普通野生稻和栽培稻光合功能衰退的比较

Comparison on Some Aspects of Photosynthetic Declination of Wild Rice and Cultivated Rices

以普通野生稻 ( Oryza sativa L.f.spontanea Roschev.)和五种栽培稻包括粳稻品种 9516( O.sativa L var. 9516)、武育粳 3号 ( Wuyujing3)、 97- 7,籼稻品种 NAU30 3和杂交籼稻汕优 63为材料系统地比较了野生稻与栽培稻之间、栽培稻不同品种之间光合功能衰退进程的差异并对造成这些差异的生理生化机理进行初步研究。结果表明 ,在自然演变和人工选择的作用下光合参数都向着有利于提高光合功能的方向发展 :从野生稻到籼稻再到粳稻叶绿素含量逐渐升高 ,其含量相对稳定期也逐渐增长 ;净光合速率逐渐提高 ,光合速率高值期也逐渐变长 ;单位叶面积叶源量逐渐增大。光合作用关键酶 Rubisco的羧化酶活性仅有极小的区别 ;内肽酶在光合速率高值期活力很低 ,在光合速率高值期的终点附近开始升高并在光合功能衰退的后期达到很高的水平 ,但不同的类型开始的早晚不同。这说明衰退的早期内肽酶的作用不大 。

Wild rice ( O.sativa L. f. spontanea Roschev.) and 5 cultivated rices including 9516( sinica type cv.), Wuyujing3 ( sinica type cv.), 97-7 ( sinica type cv.), NAU303 ( indica type cv.), Shanyou63 ( ind[KG-4]ica type hybrid) were used to study systematically differences of photosynthetic declination between them and mechanisms for differences. The relevant results indicated that photosynthetic parameters tended to become more advantageous to photosynthetic function promotion: From wild rice to indica rices and from ind[KG-4]ica rices to sinica rices, chlorophyll content became higher and higher, and RSP (relative steady phase) of chlorophyll content longer and longer; net photosynthetic rate got higer and higher, and their APD (active photosynthetic duration) longer and longer too; the LSC (leaf source capacity) per leaf area exhibited bigger and bigger. Soluble protein content in cultivated rice flag leaves was higher than those in wild rice leaves. There was a little difference in specific activities of RuBP carboxylase between wild and cultivated rice flag leaves. The activity of endopeptidase kept in low level in early phase of photosynthetic declination, and began to rise near the end of APD and reached very high level in the latest phase, but started to rise in different times for different types of rices. It indicates that endopeptidase mainly plays a role during late (irreversible) phase of declination.