籼、粳超级稻品种根系形态及若干生理特征的差异

为阐明籼、粳超级稻根系干物质积累与分布特征和主要形态生理性状指标的差异及其与产量形成的关系,以当地主体且具有代表性的2个超级杂交籼稻组合和2个常规粳型超级稻品种为试验材料,对麦稻两熟制条件下籼、粳超级稻单茎和群体根干重、总根长、根数、根体积、根系吸收面积、发根力、抽穗后根系伤流强度及根冠比、每条根长、根直径、根密度、颖花根流量、抽穗期根系在土层中的分布和产量构成等方面进行了系统的比较研究。结果表明:(1)整个生育期,粳稻的根冠比、每条根长、发根数、发根体积、发根干重及颖花根流量、穗数、群体颖花量、结实率和实收产量均高于籼稻,而根直径、每穗粒数和千粒重低于籼稻,其中根冠比、每条根长、颖花根流量、穗数、每穗粒数、结实率和实收产量差异达显著或极显著水平;(2)粳稻抽穗前(含抽穗期)单茎根干重、总根长、根数、根体积和根系总吸收表面积及根密度均低于籼稻,但差异不显著,而成熟期这6个指标粳稻均显著或极显著高于籼稻;(3)粳稻拔节前单茎活跃吸收表面积和活跃吸收表面积比均小于籼稻,而拔节后(含拔节期)两者差异趋势与之相反,差异显著或极显著;(4)除拔节期群体根干重、拔节期和抽穗期群体根数外,其他群体形态生理特征指标粳稻均显著或极显著高于籼稻;(5)无论是单茎还是群体,粳稻抽穗后0~35 d根系伤流量均显著或极显著高于籼稻;(6)粳稻0~10 cm土层根系干重所占比例极显著低于籼稻,10 cm以下土层根系干重占根系总干重的比例极显著高于籼稻,粳稻扎根更深,进一步强化了植株抗倒防早衰能力。与超级杂交籼稻相比,常规粳型超级稻抽穗后根系生长优势不断加大,特别是群体生长优势,成熟期粳稻所有根系形态生理特征指标均优于籼稻,是粳稻高产形成的重要原因和保障。

Difference of Root Morphological and Several Physiological Characteristics between Indica and Japonica Super Rice Varieties

The objective of this study was to reveal the difference of dry matter accumulation and its distribution, and the main morphological and physiological characteristics in roots between indica and japonica super rice, and their relationship with yield formation. A field experiment was conducted using two main representative super hybrid indica combinations and two conventional japonica super rice varieties in wheat-rice double cropping regions. Dry weight of root, total root length, root number, root volume, root absorbing area, root germination ability and root bleeding intensity after heading for both single stem and population, root-shoot ratio, single root length, root diameter, root density, root bleeding per spikelet, root distribution in the soil at heading and yield components were analyzed systematically. Results showed as follows: (1) For the whole growth duration, root-shoot ratio, single root length, root germinating number, root germinating volume, root germinating dry weight, root bleeding per spikelet, number of panicles, total spikelets, seed-setting rate and grain yield of japonica rice were higher thanthose of indica rice, while root diameter, spikelets per panicle and 1000-grain weight followed an opposite tendency, with root-shoot ratio, single root length, root bleeding per spikelet, number of panicles, spikelets per panicle, seed-setting rate and grain yield being a significantly different. (2) Before heading, dry weight of root, total root length, root number, root volume and total absorbing surface area of root per stem and root density of japonica rice were lower than those of indica rice, though not significantly, and higher than those of indica rice significantly at maturity. (3) Before jointing, active absorbing surface area per stem and ratio of active absorbing surface area to total absorbing surface area in japonica rice were less than those in indica rice significantly, which showed an opposite trend after jointing. (4) Population indicators of morphological and physiological characteristics of japonica rice except for population root dry weight at jointing and root number of population at jointing and heading were higher than those of indica rice significantly. (5) Root bleeding intensity during 0–35 d after heading was higher in japonica rice than in indica rice significantly whether it was based on a single stem or population. (6) Ratio of root dry weight in the 0–10 cm layer to total root dry weight was lower in japonica rice than in indica rice significantly, with an opposite trend for the >10 cm layer, which indicated the deep-rooted characteristic of japonica rice can strengthen its resistance to lodging and premature senescence. Compared with super hybrid indica rice, root growth advantages of conventional japonica super rice after heading were increased, especially for population growth advantages, and all the root morphological and physiological characteristics indicators of japonica rice at maturity were better than those of indica rice, which is the important cause and assurance for high-yielding formation of japonica rice.