缺磷条件下不同磷效率水稻品种光合特性和细胞保护酶活性

以6个不同磷吸收效率粳稻品种为材料,研究了缺磷条件下各种磷效率类型水稻品种的光合特性和细胞保护酶活性.结果表明:缺磷条件下,随着植株生长进程,不同磷效率水稻品种的光合速率(Pn)和可溶性蛋白质含量(pro)均不断下降;与丰磷处理相比,缺磷处理各测定时期的Pn和pro均有所降低.不同磷效率水稻品种中,磷高效品种的Pn(10.06～10.83μmolCO2.m-2.s-1)、叶绿素含量(3.32～3.56mg.g-1FM)和pro(33.08～33.95mg.g-1FM)最高,磷中效品种次之,磷低效品种最低;不同品种的气孔导度(Gs)差异不明显.随着磷胁迫时间的延长,各品种的超氧化物歧化酶(SOD)活性降低,表现为磷高效品种>中效品种>低效品种;各品种丙二醛含量的变化趋势与SOD活性相反;而过氧化物酶(POD)活性的变化规律不明显.因此,缺磷条件下,较高的SOD活性和较低的细胞膜脂过氧化程度在改善磷高效品种的光合生理功能中具有重要作用.

Photosynthesis and active-oxygen-scavenging enzyme activities in rice varieties with different phosphorus efficiency under phosphorus stress

Using six rice varieties with different phosphorus (P) use efficiency as the materials, the photosynthesis and active-oxygen-scavenging enzyme activities of the rice varieties under different P conditions were studied. Under deficient P condition, the photosynthetic rate (Pn) and soluble protein content (pro) were all gradually decreased with the growth process in the six tested varieties. The Pn and pro were always lower under deficient P condition than those under sufficient P condition. The Pn (ranging from 10.06-10.83 micromol CO2 x m(-2) x s(-1)), chlorophyll content (ranging from 3.32-3.56 mg x g(-1) FM) and pro (ranging from 33.08-33.95 mg x g(-1) FM) were all the highest in varieties with high-P efficiency, then in varieties with mid-P efficiency, and the lowest in varieties with low-P efficiency. There were no obvious differences on stomatal conductance (Gs) among the varieties. Meanwhile, the superoxide dismutase (SOD) activities of the tested varieties were all decreased with the process of deficient P stress. The SOD activities were also shown to be the highest in the varieties with high-P efficiency, then in the varieties with mid-P efficiency, and the lowest in the varieties with low-P efficiency under deficient P conditions. The malondialdehyde (MDA) contents in the tested varieties showed a reverse pattern of the SOD activities, with the highest in varieties with low-P efficiency and lowest in varieties with high-P efficiency. There was not an obvious change pattern on POD activity among the tested varieties under different P conditions. Under deficient P condition, the higher SOD activity and lower peroxidation degree of cell membrane system play important roles in improving the photosynthesis of the varieties with high-P efficiency.