不同浓度的硝酸盐对高蛋白小麦幼苗叶片叶绿素荧光参数的影响

以两组产量水平相近而蛋白质含量有较大差异的四个小麦品种为试材, 研究了苗期不同浓度的硝酸盐对叶绿素荧光参数Fv/Fm和ΦPSII日变化的影响. 结果表明: 在中午强光下, 缺氮处理(无NO3-)和CK(15 mmol L-1 NO3-, 15N)中四品种的Fv/Fm、ΦPSII都有所下降, 缺氮处理中二者的下降幅度显著高于CK; 高蛋白小麦PH82-2-2和PH85-16下降     

盐处理下两种砧木对甜樱桃‘萨米脱’光合影响的比较

在不同浓度NaCl处理下,测定了以‘吉塞拉5号’（G5）、B5为砧木的甜樱桃‘萨米脱’光合和叶绿素荧光参数。结果表明：盐胁迫下,两种砧木嫁接的‘萨米脱’叶片的Pn、Gs、Fv/Fo、ΦPSII和ETR值随着处理浓度的增加或处理时间的延长显著下降,适度盐胁迫对‘萨米脱’叶片的光合抑制主要是气孔限制（3‰和6‰ NaCl）,高盐胁迫主要为非气孔限制（9‰ NaCl）。两种砧木对所嫁接的‘萨米脱’光合影响效应因盐胁迫程度而异,适度盐胁迫下,以G5为砧木的Pn、Gs、Fv/Fo、ΦPSII和ETR值较以B5为砧木的下降时间晚且降幅小,但在高盐胁迫下则反之。     

盐胁迫下水稻叶绿素荧光特性与离子积累的相关性分析

以4个北方常规粳稻品种为材料,于孕穗期施加80 mmol/L的NaCl胁迫,测定了水稻叶片叶绿素荧光参数及体内离子含量的变化,以揭示盐胁迫下水稻离子积累与叶绿素荧光特性的相关性.结果表明,盐胁迫下水稻叶片最大荧光(Fm)、最大光化学量子效率(Fv/Fm)、光系统II的实际光合效率(PhiPSⅡ)、表观光合量子传递效率(...     

高温胁迫对蝴蝶兰幼苗叶绿素荧光参数的影响

为了探究高温胁迫对蝴蝶兰幼苗叶片光合机构的影响,将蝴蝶兰幼苗置于38℃处理4天,以25℃为对照,测定了蝴蝶兰幼苗叶绿素荧光参数的变化。结果表明：随着高温胁迫时间的延长,蝴蝶兰叶片叶绿素总含量、最大光化学效率(Fv/Fm)、有效光量子产量(ΦPSⅡ)、表观光合电子传递速率(ETR)、光化学猝灭系数(qP)持续下降,而丙二醛(MDA)含量、初始荧光(Fo)、非光化学猝灭系数(qN)不断上升。与胁迫前相比,胁迫后期的上述指标均存在显著差异。由此表明,高温胁迫下蝴蝶兰幼苗PSⅡ反应中心出现了可逆失活或损伤,使光合原初反应过程受阻,显著降低了原初光能转换效率,从而引起严重的光抑制,极大地减弱了光合电子传递活性,使反应中心积累过剩光能,对光合机构和叶绿素造成光氧化破坏,但蝴蝶兰幼苗能在一定程度上通过热耗散途径来减轻伤害。     

外源硅对盐胁迫下黄果厚壳桂幼苗的光合荧光及抗氧化特性的影响

为探讨外源硅对盐胁迫下黄果厚壳硅的缓解作用。以一年生黄果厚壳桂(Cryptocarya concinna)幼苗为材料,在100 mg/L NaCl胁迫下,添加不同浓度(0、0.5、1、2 mmol/L)外源硅对幼苗进行处理,测定和分析不同处理下幼苗叶片的叶绿素含量、光合、叶绿素荧光特性参数和抗氧化酶含量。结果表明,外源硅能不同程度提高Pn、Tr、Gs、Fv/Fm,降低Ci;提高叶绿素a、叶绿素b和类胡萝卜素含量;提高SOD、PPO和APX活性,降低MDA含量。其中PPO在1.0 mmol/L硅处理下效果最佳,其他指标均在 2.0 mmol/L硅处理效果最佳。可见,添加适度浓度硅可以缓解盐胁迫对黄果厚壳桂幼苗的伤害,提高其耐盐能力,该研究为黄果厚壳桂引种栽培提供参考。     

