扁核木光合特性的研究

用Li-6400光合作用测定系统对扁核木的光合特性进行了测定。结果表明：扁核木叶片光合速率日变化呈双峰曲线,最高峰分别出现在10：00和15：00,有明显的光合“午休”现象;叶片蒸腾速率和气孔导度的日变化趋势与光合速率相似,呈双峰曲线。光合速率与气孔导度、蒸腾速率呈极显著正相关;影响光合作用的主导环境因子为光合有效辐射和相对湿度。扁核木光合作用的光饱和点和补偿点分别为1020μLmol·m^-2·s^-1和23．8μLmol·m^-2·s^-1,表观量子效率为0．0569;CO2饱和点和补偿点分别为1330μLmol·mol^-1和54．7μLmol·mol^-1,羧化效率为0．0724;光合作用最适温是24．9℃。扁核木净光合速率的季节性变化也呈双峰曲线。     

土壤容重对玉米光合特性的影响及调控研究

以耕地棕壤为试验材料,采用盆栽方法,研究不同土壤容重对玉米光合指标(光合速率、气孔导度、胞间二氧化碳浓度)及叶绿素(a、b)的影响,并进一步研究了施用不同有机肥量及模拟不同耕作深度对玉米光合指标的调控效果。结果表明:不同容重处理之间对玉米叶绿素含量的影响拔节期前差异不显著,拔节期后达极显著差异(p<0.01),叶绿素含量在研究的生育期内始终增长。光合速率与容重、胞间二氧化碳浓度呈负相关,与气孔导度呈正相关。高容重土壤有机质调节至40～50 g kg-1即可以获得比较理想的效果;低容重的土壤有机质在研究含量范围内效果始终显著增长,有机质含量在15 g kg-1左右制约玉米生长,有机质含量应至少调节至3%以上。耕层厚度增加能提高所测定生理指标,但耕层厚度处理对叶绿素、光合指标影响不显著,当耕层厚度调节至30～40 cm时,各项指标增加基本达到限值,再增加耕层厚度作用不再明显。     

光氧化条件下两个水稻品种光合电子传递和光合酶活性的变化

在低ＣＯ２、低ＣＯ２、中等光强的光氧化条件下,测定了耐光氧化品种０２４２８和对光氧化敏感品种金刚３０的光合电子传递和碳代谢有关的酶活性变化。处理１天后,当耐光氧化品种ＰＳⅡ活性开始下降时,ＰＳⅠ活性有增加现象。随着叶内活性氧产生增加,两个品种的ＲｕＢＰｃ活性受到明显抑制,但耐光氧化品种的碳酸酐酶（ＣＡ）和磷酸烯醇式丙酮酸羧化酶活性出现诱导性增加。上述结果表明：在光氧化逆境下,光俣电子传递和碳同化的     

冬小麦对不同土壤水分的生理和形态响应

采用深桶栽培结合测坑法，从冬小麦反青至蜡熟期保持不同的土壤水分，分生育期对小麦的形态、生理和根系进行了测定。结果表明：调控土壤水分可明显改变冬小麦根、冠生长量比率。适宜的土壤水分胁迫（田持的５０％－６０％）可促进冬小麦根系发育，高土壤水分更有利于地上部生长。土壤水分长期低于田间持水量的６０％时，较显著地叶片的增大，从而减小截获光能的总叶面积，最终降低生物学产量和经济产量。土壤水分由“田持”的４６％升高到５５％，光合速率增幅不大，由５５％提高到６４％，光合速率出现跃迁式增高，土壤水分超过６４％后，光合速率几乎为等值。说明光合作用对土壤水分存在一个“阈值”反应，此值为土壤田间持水量的６５％左右。冬小麦的蒸腾速率随土壤水分递增而一直递增；综合考虑蒸腾速率与光合速率及水分利用效率之间关系，可以得出高土壤水分条件下冬小麦存在奢侈蒸腾耗水现象。     

