锰对大豆若干生理特性的影响

利用水培法研究锰对浙春2号和浙春3号大豆根系活力及叶片脯氨酸、丙二醛和蛋白质的影响。结果表明,适量锰处理可提高大豆根系活力,降低叶片中脯氨酸、蛋白质和丙二醛含量;锰过量,不利于大豆生长。两个大豆品种对锰的反应有差异,浙春3号对锰的敏感性大于浙春2号。     

高温胁迫对新疆榛光合参数和叶绿素荧光特性的影响

在5个温度梯度处理下,研究高温胁迫对4种新疆榛光合参数和叶绿素荧光特性的影响.结果表明:随着温度从25℃持续升高至45℃,新疆榛叶片的净光合速率、气孔导度、胞间CO2浓度、水分利用效率和光能利用效率逐渐降低,且在35～ 45℃之间降幅最大;光系统Ⅱ的实际光化学效率、电子传递速率和光化学猝灭系数随温度的升高缓慢上升,至35℃后急速下降;蒸腾耗水和热耗散随温度的升高而增大.4种新疆榛品种中,新榛3号的光合作用对高温的耐受力较高,属耐热性品种.     

不同菠菜品种对海水胁迫的生理响应差异

以耐海水菠菜品种荷兰3号和海水敏感品种圆叶菠菜为材料,采用水培方法,研究了海水胁迫对菠菜叶片、根系质膜的伤害作用以及叶片光合作用、叶绿素荧光参数的影响.结果表明:(1)海水胁迫对荷兰3号单株干重影响不大,而显著降低圆叶菠菜的单株干重,并使2个品种植株的叶片和根系MDA含量增加,质膜透性增大,叶片光合色素含量降低,但荷兰3号的变化幅度(叶片MDA除外)小于圆叶菠菜.(2)海水胁迫下,短期内2个品种由于气孔限制引起叶片胞间CO2浓度(Ci)降低,净光合速率(Pn)下降;长期胁迫下,荷兰3号Pn恢复到对照水平,而圆叶菠菜同化力下降,Pn降低.(3)海水胁迫对荷兰3号光化学猝灭系数(qP)影响不大,实际光化学效率(ΦPSⅡ)明显升高,而圆叶菠菜的qP和ΦPSⅡ均下降;荷兰3号初始荧光(F0)的下降幅度和非光化学猝灭系数(qN)上升幅度比圆叶菠菜大;2个菠菜品种的最大光化学效率(Fv/Fm)均下降,但荷兰3号光抑制程度(1-qP/qN)的升高幅度比圆叶菠菜小.研究结果说明,海水胁迫下,2个耐性不同的菠菜品种植株都产生了光合作用的光抑制和光氧化伤害,使膜质过氧化和叶绿素含量降低;耐性强的品种能够较多地将光能用于光化学反应,热耗散能力较强,光抑制程度较低,膜系统和光合色素受到活性氧的破坏程度较低,保持了较高的净光合速率,最终可明显降低海水胁迫对植株生长的影响.     

BTH和SA处理及白粉菌接种对甜瓜叶片光合特性的影响

以抗病品种Tam Dew和感病品种卡拉克赛为材料,研究了BTH和SA处理及白粉菌接种对甜瓜叶片叶面积、叶绿素含量、净光合速率、气孔导度、胞间CO2浓度的影响.结果表明,BTH和SA处理及白粉菌接种对甜瓜苗期叶面积扩展无显著影响;BTH和SA处理植株的叶片(第3叶)和新生叶片(第5叶)的净光合速率、叶绿素含量和气孔导度显著高于对照;白粉菌接种后,2个甜瓜叶片的叶绿素含量、净光合速率和气孔导度显著降低,而BTH和SA处理能缓解由白粉菌接种带来的叶绿素含量、净光合速率和气孔导度的下降趋势.说明BTH和SA处理能延长甜瓜叶片的光合寿命,延缓甜瓜叶片的叶绿素含量、净光合速率和气孔导度的下降趋势.     