持续干旱对油棕幼苗叶绿素荧光动力学参数的影响

为研究持续干旱对油棕叶绿素荧光动力学参数的影响,以油棕2 年生幼苗为试验材料,采用盆栽方式模拟自然持续干旱,测定叶绿素荧光参数及叶绿素含量,并运用隶属函数法对其抗旱性进行综合分析。结果表明：干旱胁迫下,油棕叶片叶绿素含量、可变荧光(Fv)、最大荧光(Fm)、可变荧光与最大荧光比(Fv/Fm)均降低;初始荧光(F0)和非光化学淬灭系数(NPQ)则升高,说明干旱胁迫伤害了光系统Ⅱ(PSⅡ),使得PSⅡ原初光能转换效率(Fv/Fm)降低,光合电子传递、光合原初反应过程受到抑制,起光保护作用的热耗散(NPQ)提高。4 个品种的叶绿素荧光参数和叶绿素含量的变化存在品种间差异,整个处理过中对干旱的适应性‘热油6号’＞‘热油8号’＞‘热油2号’＞‘热油4号’,因此,叶绿素荧光参数和叶绿素含量可作为抗旱性强弱的诊断指标用于油棕抗旱育种及相关研究。     

Responses of Canopy Photosynthesis,Spectral Indices and Solar-Induced Chlorophyll Fluorescence in Cotton under Drought Stress

[Objective] Study canopy photosynthesis, spectral indices and solar-induced chlorophyll fluorescence in cotton under drought stress. [Method] Using transgenic cotton cultivar Nongda 601 as material, a two-year experiment was conducted with four irrigation regimes (CK, light drought, moderate drought and severe drought) under a field mobile shed to measure the following indices and parameters at canopy level: canopy photosynthetic rate (CAP), spectral indices (normalized difference vegetation index (NDVI), photochemical reflectance index (PRI) and water index (WI)) and solar-induced fluorescence at 761 nm (F761), as well as plant leaf water content (LWC) and leaf area index (LAI). [Result] The results indicated that LWC, LAI, CAP, NDVI, PRI and F761showed a downward trend along with the prolonging of the drought stress, while WI showed an increasing trend. Extremely significant differences (P＜0.01) were found among drought treatments and CK for all parameters. NDVI, PRI and WI were significantly correlated with LAI and LWC (P＜0.01). The absolute values of correlation coefficient for NDVI, PRI, WI, F761with LAI (|r|>0.6) were lower than those with LWC (|r|>0.8). F761 was better correlated with leaf water content and LAI than other spectral indices. [Conclusion] It was concluded that CAP, PRI, NDVI, WI and F761 are good indicators in cotton leaves during drought stress. Solar-induced fluorescence seems more sensitive to leaf water status than other spectral indices at canopy level in cotton.     

NMR Techniques Coupled with Multivariate Statistical Analysis: Tools to Analyse Oryza sativa Metabolic Content under Stress Conditions

Rice ( Oryza sativa L.) is one of the most important crops in the world and its growth is influenced by several environmental stresses, such as drought and high salinity. In our study, we first investigated the metabolic profile in shoots and roots of two rice cultivars (Arborio and Nipponbare) through ¹H-high-resolution magic angle spinning (HR MAS) and liquid-state nuclear magnetic resonance (NMR) experiments. Drought and salt stress experiments on shoot and root growth showed Arborio seedlings to be more sensitive than those of Nipponbare to these abiotic stresses. Moreover, the metabolic content of the same samples was analysed by liquid-state NMR coupled with multivariate statistical analysis. Principal component analysis highlighted a significant accumulation of amino acids and sugars in shoots and roots under stress conditions and the existence of clear differences between the two analysed rice cultivars. In particular, Arborio seedlings accumulated a higher concentration of amino acids and sugars than Nipponbare seedlings. Furthermore, we also obtained preliminary data about metabolic changes in rice following infection with the fungus Magnaporthe grisea . This study proves that NMR technique coupled with multivariate statistical analysis is a powerful tool to assess a possible correlation between differences in metabolic profile and in tolerance/sensitivity phenotype in rice cultivars.     