北方烟区水肥一体化对烤烟生长、根系形态、生理及光合特性的影响

干旱抑制北方烟区烤烟的生长发育,造成烟叶产量、质量下降。为探讨北方烟区水肥一体化对烤烟田间生长、根系形态生理和光合特性的影响,以‘云烟87’为试验材料,研究了烤烟农艺性状、干物质积累量、根系形态和生理活性、光合作用、叶绿素荧光特性以及烤后烟叶经济性状在水肥一体化和沟灌常规施肥2个不同处理下的差异。结果显示,与沟灌常规施肥处理相比,水肥一体化能够促进烤烟生长发育,使田间农艺性状表现良好。水肥一体化能够明显提高根系和地上部干物质积累量,降低根冠比,显著增加根系体积、总吸收面积、活跃吸收面和比表面积以及根系活力、ATPase等相关根系形态和生理活性(P0.05)。在水肥一体化下,烤烟叶片的光合作用指标净光合速率(P_n)、气孔导度(Gs)、胞间CO_2浓度(C_i)和水分利用效率(WUE)以及叶绿素荧光参数PSⅡ最大光化学效率(Fv/Fm)、实际光化学量子效率(ΦPSⅡ)和光化学淬灭系数(q_p)均显著高于沟灌常规施肥(P0.05),而蒸腾速率(T_r)、非光化学淬灭系数(NPQ)则明显较低(P0.05);同时,其烤后烟叶的经济性状显著高于沟灌常规施肥处理(P0.05)。研究表明,水肥一体化可以创造良好的根系形态,提高根系生理活性,增强光合作用和光能利用效率,从而促进烤烟生长发育,有助于提高烤后烟叶的经济性状。     

单色绿光环境对孵化中种蛋蛋壳理化特性的影响

蛋壳是鸡胚发育过程中与外界环境进行气体和热量交换的重要媒介,其结构、形态等因素均为影响鸡胚发育的重要因素。单色绿光照射可缩短种蛋孵化时间,促进出雏、提高种蛋孵化率。有鉴于此,该研究针对单色绿光调控孵化过程中的种蛋蛋壳色度、蛋壳结构、色素含量及元素含量等因素进行监测,从种蛋蛋壳特性变化的角度探究单色绿光在种蛋孵化过程中促进雏鸡出雏的机制。结果表明,与传统黑暗孵化环境相比较,孵化过程单色绿光形成的光环境促使蛋壳对孵化环境产生适应性响应,蛋壳表面亮度显著降低（P<0.01）,抑制了蛋壳中绿色色素-胆绿素的分解（P<0.01）。且单色绿光有助于鸡胚吸收利用蛋壳中的Ca元素,显著促进孵化过程中蛋壳表面孔隙面积的风化增大（P<0.000 1）,提高蛋壳的通透性及散热效果,利于出雏期间雏鸡出壳,有助于促进出雏并降低孵化死亡率。该研究阐析了单色绿光孵化过程中种蛋蛋壳特性的变化,为单色绿光促进种蛋出雏及其在孵化产业的应用奠定了一定的理论基础。     

Colonization with endo-mycorrhiza affects the resistance of safflower in response to salinity condition

Two Safflower (Carthamus tinctoriusL.) cultivars' seeds were used to study the influence of inoculation with mycorrhiza arbuscular fungi under salinity stress condition. Factorial experiment based on completely randomized design (three-way analysis of variance (ANOVA)) with 3 replications was used. Salinity treatment with 3 levels (0.5, 6, and 12 dS/m) and mycorrhizal arbuscular inoculation with two species (three levels consist of non-inoculation, and inoculation with Glomus intraradices and G. moseae) were applied on two cultivars of safflower (Goldasht and Padide) in this experiment. Some important biochemical, mineral, and growth traits were measured in this study. Salinity had a significant negative effect on all growth and morphological parameters including shoot and root dry weight, stem and root height. On the other hand, colonized plants showed better growth parameters under saline conditions compared with the control. The colonization of both mycorrhizal species decreased with salinity. Sugar and pigment content decreased with salinity, but their levels in colonized plants under saline conditions were higher than that in non-colonized plants. Mineral elements including phosphorus (P), nitrogen (N), and magnesium (Mg) were higher in colonized plants, while salinity decreased the absorption of these elements in both inoculated and non-inoculated plants. Higher activity of the enzymatic antioxidant means higher removal of these compounds and higher resistance to stress condition. Overall, it is clear that salinity had a negative effect on both cultivars of safflower, but these negative effects were lower in inoculated plants than in the non-inoculated ones; so, the use of mycorrhizal inoculation is a proper way to control the effect of salinity and maintain plant production.     

