芽期低温胁迫对早籼稻生长特性及产量的影响

Effects of low temperature stress at bud stage on growth characteristics and yield of early indica rice

【目的】研究芽期低温胁迫对早籼稻生长特性、生理特性及产量形成的影响,为其高产和稳产提供理论依据。【方法】以耐冷性品种陵两优7108和湘早籼6号,冷敏感品种株两优819和中嘉早17为试验材料,以自然条件下育秧为对照(CK),于芽期(芽长5 mm)进行低温(8℃)处理,处理10 d后将幼苗移至秧田恢复正常生长环境,移栽前1 d测定各处理不同品种的秧苗素质相关指标,并进行成熟期产量与产量构成因素分析。【结果】早籼稻在芽期遭受低温冷害导致各品种出苗率显著降低(P<0.05,下同),秧苗素质各指标不同程度下降,其中耐冷品种下降程度较小。低温胁迫处理下不同品种幼苗叶片的超氧化物歧化酶(SOD)及过氧化物酶(POD)活性均显著升高,可溶性蛋白含量及丙二醛(MDA)含量均显著增加,其中耐冷品种具有更强的保护性酶活性。与CK相比,芽期低温胁迫处理恢复生长后,不同品种的生育期延长,穗长和着粒密度降低,且耐冷品种降低幅度小于冷敏感品种。与CK相比,各品种芽期低温胁迫后的产量均降低,其中冷敏感品种株两优819和中嘉早17分别下降27.41%和20.90%,耐冷品种湘早籼6号和陵两优7108分别下降17.74%和12.82%。有效穗数和结实率下降是导致冷敏感品种减产的主要原因。【结论】芽期低温胁迫可降低早稻出苗率及秧苗素质,使植株生长受损,生育期延长,产量下降。综合生长特性和产量表现,耐冷品种陵两优7108和湘早籼6号受芽期低温影响较小,可作为耐低温双季直播早稻的推荐品种。

【Objective】To study the effects of low temperature stress at the bud stage on the growth characteristics,physiological characteristics and yield formation of early indica rice,to provide a theoretical basis for its high and stable yield.【Method】The cold-tolerant varieties Lingliangyou 7108 and Xiangzaoxian 6,and the cold-sensitive varieties Zhuliangyou 819 and Zhongjiazao 17 were used as test materials.Seedlings raised under natural conditions were used as the control(CK).At the bud stage(bud length reached 5 mm)for low temperature(8℃)treatment,after 10 d of treatment,the seedlings were transferred to the seedling field to return to normal condition.1 d before transplanting,the quality related indexes of seedlings of different varieties of each treatment were measured,and the yield and yield composition factors analysis at maturity period was conducted.【Result】The low temperature damage of early indica rice at bud stage significantly reduced the emergence rate of each variety under low temperature stress(P<0.05,the same below),and the quality related indexes of seedlings decreased to varying degrees.Among them,the degree of cold-tolerant varieties decreased to a small extent.Under low temperature stress,the superoxide dismutase(SOD)and peroxidase(POD)activities in seedling leaves of different varieties were significantly increased,and the soluble protein content and malondialdehyde(MDA)content were significantly increased.Among them,the cold-tolerant varieties had stronger protective enzyme activity.Compared with the CK,the growth period of different varieties was prolonged after low temperature stress treatment at bud stage,the ear length and grain density were reduced,and the reduction of cold-tolerant varieties was less than that of cold-sensitive varieties.Compared with CK,the yields of all varieties after low temperature stress at the bud stage decreased.Among them,the cold-sensitive varieties Zhuliangyou 819 and Zhongjiazao 17 decreased by 27.41%and 20.90%,respectively.The cold-tolerant varieties Xiangzaoxian 6 and Lingliangyou 7108 decreased by 17.74%and 12.82%respectively.The decrease of effective panicle number and filled grain percentagewere the main reasons for the decrease of coldsensitive varieties.【Conclusion】Low temperature stress at bud stage can reduce the emergence rate and seedling quality of early rice,damage the plant growth,prolong the growth period and decrease the yield.According to growth characteristics and yield performance,cold-tolerant varieties Lingliangyou 7108 and Xiangzaoxian 6 are less affected by the low temperature at budding stage,and can be recommended as low-temperature-tolerant double-season direct-seeded early rice varieties.