水分胁迫对甘薯叶绿素荧光和光合特性的影响

以甘薯品种皖84-559，徐州18，为材料，测定功能叶片的光合和叶绿素荧光参数的变化。水分胁迫下，徐州18叶绿素含量、光合速率、PSⅡ原初光化学效率（Fv/Fm）和光化学猝灭系数（qP）的下降较少；非光化学猝灭系数（qN）增加较少。表明徐州18在水分胁迫条件下，光合机构受破坏较轻，其吸收的光能能较多的用于光化学转化能力，通过热耗散的能量较少。     

NaCl胁迫对茄子幼苗叶片叶绿素荧光参数和能量分配的影响

以茄子幼苗为试材,研究了不同浓度NaCl胁迫下叶绿素荧光参数的变化.结果表明:随着NaCl胁迫加剧,最大荧光(Fm)、PSII最大光化学效率(Fv/Fm)、PSII潜在活性(Fv/Fo)、PSII实际光化学效率(ФPSII)、天线转化效率(Fv＇/Fm＇)、光化学荧光猝灭系数(qP)和电子传递速率(ETR)均表现出降低的趋势,初始荧光(Fo)、非光化学荧光猝灭系数(NPQ)和PSⅡ激发能压力(1-qP)均上升;光化学反应的能量(P)在叶片所吸收的光能中所占的比例也逐渐减少,天线色素耗散的能量(D)表现出和P相反的趋势,非光化学反应耗散的能量(E)变化不稳定,天线热耗散是耗散过剩能量的主要途径.表明NaCl胁迫下,茄子幼苗光系统反应中心受到损伤,光合电子传递过程受到抑制.     

花铃期干旱胁迫下氮素水平对棉花光合作用与叶绿素荧光特性的影响

于2004—2005在江苏南京农业大学卫岗试验站进行盆栽试验, 设置干旱与对照2个土壤水分处理, 每个处理再设置3个氮素水平, 研究了花铃期干旱胁迫下氮素水平对棉花叶片光合作用与叶绿素荧光参数的影响, 以期为棉花花铃期干旱时的合理氮肥运筹提供理论依据。结果表明, 与对照相比, 干旱处理显著降低了棉株凌晨叶水势、土壤相对含水量、净光合速率(P_n)、气孔导度(G_s)与胞间CO₂浓度(C_i), 但提高了叶绿素a(Chl a)、叶绿素b(Chl b)、总叶绿素(Chl a+b)及类胡萝卜素(Car)的含量。干旱处理下, P_n、G_s、C_i、Chl a、Chl b、Chl a+b及Car均以240 kg hm^-2氮素水平最高。干旱胁迫下叶绿素初始荧光(Fo)明显升高, 且随氮素水平的提高而增大; 而最大光化学效率(F_v/F_m)、光系统II(PS II)量子产量(ΦPS II)、电子传递速率(ETR)与光化学猝灭系数(qP)均显著降低, 干旱胁迫亦增大了非光化学猝灭系数(NPQ)。干旱胁迫下F_v/F_m、ΦPS II、ETR与qP均以240 kg hm^-2氮素水平最高。干旱胁迫显著降低叶片蒸腾速率(Tr), 导致叶温升高, 增施氮肥进一步增大了叶温。干旱胁迫降低了棉株各器官干物质重, 而施氮则增大水分胁迫指数。综合分析认为, 过量施氮或施氮不足均不利于提高棉花叶片光合性能。两年试验结果表明, 在本试验设置的3个氮素水平中, 花铃期干旱胁迫下以240 kg hm^-2纯氮, 且基施50%, 初花期追施50%较适宜。     

