摘要
研究了150mmol·L-1NaHCO3胁迫下,不同浓度硝酸镧对黑麦草幼苗光合作用、叶绿素荧光参数、Mehler反应,以及叶黄素循环的影响.结果表明:低浓度硝酸镧(0.05mmol·L-1)叶面喷施处理能显著减小NaHCO3胁迫下黑麦草叶片净光合速率(Pn)、气孔导度(Gs)、蒸腾速率(Tr)、气孔限制值(Ls)的下降幅度和胞间CO2浓度(Ci)的上升幅度,有效缓解NaHCO3胁迫对叶片PSⅡ光化学猝灭(qP)、实际光化学效率(ΦPSⅡ)、依赖光合碳同化电子传递(ETRp)和依赖Mehler反应电子传递(ETRm)的抑制,增强黑麦草叶片中超氧化物歧化酶、过氧化物酶和抗坏血酸过氧化物酶的活性,提高非光化学能量耗散(NPQ)、叶黄素循环库(V+A+Z)和脱环氧化程度(A+Z)/(V+A+Z),从而减轻NaHCO3胁迫对光合机构的伤害;但高浓度硝酸镧(0.5mmol·L-1)对NaHCO3胁迫伤害的缓解效果不明显.表明适宜浓度的硝酸镧能够缓解NaHCO3胁迫下非气孔因素引起的黑麦草叶片光合速率下降以及对光化学效率的抑制,并通过促进Mehler反应直接耗散过剩激发能和激活依赖叶黄素循环的热耗散,保护NaHCO3胁迫引起的过剩光能对光合机构造成的伤害,而Mehler反应加强所产生的活性氧可被抗氧化酶活性的提高所清除.
This paper studied the effects of foliar spraying different concentration La（NO3） 3 on the photosynthesis,chlorophyll fluorescence parameters,Mehler reaction,and xanthophyll cycle of ryegrass seedlings under the stress of 150 mmol NaHCO3·L-1.Foliar spraying low concentration（0.05 mmol·L-1） La（NO3） 3 could significantly decrease the decrement of net photosynthesis rate（Pn）,stomatal conductance（Gs）,transpiration rate（Tr）,and stomatal limited value（Ls） and the increment of intercellular CO2 concentration（Ci） under NaHCO3 stress,efficiently alleviate the inhibitory effects of NaHCO3 stress on PSⅡ photochemical quenching（qP）,actual photochemical efficiency（ΦPSⅡ）,photosynthetic carbon assimilation-dependent electron transport rate（ETRp）,and Mehler reaction-dependent electron transport rate（ETRm）,enhance the activities of superoxide dismutase,peroxidase,and ascorbate peroxidase,the non-photochemical energy dissipation（NPQ）,the xanthophyll cycle pool（V ＋ A ＋ Z）,and the de-epoxidation extent of xanthophyll cycle（A ＋ Z） /（V ＋ A ＋ Z）,and thereby,alleviate the damage of photosynthetic apparatus caused by NaHCO3 stress.However,treating with high concentration（0.5 mmol·L-1） La（NO3） 3 had no obvious alleviation effects.It was suggested that foliar spraying an appropriate concentration La（NO3） 3 could not only alleviate the decrease of ryegrass seedling＇s photosynthetic rate induced by non-stomata factors and the inhibition of photochemical efficiency,but also accelerate the Mehler reaction under NaHCO3 stress.With the accelerated Mehler reaction,excessive excitation energy could directly be consumed,and the xanthophyll cycle-dependent thermal dissipation could be promoted to efficiently protect the photosynthetic apparatus against photo-damage under NaHCO3 stress.Also,the active oxygen produced by the accelerated Mehler reaction could be scavenged by the enhanced anti-oxidative enzyme activities.
出处
《应用生态学报》
CAS
CSCD
北大核心
2010年第11期2836-2842,共7页
Chinese Journal of Applied Ecology
基金
甘肃省科技支撑计划项目(GK098-1-34)
甘肃省庆阳市科技攻关计划项目(0802NKCM082)资助