水分胁迫对大果沙枣光合特性及生物量分配的影响

选取大果沙枣1年生幼苗,盆栽于相对含水量分别为70%~75%(CK)、50%~55%(T1)、35%~40%(T2)和15%~20%(T3)的土壤中培养25 d,研究大果沙枣在水分胁迫下的光合特性变化和生物产量积累及其分配规律。结果显示:水分胁迫抑制了大果沙枣的光合作用,与对照相比,T2和T3处理导致净光合速率、叶片蒸腾速率和水分利用效率显著降低,气孔阻力、胞间二氧化碳浓度和叶绿素含量升高,而且光合午休明显,非气孔因素是干旱时大果沙枣净光合速率下降的主要原因;水分胁迫下,大果沙枣的生长受到抑制,地上部分和地下部分的干生物量积累同时降低,但地下干生物量降低的程度低于地上部分;干旱处理中,T3处理显著抑制大果沙枣的生长,但仍保持一定的生物量增加。结果表明:大果沙枣具有一定的自我调节与保护能力,在水分胁迫下大果沙枣趋于将更多的资源分配给根系,以提高根冠比而适应干旱的环境。     

大豆幼苗对套作玉米遮荫环境的光合生理生态响应

以2个耐荫性不同的大豆品种为材料,田间试验设置大豆单作和玉米-大豆套作2个种植模式处理,研究不同耐荫性大豆品种的幼苗光合生理生态特性对套作玉米遮荫环境的响应。结果表明:1)玉米-大豆套作模式中,玉米遮荫显著降低大豆冠层的光合有效辐射,导致大豆幼苗光合速率、气孔导度、蒸腾速率显著下降(P0.05),分别达37.9%、54.2%和42.4%,但品种间无显著差异;而胞间二氧化碳浓度和Fv/Fm无显著变化,且光合速率的下降与气孔导度存在显著相关关系,光合速率下降主要是由气孔限制和CO2同化过程中能量不足所致;2)玉米遮荫显著降低大豆幼苗叶面积指数、叶片碳含量、叶片和根系干重及总生物量,且品种间差异显著,相关性分析显示,叶面积指数下降是导致生物量减少的主要原因;3)玉米遮荫环境中,大豆幼苗的叶片叶绿素和氮素含量提高以增强光捕获能力,但它们并不能补偿因光截获面积降低而引起的光截获量下降。     

NaCl胁迫抑制玉米幼苗光合作用的可能机理

用NaCl 100mmol/L处理玉米幼苗,216 h内不同时间分别测叶片光合速率及其它生理指标,结果表明随处理时间的延长,光合速率下降,气孔导度减小,细胞间隙CO2浓度先降低后升高(图1);叶片MDA(图5a)、Cl-、Pi(图4)及可溶性糖(图2b)含量增加;质膜透性增大(图2a);Chla/Chl b(图3b)及Fv/Fm(图5b)减小;MDH、PEPC酶活性降低(图6).细胞间隙CO2浓度的变化,说明光合速率下降的原因短时间内以渗透胁迫产生的气孔限制因素为主,长时间时以非气孔因素为主.Cl-多对细胞产生离子毒害,Pi的增多可竞争性地抑制RuBP羧化酶的活性.MDA的增加表明活性氧增多,活性氧通过使酶失活和膜伤害抑制细胞生长,使细胞内糖利用减少,可溶性糖含量增加,进而反馈性地抑制光合作用.活性氧还可以漂白叶绿素、增强光抑制及使与光合作用有关的酶失活,而抑制光合作用.因此,NaCl胁迫下光合作用降低的原因是多因素共同作用的结果,短时间内以气孔限制因素为主,长时间时以非气孔因素为主,在非气孔因素中活性氧的增加是主导因素.     

