旱涝交替胁迫对水稻干物质生产分配及倒伏性状的影响

Effect of alternate flooding and drought stress on biomass production, distribution and lodging characteristic of rice

为揭示旱涝交替胁迫水稻干物质生产和分配规律,研究其对水稻倒伏相关形态性状、力学性状及化学成分的影响,于2013年5—10月在江苏省河海大学南方地区高效灌排与农业水土环境教育部重点实验室进行不同灌溉方法的粳稻盆栽试验。试验共设分蘖期涝-轻旱交替胁迫（T-LD）、分蘖期涝-重旱交替胁迫（T-HD）、拔节期涝-轻旱交替胁迫（J-LD）、拔节期涝-重旱交替胁迫（J-HD）和全生育期浅水勤灌（CK）5个处理。结果表明,在开花期以后,各灌溉处理的功能叶的叶绿素含量与水稻移栽后天数呈二次曲线关系,且决定系数R2均大于0.97（P〈0.01）;在开花期后,水稻剑叶的叶绿素含量和光合速率存在线性正相关（P〈0.001）。分蘖期旱涝交替胁迫处理（T-LD和T-HD）的剑叶面积、开花后平均叶绿素含量以及光合速率为CK处理的1.1~1.2倍,而茎鞘贮藏物质的平均输出率和转化率则分别为CK处理的32%和22%;拔节期旱涝交替胁迫处理（J-LD和J-HD）的剑叶面积、茎鞘贮藏物质的平均输出率和转化率分别为CK处理的84%、33%和37%,而开花后其平均光合速率为CK处理的1.19倍。与CK及分蘖期旱涝交替胁迫处理相比,拔节期旱涝交替胁迫处理显著提高基部以上第1伸长节间的抗折安全系数（P〈0.05）。研究可为通过灌溉方式实现水稻抗倒和高产的目标提供依据。

Lodging is one of the important constraints to high quality and stable production of rice.This study was conducted in the Key Laboratory of Efficient Irrigation-Drainage and Agricultural Soil Water Environment in Southern China,Ministry of Education,Nanjing,China from May to October in 2013 to investigate the response of alternate flooding and drought stress on biomass production and distribution in different organs of rice（Oryza sativa L.Nanjing 44） and their relationships with morphological and mechanical traits as well as chemical concentration relating to stem lodging characteristics under alternate drought and flooding stress during different growth stages.Five treatments,alternate stress of light drought-flooding-light drought in tillering stage（T-LD）,alternate stress of heavy drought-flooding-heavy drought in tillering stage（T-HD）,alternate stress of light drought-flooding-light drought in jointing stage（J-LD）,alternate stress heavy drought-flooding-heavy drought in jointing stage（J-HD） as well as irrigation with shallow water depth（0-5 cm） for all the stages except for yellow maturity（CK）,were set up.In this experiment,changes of chlorophyll contents and photosynthesis rates of flag leaves after the flowering stage as well as the percentage of dry-matter exportation from stem-sheath（PDESS） and the percentage of the dry-matter transformation from the stem-sheath part to the grain part（PDTSS） were investigated.In additon,the stem morphological and mechanical traits as well as chemical concentrations and their relationships with stem lodging characteristic were studied.The results showed that there were significant quadratic curve relationships between chlorophyll contents and days after transplanting（P〈0.01）.In addition,there were significant positive linear relationships between chlorophyll contents and photosynthesis rate of flag leaves after the flowering stage（P〈0.001）.Compared with the CK,T-LD and T-HD treatments significantly increased the leaf areas,chlorophyll contents and photosynthesis rates of flag leaves after the flowering stage,but significantly decreased the PDESS and the PDTSS; the leaf areas,chlorophyll contents and photosynthesis rates of flag leaves after the flowering stage of alternate stress of drought-flooding-drought in the tillering stage were about 1.1-1.2 times as those of CK,respectively; the PDESS and PDTSS were 32% and 22% of those of CK,respectively.Compared with the CK,J-LD and J-HD treatments significantly increased the chlorophyll contents and photosynthesis rates of flag leaves after the flowering stage but did not significantly increase the leaf areas,the PDESS and the PDTSS.The leaf areas of flag leaves,the PDESS and the PDTSS of alternate stress of drought-flooding- drought in the jointing stage were 84%,33% and 37% of those of CK,respectively; the photosynthesis rates of flag leaves after the flowering stage were 1.19 times as those of CK,respectively.Compared with the CK,J-LD and J-HD treatments significantly increased the safety factor against stem breakage,which might be related to the improved dry-matter translocation amount and translocation efficiency from stem-sheath to grain part of rice plants as well as the increased gravity centre height and the ratio of gravity centre caused by the improved translocation amount of carbohydrate generated in flag leaves to the grains.There were significant negative relationships between harvest index and safety factor.This study could provide valuable information for keeping high grain yield as well as improving lodging resistance of rice plant by irrigaiton methods.