抽穗-灌浆期低温与弱光对超级稻结实率和生理性状的影响

Effects of low temperature and weak light during heading and grain filling on the seed-setting rate and physiological traits of super rice

以超级稻两优培九（两系杂交籼稻）、淮稻9号（粳稻）及高产品种汕优63（三系杂交籼稻）、扬辐粳8号（粳稻）为试材,通过盆栽种植试验,于抽穗至抽穗后10 d、抽穗后11~20 d分别进行低温和遮光处理,观察抽穗-灌浆期不同阶段低温、弱光胁迫对超级稻结实率和部分生理性状的影响。结果表明：低温或弱光胁迫显著降低4个水稻品种的结实率、剑叶光合速率、过氧化氢酶活性、超氧化物歧化酶活性、根干重、根系氧化活力和根系玉米素＋玉米素核苷含量,增加剑叶丙二醛含量和过氧化物酶活性。低温与弱光对2个超级稻品种产量和生理性状的影响高于对照,20℃低温处理高于40%遮光处理,抽穗-抽穗后10 d时段高于抽穗后11~20 d时段。结果提示超级稻品种对温度和光照的反应较常规高产品种更为敏感,保证结实期特别是开花灌浆早期温光条件对超级稻灌浆尤为重要。

Two super rice cultivars,Liangyoupeijiu and Huaidao 9 and two high-yielding and elite check cultivars,Shanyou 63 and Yangfujing 8,were grown in pots.A low temperature treatment at 20℃and a weak light treatment with the shading off 40%light（light transmission rate of 60%）were conducted 0-10 days and 11-20 days after heading,respectively.The natural temperature and light were taken as the control.The seed-setting and some physiological traits were investigated.The results showed that the low temperature and weak light stress significantly decreased grain yield,the seed-setting rate,net photosynthetic rate,activities of catalase and superoxide dismutase of the flag leaf,root dry weight,root oxidation activity,and zeatin＋zeatin riboside content in roots,whereas they markedly increased malondialdehyde content and peroxidase activity in the flag leaf.The effect of low temperatue or weak light on grain filling was greater for the super rice varities than for the check varieties,greater under the low temperature at 20 ℃ than under the weak light with shading off 40%light,and greater at 0-10 days after heading than at 11 —20 days after heading.The results suggest that the response to temperature and light is more sensitive in super rice than in nomal rice varieties,and it is more important for super rice to have good conditions of temperature and light during grain filling especially at heading and early grain filling stages.