镉胁迫对不同甘蓝基因型光合特性和养分吸收的影响

以2个耐镉(Cd)性不同的甘蓝品种为材料,研究了不同Cd浓度(0、20、50、100μmol.L-1)对甘蓝植株生长、叶片光合特性和养分吸收的影响.结果表明:Cd敏感品种在低浓度Cd(20μmol.L-1)处理下生长受到明显抑制,叶片净光合速率(Pn)、气孔导度(Gs)、PSⅡ光化学效率(Fv/Fm)、PSⅡ光合电子传递量子效率(ΦPSⅡ)及地上部、根系干质量显著降低;Cd耐性品种在高浓度Cd(50和100μmol.L-1)处理下生长和光合特性受到显著影响;Cd胁迫降低了甘蓝叶片叶绿素a和b含量,尤其对叶绿素a的影响较大,进而抑制了叶片光合能力.Cd胁迫显著降低了植株对Mn的吸收,抑制了Mg和Fe从根部向地上部的转运,且Cd敏感品种受抑制幅度更大;Cd胁迫促进了Cd耐性品种对P和S的吸收,而Cd敏感品种相反.因此,Cd胁迫下甘蓝敏感品种叶片Mn、Fe、Mg、S和P含量的降低是影响其叶片光合作用,进而抑制植株生长的重要生理原因.     

不同浓度海水对油葵幼苗光合作用和叶绿素荧光特性的影响

采用砂培法,研究了不同浓度海水对油葵幼苗光合作用和叶绿素荧光特性的影响.结果显示:10%和20%海水处理下,油葵幼苗叶绿素含量、P n和ΦPSⅡ值较对照没有明显差异,表明较低浓度的海水处理对油葵幼苗光合作用没有明显影响;而30%和40%海水处理显著降低了油葵幼苗的叶绿素含量、P n、G s,同时还降低了叶绿素荧光参数F v/Fm、F v/F o、ΦPSⅡ和qP,表明高浓度海水处理抑制了油葵幼苗PSⅡ活性,降低了光合和碳同化能力,不利于幼苗的生长.此外,高浓度海水处理下油葵幼苗净光合速率的下降主要是气孔因素所致.     

遮荫对濒危植物甜菜树光合生理和叶绿素荧光特性的影响

以西南特有濒危植物甜菜树为材料,研究了不同遮荫处理(全光照、50％遮荫、65％遮荫和80％遮荫)对甜菜树叶片光合特性、叶绿素荧光和气孔特征的影响,为甜菜树种质资源保育和开发利用提供科学依据。结果表明：50％遮荫处理显著提高了甜菜树叶片净光合速率,80％遮荫处理则起抑制作用;50％遮荫和65％遮荫处理提高甜菜树叶蒸腾速率,有利于光合作用的进行;80％遮荫处理下胞间 CO 2浓度提高,抑制了甜菜树叶蒸腾作用和光合作用;50％遮荫和65％遮荫处理下净光合速率提高,说明甜菜树对遮荫有一定的适应性;叶绿素荧光方面,80％遮荫处理导致叶片 PSⅡ最大光化学效率(F v/F m )和实际光化学效率(ФPSⅡ)下降。甜菜树叶片光合特性与气孔结构关系密切,遮荫降低甜菜树叶片气孔密度。     

Effect of phosphorus deficiency on aluminium-induced citrate exudation in soybean (Glycine max)

Aluminium (Al) toxicity or phosphorus (P) deficiency can induce exudation of organic acids from the roots of some plants, which is believed to be a tolerance mechanism against Al toxicity or P deficiency. In the present study, the effect of P deficiency on Al-induced citrate exudation was investigated in three soybean varieties differing in low-P tolerance. P starvation alone failed to induce secretion of organic acids from all three soybean varieties. However, P deficiency altered Al-induced citrate exudation over time, showing a complex interaction. Short × term P starvation (4 days) produced up to 50% increase in Al-induced citrate secretion, while longer-term (10 days) starvation reduced Al-induced citrate secretion to trace amounts. However, after a further 1 day in complete nutrient solution for recovery, Al-induced citrate exudation from the recovered roots was approximately 6 times higher than that from the continuously P-starved plants, but still approximately 3.6 times lower than that from the P-sufficient control. With increasing P or Al supply, Al-induced citrate exudation increased, while Al accumulation in soybean roots decreased in parallel with the decrease of P supply. The photosynthetic rate, stomatal conductance and transpiration were decreased by P deficiency, whereas the intracellular CO₂ concentration was increased. These findings indicate that P nutrition has a significant effect on Al-induced citrate exudation and Al accumulation in soybean root apices.     

