ,作物主要利用 0— 12 0 cm土层内的水分。同一年内不同耕作法的综合效益从优到劣、由高到低的排列顺序为宽梯田 >窄梯田 >水平沟 >平播 >水平阶 >隔坡梯田。而水土保持效益排列顺序为 :梯田 >水平沟 >隔坡梯田 >水平阶 >平播 >裸地。认为坡耕地确实应尽快退耕还林还草 ,以加速陕北生态环境建设 ,推进农业结构的战略性调整。