超高产杂交稻在强光胁迫及其恢复进程中的PSⅡ活性和叶黄素循环(英文)

PSⅡ Photochemistry and Xanthophyll Cycle in Two Superhigh-yield Rice Hybrids, Liangyoupeijiu and Hua-an 3 During Photoinhibition and Subsequent Restoration

研究了两系超高产杂交稻 (OryzasativaL .)“两优培九”和“华安 3号”以及多年来大面积推广的三系杂交稻“汕优 6 3”剑叶的PSⅡ活性和叶黄素循环对强光胁迫及其恢复进程的响应。结果表明 ,在 2 0 0 0 μmolphotons·m-2 ·s-1的强光胁迫下 ,3个杂交稻的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′)和PSⅡ的实际光化学转能效率 (ΦPSⅡ)都随着光抑制进程而下降 ,其中以“汕优 6 3”下降的幅度最大。光抑制过程中 ,杂交稻叶黄素循环的紫黄素 (V)组分迅速下降 ,与此同时 ,脱环氧化组分环氧玉米黄素 (A)和玉米黄素 (Z)迅速积累 ,而超高产杂交稻“两优培九”和“华安 3号”的A和Z的积累速度大大高于“汕优 6 3”。伴随A和Z的快速积累 ,它们的叶黄素循环的脱环氧化状态 (DES)迅速上升 ,并在半小时左右基本达到最大值 ,其中“两优培九”和“华安3号”DES的上升速率仍然较“汕优 6 3”高。光抑制处理结束后 ,转移到弱光 (70 μmolphotons·m-2 ·s-1)条件下恢复过程中 ,两个超高产杂交稻的Fv/Fm、Fv′/Fm′和ΦPSⅡ 的恢复速率和恢复水平都高于“汕优 6 3”。同时 ,它们的叶黄素循环组分V、A、Z以及DES都逐渐恢复 ,但“两优培九”和“华安 3号”

PSⅡ photochemistry and xanthophyll cycle during photoinhibition (exposed to strong light of 2 000 μmol photons·m -2 ·s -1 ) and the subsequent restoration were compared between two superhigh_yield rice hybrids (Liangyoupeijiu and Hua_an 3, the newly developed rice hybrids from two parental lines) and the traditional rice hybrid Shanyou 63 developed from three parental lines. The results showed that the maximal efficiency of PSⅡ photochemistry ( Fv/Fm ), the efficiency of excitation energy capture by open PSⅡ centers ( Fv′/Fm′ ), and the yield of PSⅡ electron transport ( Φ PSⅡ ) of the three rice hybrids decreased during photoinhibition. However, a greater decrease in Fv/Fm , Fv′/Fm′ , and Φ PSⅡ was observed in Shanyou 63 than in Liangyoupeijiu and Hua_an 3. At the same time, the components of xanthophyll cycle, antherxanthin (A) and zeathanxin (Z) increased rapidly while violaxanthin (V) decreased considerably. Both the rate of accumulation and the amount of A and Z in the two superhigh_yield rice hybrids were higher than that in Shanyou 63. The de_epoxidation state (DES) of xanthophyll cycle increased rapidly with the fast accumulation of A and Z, and reached the maximal level after first 30 min during photoinhibition. Of the three hybrids, the increasing rate of DES in Liangyoupeijiu and Hua_an 3 was higher than that in Shanyou 63. After photoinhibition treatment, the plant materials were transferred to a dim light (70 μmol photons·m -2 ·s -1 ) for restoration. During restoration, both chlorophyll fluorescence parameters and xanthophyll cycle relaxed gradually, but the rate and level of restoration in the two superhigh_yield rice hybrids were higher than those in Shanyou 63. Our results suggest that Liangyoupeijiu and Hua_an 3 had higher resistance to photoinhibition and higher capacity of non_radiative energy dissipation associated with xanthophyll cycle, as well as higher rate of restoration after photoinhibition, than Shanyou 63 when subjected to strong light.