不同生育时期遮光对马铃薯光合特性和产量的影响

为了研究不同生育时期遮光对马铃薯光合特性和产量的影响,明确马铃薯不同生育时期对弱光的耐受性,对2个马铃薯品种(‘冀张薯12号'和‘冀张薯8号')进行了4个生育时期(苗期、苗期至现蕾期、现蕾期至开花初期、开花初期至收获期)和3个遮光度(不遮光对照、20%遮光率和50%遮光率)的处理试验。结果表明: 与不遮光处理相比,20%遮光率下,2个品种马铃薯苗期SPAD值显著降低,苗期至现蕾期、现蕾期至开花初期SPAD值无显著变化,开花初期遮光15 d可使SPAD值呈一定程度增加;50%遮光率下,2个品种马铃薯SPAD值变化趋势与前者相同,除开花初期增幅加大外,其他生育时期变化幅度接近。各时期遮光对马铃薯叶片气孔导度(g_s)影响不大,除50%遮光率下‘冀张薯8号'叶片g_s在开花初期较对照显著降低43.9%外,其他处理的g_s与对照均无显著差异。遮光后叶片胞间CO₂浓度(C_i)呈增加趋势,苗期、苗期至现蕾期50%遮光可使C_i显著增加,其余各时期的C_i无显著变化。4个时期遮光处理的叶片净光合速率(P_n)均降低,2个品种马铃薯叶片P_n在50%遮光处理下的降幅均大于20%遮光处理,‘冀张薯12号'除在苗期遮光处理的叶片P_n降幅大于‘冀张薯8号'外,其余时期的降幅均小于‘冀张薯8号'。4个时期遮光使马铃薯产量均降低,且50%遮光处理降幅大于20%遮光处理。‘冀张薯12号'在苗期不耐弱光,其余时期的耐弱光能力优于‘冀张薯8号'。综合分析表明,耐弱光能力强的品种遮光处理后,叶片P_n和g_s降幅小、C_i增幅小,产量降幅也小。     

不同蚕豆品种对铅污染的光合生理响应特征

以3个蚕豆品种(分别为K0883、K0502、K0697)为试验材料,通过大田模拟小剂量Pb污染(浓度为40和250 mg·kg^-1),研究了净光合速率、气孔导度、蒸腾速率、细胞间隙CO₂浓度、水分利用效率、叶绿素含量等光合生理响应特征的变化在不同品种中的差异.结果表明,Pb污染下3个蚕豆品种气孔导度和蒸腾速率没有显著变化,叶绿素含量有不同程度的上升;在250 mg·kg^-1 Pb浓度下,K0883蚕豆品种净光合速率、水分利用效率、细胞间隙CO₂浓度分别升高121.80％、上升193.70％、下降42.76％.3个蚕豆品种对Pb污染的抗性大小顺序为K0883＞K0697＞K0502.蚕豆不同光合生理指标对小剂量Pb污染的响应特征不同.不同蚕豆品种对小剂量Pb污染的响应特征存在差异,这种种内的差异性采用单个生理指标难以反映,只有通过对多个指标的整合分析才能表现出来.     

