盐胁迫对2个不同盐敏感性水稻品种（系）叶片光合特性与产量的影响

研究盐胁迫对不同盐敏感性水稻品种（系）叶片光合作用、叶绿素荧光参数及产量的影响,为耐盐品种选育和盐碱地有效开发利用提供理论参考。以武运粳30（盐敏感性品种）和振稻23309（耐盐性品系）为材料,比较研究不同盐分梯度（0%、0.07%、0.14%、0.21%、0.28%、0.35%）对水稻产量和抽穗期水稻叶片光合特性的影响。结果表明,随盐浓度的提高,两个品种（系）产量呈现递减趋势,且武运粳30的降幅更大。在盐胁迫条件下,武运粳30的穗数、穗粒数、结实率显著降低且降幅显著大于振稻23309,两个品种（系）千粒重变化都不明显。与对照相比,在低盐胁迫（0.07%）下,振稻23309的叶片净光合速率（P_n）、叶绿素含量（SPAD值）、水分利用效率（WUE）、表观叶肉导度（AMC）、荧光参数（潜在活性F_v/F_o、最大光化学效率F_v/F_m、实际光化学效率Φ_PSⅡ、光化学猝灭系数q_p、非光化学猝灭系数q_N）均显著上升;0.14%盐浓度处理下,两个基因型水稻除q_N显著提高外,其余各参数均呈下降趋势,且振稻23309的降幅要小于武运粳30;盐浓度大于0.14%时,两个基因型水稻各参数均显著降低,且武运粳30的降幅更大。由此可见,盐胁迫对水稻产量和叶片光合特性的影响不仅与盐浓度有关,且存在显著的基因型差异;水稻叶片叶绿素含量高、光合作用的气孔限制向非气孔限制转变慢、植株水分利用率高、光合系统Ⅱ非辐射能耗散增加、光保护能力强等因素是耐盐品系振稻23309表现出较强耐盐性的内在原因。

Effects of Saline Stress on Leaf Photosynthesis Characteristics and Grain Yield of Two Rice Cultivars(Lines)

This study was aimed at investigating the effects of saline stress on photosynthesis, chlorophyll fluorescence, and yield. Our study could provide useful information for breeding salt-tolerant varieties as well as effective development and utilization of saline-alkali land. An experiment was conducted on two rice cultivars (lines) Wuyunjing 30 (saline sensitive) and Zhendao 23309 (saline tolerant) to study the effects of different saline stress (0%, 0.07%, 0.14%, 0.21%, 0.28%, 0.35%) on grain yield, photosynthetic parameters, and chlorophyll fluorescence variation at heading stage. The results showed that the yield of both cultivars (lines) was reduced gradually with the increase of salt content, while the yield of Wuyunjing 30 was decreased more compared to Zhendao 23309, while there was no significant difference in 1000-grain weight between salt treatments. Under low salt concentration stress (0.07%), net photosynthetic rate (P_n), SPAD, water use efficiency (WUE), apparent mesophyll conductance (AMC), F_v/F_o, F_v/F_m, Φ_PSⅡ, q_p and q_N were increased significantly compared with the control. When the salt concentration was 0.14%, all parameters of Zhendao 23309 were increased except q_N, showing salt resistance of Zhendao 23309. Both genotypes showed significant decrease in photosynthesis when the salt concentration was higher than 0.14%. Therefore, the effects of saline stress on photosynthetic characteristics and yield of rice was not only related to salt concentration, but also to genotype. Higher chlorophyll content in rice leaves, slower transition from stomatal to non-stomatal restriction, higher moisture utilization rate, greater heat dissipation of PSⅡ and photoprotection capacity are the characterisics responsible for strong salt tolerance.