The Effects of Foliar Application of Ascorbic Acid (Vitamin C) on Antioxidant Enzymes Activities, Lipid Peroxidation and Proline Accumulation of Canola (Brassica napus L.) under Conditions of Salt Stress

The effects of salt stress on protein (PROT) content, lipid peroxidation, proline accumulation, chlorophyll (Chl) content, and superoxide dismutase (SOD; EC 1.15.1.1), catalase (EC 1.11.1.6) and peroxidase (EC 1.11.1.7) activity were studied in the leaves and roots of canola (Brassica napus L. cv. Okapi). Four weeks after sowing (at the V₄ stage), plants were exposed to salt stress by the application of NaCl solution (200 mm ) for 6 days daily, After 6 days followed by foliar application of ascorbic acid (AsA) solution (25 mm ). The activity of all the antioxidant enzymes assayed (except SOD in the roots) was increased significantly in the plants under conditions of salt stress. The application of AsA decreased enzyme activity in the leaves, but it had no effect on enzyme activity in the roots. The total PROT content of the leaves and roots decreased under the conditions of high salinity. AsA treatment of plants under salt stress increased the total PROT content significantly in both leaves and roots. Measurement of the malondialdehyde content of leaves and roots showed that lipid peroxidation was increased by interaction with damaging reactive oxygen species during salt stress, and that application of AsA reduced lipid peroxidation only in the leaves. The Chl content was also affected by salt stress. There was significant difference between the controls and salt‐stress treatments in Chl content. The results of the present study indicate that usage of AsA reduces the harmful effects of salinity and increases resistance to salinity in canola plant.     

低温弱光对两个西葫芦品种幼苗光合速率及叶绿素荧光参数的影响

以西葫芦进口品种元帅和地方品种X6-4为试材,研究了12℃低温和140 land/(m2·s)弱光同时处理对二者幼苗叶片净光合速率(Pn)及叶绿素荧光参数的影响.结果表明:低温弱光使两品种西葫芦幼苗Pn显著下降,元帅Pn的下降幅度较小,并在恢复生长12 d后基本恢复至对照水平;低温弱光胁迫条件下,两品种最大光化学效率Fv/Fm、有效光化学效率Yield、光化学淬灭系数qP及非光化学淬灭系数qN均有不同程度的下降,其中元帅的各项参数下降幅度较小且在恢复生长12 d后各参数均能恢复或接近对照水平.说明12℃低温140μmol/(m2·s)弱光条件下,元帅PSⅡ反应中心所受的伤害轻,反应中心进行光合作用的能力较高.     

Effects of Exposure to Short Periods of Suboptimal Temperature during Chill (5 °C) on Gas Exchange and Chlorophyll Fluorescence in Maize Seedlings (Zea Mays L.)

The effect of various periods of exposure to suboptimal temperature ('warm breaks'– WB: 14 °C for 4 h, 1 h and 0 h – control in 24 h cycles) during chilling (5 °C) of maize seedlings on the photosynthesis, the photochemical efficiency of photosystem II (Fv/Fm) and on the injuries of the cell membranes of leaves and water content in plants was compared. The measurements were conducted after 1, 3, 7 and 12 chill cycles. It was found that WB of either length distinctly diminished the chill-induced inhibition of net photosynthesis and the decrease of photochemical efficiency of PSII. The protective effect on WB on these parameters was observed shortly after completion of chilling of the plant as well as an after-effect. Daily warming up of the plants also reduced the leakage of electrolytes and diminished the water deficit of the chilled seedlings. The protective effect of WB on the measured parameters of the plants was greater in the chill-sensitive genotype than in the chill-tolerant one, especially when plants were warmed up for 4 h. The results obtained are an indication that short periods of warm weather during cold spring may diminish the injuries of the photosynthetic apparatus, as well as reduce the disturbance of water status of seedlings, contributing in this way to better condition of maize crops.