Response and tolerance of root border cells to aluminum toxicity in soybean seedlings

Root border cells (RBCs) and their secreted mucilage are suggested to participate in the resistance against toxic metal cations, including aluminum (Al), in the rhizosphere. However, the mechanisms by which the individual cell populations respond to Al and their role in Al resistance still remain unclear. In this research, the response and tolerance of RBCs to Al toxicity were investigated in the root tips of two soybean cultivars [Zhechun No. 2 (Al-tolerant cultivar) and Huachun No. 18 (Al-sensitive cultivar)]. Al inhibited root elongation and increased pectin methylesterase (PME) activity in the root tip. Removal of RBCs from the root tips resulted in a more severe inhibition of root elongation, especially in Huachun No. 18. Increasing Al levels and treatment time decreased the relative percent viability of RBCs in situ and in vitro in both soybean cultivars. Al application significantly increased mucilage layer thickness around the detached RBCs of both cultivars. Additionally, a significantly higher relative percent cell viability of attached and detached RBCs and thicker mucilage layers were observed in Zhechun No. 2. The higher viability of attached and detached RBCs, as well as the thickening of the mucilage layer in separated RBCs, suggest that RBCs play an important role in protecting root apices from Al toxicity.     

钼、硼对大豆叶片膜脂过氧化及体内保护系统的影响

The study deals with the changes of membrane peroxidation and endogenous protective system with different supplementation of molybdenum (Mo) and/or boron (B) concentration in soybean (Glycine max L.) leaves at three developmental stages (5-trifoliate stage, initiation of flowering, and peak podsetting stage) in three pot-grown soybean varieties (“Zhechun No.3”, “Zhechun No.2”, “3811”). The control plants under low Mo and low B exhibited an increasing of membrane permeability (MP), malondialdehyde (MDA) and proline (Pro) contents, polyphenol oxidase (PPO) and ascorbate oxidase (AO) activities and a decrease of ascorbate (AsA) contents, superoxide dismutase (SOD), peroxidase (POD), ascorbate peroxidase (AP) and catalase (CAT) activities. Application of Mo or B alone raised the ability of anti-oxidant of soybean leaves. The results indicated that the anti-oxidant enzymes (including SOD, POD, CAT and AP) related closely to anti-oxidant compounds (including AsA and Pro). There was some difference between the effects of Mo and B on the anti-oxidant, and a synergetic effect was observed between Mo and B. Some genetic variation in the responses to Mo and B was found among the three soybean varieties which was related to the activities of the total anti-oxidant systems.     

Xylem transport and shoot accumulation of lumichrome, a newly recognized rhizobial signal, alters root respiration, stomatal conductance, leaf transpiration and photosynthetic rates in legumes and cereals

* Root respiration, stomatal conductance, leaf transpiration and photosynthetic rates were measured in phytotron and field-grown plants following the application of 5 or 10 nM lumichrome, 10 nM ABA (abscisic acid) and 10 ml of 0.2 OD600 infective rhizobial cells. * Providing soybean and cowpea roots with their respective homologous rhizobia and/or purified lumichrome increased the concentration of this molecule in xylem sap and leaf extracts. Relative to control, rhizobial inoculation and lumichrome application significantly increased root respiration in maize, decreased it in lupin, but had no effect on the other test species. * Applying either lumichrome (10 nM), infective rhizobial cells or ABA to roots of plants for 44 h in growth chambers altered leaf stomatal conductance and transpiration in cowpea, lupin, soybean, Bambara groundnut and maize, but not in pea or sorghum. Where stomatal conductance was increased by lumichrome application or rhizobial inoculation, it resulted in increased leaf transpiration relative to control plants. Treating roots of field plants of cowpea with this metabolite up to 63 d after planting showed decreased stomatal conductance, which affected CO2 intake and reduction by Rubisco. * The effect of rhizobial inoculation closely mirrored that of lumichrome application to roots, indicating that rhizobial effects on these physiological activities were most likely due to lumichrome released into the rhizosphere.     