高温对茶树叶片光合及抗逆特性的影响和恢复*3

以4个茶树品种福鼎大白茶、鸠坑、龙井43和乌牛早7a生植株为研究对象,采用人工气候箱模拟高温（35℃和40℃）处理6、12、18、24、48h,取出后置于人工气候箱中（25℃）恢复3、6、9d,以未经高温处理置于人工气候箱中（温度25℃）的各品种茶树为对照（CK）,测定茶树叶片的最大净光合速率、荧光参数、抗氧化酶活性以及细胞伤害率。结果表明：高温胁迫显著抑制了茶树的最大净光合速率（Pnmax）和最大光化学效率（Fv/Fm）,处理时间越长、温度越高,Pnmax和Fv/Fm下降越快,除35℃处理的福鼎大白茶外,其它3种茶树经过高温处理后,在恢复期间其Fv/Fm无法恢复至正常水平;茶树叶片的SOD酶活性在高温处理的前12h迅速上升,随着处理时间的延长,其活性降低;叶片MDA含量的平均值在高温处理第48小时达到最大,恢复期间缓慢下降;随着处理温度的升高和处理时间的延长,各茶树叶片的细胞伤害率均呈增加趋势。4种茶树耐热性的强弱由高到低依次为福鼎大白茶＞乌牛早＞鸠坑＞龙井43。     

棉酚及色素腺体对棉花抗枯萎病性的作用

本文对低酚棉与有酚棉的抗病和感病品种及其杂交后代进行了研究。结果表明，在种子中棉酚含量及色素腺体密度与品种的抗枯萎病性没有相关性。在幼苗中，低酚棉幼苗棉酚含量均显著高于有酚棉品种，但它们之间的抗枯萎病性也没有显著差异。在低酚棉与有酚棉品种杂交的Ｆ２代群体中，无色素腺体和稀色素腺体类型苗的抗病性明显高于腺体密度较高的类型苗。对７个杂交组合Ｆ２代中有色素腺体和无色素腺体幼苗的抗病性分析表明，无色素腺体类型苗的病指显著低于有色素腺体类型苗的病指。幼苗人工接种枯萎菌后，棉酚含量表现升高，但抗病品种低于感病品种。     

Photosynthetic pigments in soils from northern Victoria Land (continental Antarctica) as proxies for soil algal community structure and function

Although soil algae are among the main primary producers in most terrestrial ecosystems of continental Antarctica, there are very few quantitative studies on their relative proportion in the main algal groups and on how their distribution is affected by biotic and abiotic factors. Such knowledge is essential for understanding the functioning of Antarctic terrestrial ecosystems. We therefore analyzed biological soil crusts from northern Victoria Land to determine their pH, electrical conductivity (EC), water content (W), total and organic C (TC and TOC) and total N (TN) contents, and the presence and abundance of photosynthetic pigments. In particular, the latter were tested as proxies for biomass and coarse-resolution community structure. Soil samples were collected from five sites with known soil algal communities and the distribution of pigments was shown to reflect differences in the relative proportions of Chlorophyta, Cyanophyta and Bacillariophyta in these sites. Multivariate and univariate models strongly indicated that almost all soil variables (EC, W, TOC and TN) were important environmental correlates of pigment distribution. However, a significant amount of variation is independent of these soil variables and may be ascribed to local variability such as changes in microclimate at varying spatial and temporal scales. There are at least five possible sources of local variation: pigment preservation, temporal variations in water availability, temporal and spatial interactions among environmental and biological components, the local-scale patchiness of organism distribution, and biotic interactions.