摘要
较系统地研究了抽穗期超高产杂交稻‘华安 3号’(‘X0 75’ב紫恢 10 0’)冠层顶部 5片叶片的光合功能。结果表明 ,‘华安 3号’剑叶的光系统Ⅱ (PSⅡ )光化学最大效率 (Fv/Fm)、开放的PSⅡ反应中心捕获激发能效率(Fv′/Fm′)、PSⅡ电子传递量子效率 (ΦPSⅡ)、光化学猝灭系数 (qP)、表观电子传递效率 (ETR)、光合色素尤其是叶绿素 (Chl)和类胡萝卜素 (Car)中的新黄素、黄体素和 β_胡萝卜素 (β_Car)的含量等均优于其下的各叶 ,而PSⅡ的激发压力 (1_qP)低于其它叶片。经对叶片低温 (77K)荧光发射光谱的Gaussian解析 ,与其它各叶片相比 ,剑叶PSⅡ核心天线复合物CP4 7和光系统Ⅰ (PSⅠ )的含量较高 ,而非活性的PSⅡ捕光色素蛋白复合体 (LHCⅡ )聚集态含量较少。研究证明 :1)水稻在决定籽粒产量的生育后期 ,其干物质的积累主要是由冠层最上面的 3片叶的光合作用所提供 ;2 )在叶片衰老过程中 ,光合反应中心的衰老早于天线系统 ;3)杂交稻的光保护途径之一 ,可能在于光抑制条件下通过增加PSⅠ含量及其对光能的吸收并刺激环式电子传递高速运转 ,从而对光合器起保护作用 ;4 )水稻叶片在衰老过程中 ,可能通过部分Chlb还原为Chla ,以降低LHCⅡ的含量 ,从而减少对光能的捕获 。
In order to improve rice yields to feed a growing population, China has carried out a `Super High-Yield Rice Project' since 1996. Tremendous progress was made during the `Ninth Five-Year Plan' and several new varieties of rice hybrids were released. `Hua-an 3' (`X07S'×`Zihui100') is a new high yield variety that has yields of more than 10 500 kg·hm -2; this compares with yields of 7 500-8 500 kg·hm -2 in the traditional hybrid rice `Shanyou 63' (`Zhenshan 97A'×`Minghui 63'). The photosynthetic functions and pigments of the upper most 5 senescing leaves of the canopy of `Hua-an 3' were studied by techniques of fluorescence induction kinetics, low temperature (77K) fluorescence emission spectrum and HPLC. The results showed that the maximal quantum yield of PSⅡ photochemistry (F v/F m), efficiency of excitation energy captured by open PSⅡ reaction centers (F v′/F m′), quantum yield of PSⅡ electron transport (Φ PSⅡ), photochemical quenching coefficient (qP), and the content of photosynthetic pigments, especially chlorophyll (Chl), neoxanthin (N), lutein (L) and β-carotene (β-Car), of the flag leaf were higher than those of other leaves but its excitation pressure (1-qP) was lower. It was shown that the content of the core antenna complex CP47 in photosystemⅡ (PSⅡ) and photosystem Ⅰ (PS Ⅰ) of the flag leaf also was higher than in other leaves, but the content of its non-active aggregate of light harvesting complex in PSⅡ (LHCⅡ) derived from the Gaussian analysis of low-temperature (77K) fluorescence emission spectra was lower than that of the other leaves. Our research results are as follows: 1) at later growth and development stages of rice, the dry matter of grain was mainly provided by most photosynthesis occurred in the uppermost 3 leaves in the canopy; 2) in the course of leaf senescence, the senescence of photosynthetic reaction centers was quicker than that of the antenna system; 3) one of the photoprotective pathways in hybrid rice may be through an increase in the content of PS Ⅰ, absorption of more light energy, and stimulating a high speed electron transport cycle in order to protect the photosynthetic apparatus under photoinhibitory conditions; 4) in the course of leaf senescence of rice, partial chlorophyll b was probably reduced to chlorophyll a, to decrease the content of LHCⅡ, thus reducing the amount of energy absorbed by LHCⅡ and decreasing the amount of photoinhibitory damage.
出处
《植物生态学报》
CAS
CSCD
北大核心
2004年第1期39-46,共8页
Chinese Journal of Plant Ecology
基金
国家重点基础研究发展规划项目 (G19980 10 10 0 )
中国科学院百人计划项目
关键词
杂交稻
衰老
冠层叶片
光化学活性
低温荧光
光合色素
华安3号
Superhigh-yield rice, Senescing leaves, Photochemical activity, Low temperature (77K) fluorescence emission spectrum, Photosynthetic pigments