马铃薯/大豆套作对3个大豆品种光合指标和产量的影响

以大豆品种中黄30(早熟)、冀豆17(中熟)和齐黄34(晚熟)单作为对照,在大田条件下,研究马铃薯/大豆套作模式中3个品种生育期叶面积指数的变化及干物质积累的特征,分析套作马铃薯收获前后对大豆光合指标、产量及其构成因素的影响.结果表明： 生育前期阴蔽导致套作大豆叶面积指数(LAI)降低,干物质积累变缓,营养生长期相对延长,不同品种套作大豆光合速率(P_n)、蒸腾速率(T_r)和气孔导度(g_s)均低于单作.生育后期套作大豆生长加快,尤其是马铃薯收获后晚熟品种增幅显著提高.此时,套作大豆受光条件得到较大改善,表现出较强的补偿效应,LAI、干物质积累、P_n和g_s相对于单作上升幅度加大,接近于单作大豆,但不同品种补偿能力不同.与单作相比,套作模式下不同大豆品种的有效荚数、单株粒数及每荚粒数均有所降低,其中早熟品种分别显著下降22.0%、36.0%、17.6%,中熟品种下降5.1%、13.1%、8.9%,晚熟品种下降5.7%、7.6%、2.1%.套作模式下,中、晚熟大豆品种的产量较早熟品种分别高92.4%和163.4%,总土地当量比(LER)分别达到1.81和1.84.表明中、晚熟大豆品种与马铃薯组合套作优势更强,有利于马铃薯收获后大豆的补偿生长,促进套作大豆产量提高,充分发挥了复合群体的产量优势.     

Responses of Photosynthetic Rate and Stomatal Conductance to Water Stress in Soybean Leaves

Responses of photosynthetic rate and stomatal conductance to water stress as weI1 as the relationship between photosynthetic rate and stomatal conductance were investigated with soybean cultivars “Ludou No. 4” and “7605”. The former was a high yield cultivars widely used in Shandong province, and the latter was a small grain soybean line bred by Shandong Academy of Agricultural science. Soil water stress decreased leaf apparent photosynthetic rate and stomatal conductance of two soybean cultivars, and “Ludou No. 4” decreased more than “7605”. At the same value of water potential, photosynthetic rate and stomatal conductance of “7605” were higher than those of “Ludou No,4”,but the rate of stomatal closure for “7605” was higher than “Ludou No. 4”. Decreasing of stomatal conductance caused rising of leaf temperature of two soybean cultivars, and the rising of “7605” was more rapid than “Ludou No. 4”, but at the same treatment of water stress, leaf temperature of “Ludou No. 4” was higher than “7605”. Leaf water use efficiecy (WUE) of two soybean cultivars were decreased under water stress, and the rate of decreasing in “Ludou No.4” was more rapid than in “7605”. These results showed that “7605” was more resistant to water:stress than “Ludou No. 4”.     

Genotypic variation in the photosynthetic competence of Sorghum bicolor seedlings subjected to polyethylene glycol-mediated drought stress

Eleven varieties of Sorghum bicolor, subjected to PEG-mediated drought stress were compared for their photosynthetic performance. The varieties differed in their relative water content over a range of PEG concentrations (0-25%). CO2 assimilation, stomatal conductance and the quantum yield of PSII electron transport decreased with increasing PEG concentrations in all varieties. However the intercellular CO2 concentration showed a nonlinear PEG concentration-dependent change. At lower PEG concentrations there was a decrease in the levels of intercellular CO2 concentration in all varieties that could be attributed to stomatal closure. At higher PEG concentrations, some varieties showed an increase in the intercellular CO2 concentration, indicating an inhibition of photosynthetic activity due to non-stomatal effects, while others did not. It was seen that the varieties differed in the stress thresholds at which stomatal and metabolic limitations to photosynthesis occur. These differences in the photosynthetic adaptation of Sorghum varieties could be useful in identifying genotypes showing large differences in photosynthetic adaptation, which could be useful in mapping photosynthetic traits for drought stress tolerance.