摘要
研究了一个在田间发现的水稻叶绿素b含量低的突变体叶片的光合功能衰退。和野生型相比 ,突变体的光合功能在叶片一生中较稳定 ;超氧阴离子和H2 O2 含量低 ,但活性氧清除系统的SOD和CAT酶活性差异不显著。由于突变体叶片中还原态辅酶Ⅱ和氧化态辅酶Ⅱ的比值低于野生型 ,因而认为其光合电子传递速率和羧化反应消耗电子速率之间比野生型更加平衡 ,是其光合功能较野生型稳定的原因。
A rice mutant that had a lower chlorophyll b content found in fields was studied in this paper. As compared with wild type, the photosynthetic functions of the mutant were more stable in throughout the life span of its leaves (Fig.1). The O -· 2 and H 2O 2 contents in mutant leaves were lower than those in the wild type throughout their life span (Fig.2). Along with leaf senescence, both SOD and CAT contents increased rapidly, especially at the end of leaf life span. SOD and CAT can scavenge O -· 2 and H 2O 2 in leaf. But no apparently difference in activities of either enzyme between two types of rice was found (Fig.3). So the difference in O -· 2 and H 2O 2 contents must be due to the higher active oxygen production. Chlorophyll fluorescence and carbon assimilation analysis showed that there was a better balance between the rate of electron transfer driven by light reaction (J f) and the rate of electron utilization by carbon assimilation reaction (J c) in mutant throughout the life span of a leaf (Fig.4). The NADPH/NADP + ratio in the mutant was also lower than that in wild type (Fig.5). It was concluded that the better balance between the electron flow rate in light reaction and electron utilized rate through carbon assimilation in the mutant might be the reason that its photosynthetic apparatus is more stable during the leaf life span. The better balance means the less active oxygen produced in chloroplast.
出处
《植物生理与分子生物学学报》
CAS
CSCD
2003年第2期104-108,共5页
Journal Of Plant Physiology and Molecular Biology
基金
国家重点基础研究发展规划项目 (No .G19980 10 10 0 )资助
关键词
叶绿素B
突变体
水稻
衰老
活性氧
chlorophyll b
mutant
rice
senescence
active oxygen
