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以玉米品种郑单958(抗旱性强)和陕单902(抗旱性弱)为材料,采用抗旱池栽控水试验,研究了2个品种叶片光合特性、保护酶活性以及干物质转运对吐丝期干旱胁迫的响应。结果表明,在吐丝期干旱胁迫下2个品种产量分别降低39.10%和44.87%;叶片净光合速率(Pn)和气孔导度(Gs)显著下降,胞间CO2浓度(Ci)先升后降。PSII最大光化学效率(Fv/Fm)、实际量子产额(ΦPSII)、光化学猝灭(qP)降低,非光化学猝灭(qN)升高;抗氧化酶(SOD、POD和CAT)活性先升高后降低,而丙二醛(MDA)含量一直升高。吐丝期干旱胁迫增加了花前营养器官贮藏同化物转运量(率)及其对籽粒转运的贡献率;但郑单958受干旱影响程度小于陕单902。抗旱品种郑单958具高抗氧化酶活性清除活性氧,使得膜脂过氧化程度轻,维持较高的光化学效率,延长叶片光合功能期,促进花前营养器官贮藏同化物转运量对籽粒的贡献率。这可能是其在干旱胁迫下仍能获得较高产量的重要原因之一。
Taking the maize varieties Zhengdan 958 (strong drought resistance) and Shaandan 902 (weak drought resistance) as materials, the photosynthetic characteristics, activities of protective enzymes and the activities of dry matter translocation on silking Response to drought stress. The results showed that the yield of two cultivars decreased by 39.10% and 44.87%, respectively, under drought stress in silking stage. The net photosynthetic rate (Pn) and stomatal conductance (Gs) of leaves decreased significantly and the intercellular CO2 concentration (Ci) . The maximum photochemical efficiency of PSII (Fv / Fm), the actual quantum yield (ΦPSII), the photochemical quenching (qP) and the non-photochemical quenching (qN) increased; the activity of antioxidant enzymes (SOD, POD and CAT) After the reduction, while the malondialdehyde (MDA) content has been increased. Drought stress during silking stage increased the amount of stored plant assimilates translocated and their contribution to grain transport; however, Zhengdan 958 was less affected by drought than Shaandan 902. Zhengdan 958, a drought-tolerant cultivar with high anti-oxidative enzyme activity, scavenged reactive oxygen species, made membrane lipid peroxidation light, maintained high photochemical efficiency, prolonged the photosynthetic functional period and promoted the contribution of stored vegetative assimilates to the grain rate. This may be one of the important reasons why it can still achieve higher yield under drought stress.