不同直播种植模式对水稻根系特征和产量形成的影响

Effects of Different Direct-sowing Planting Patterns on Characteristics of the Roots and Yield of Rice

为了明确不同直播种植模式下水稻(Oryza sativa L.)的产量形成机制,采用机械穴直播(XB)、机械条直播(TB)、人工撒播(SB)种植模式,以传统人工插秧(CY)为对照,考察了水稻根系特征、群体动态和光合作用产物转运等性状。结果表明,齐穗期XB和TB根重均比CY显著增加,其主根数、根总长、根尖数以及根表面积均有不同程度的提高。根系伤流量齐穗期仅XB高于CY,TB和SB均比CY显著下降,灌浆期3种直播模式均较CY显著下降。水稻叶面积指数有相似的变化规律。直播模式下水稻齐穗前光合作用产物积累量较大,其茎鞘物质输出率和转换率显著高于CY。与CY相比,XB产量提高5.8%,TB和SB分别降低4.2%和13.2%。XB和TB种植模式下,水稻千粒重增加,但每穗总粒数有所减少。总体来说,机械直播较人工撒播用种量减少、植株布局有序性提高,根系形态改善,地上部分光合作用产物积累明显提高。但是,相对人工插秧,其灌浆期根系活力明显下降。

Using manual transplanting as control （CY）,the field experiment was conducted with three direct-sowing patterns （mechanic hill-direct-seeding（XB）,mechanic drilling（TB） and manual broad-cast sowing（SB） to investigate root characteristics,population dynamics and photosynthetic material transportation of rice.The results showed that root weight per hill of rice for XB and TB was significantly increased at heading stage than that for CY.The main root number,total root length,root tips number and root surface area was increased to varying content.The rice root exudates for XB were larger than that for CY at heading stage.But the rice root exudates for TB and SB was significantly decreased.The exudates for the three direct-sowing patterns were lower than that for CY at filling stage.Similar variation was found at the leaf area index （LAI）.Photosynthetic biomass accumulation of rice at heading stage under the direct-sowing patterns was more than that of CY,so their EPMSS （export percentage of the matter in stem-sheath） and TPMSS （transformation percentage of the matter in stem-sheath） were higher than that of CY,significantly.Compared with CY,the yield of XB increased by 5.8％ but the yield of TB and SB reduced by 4.2％ and 13.2％.The 1 000-grain weight increased for XB and TB,but grain number per panicle decreased.With comparison of artificial broad-cast sowing pattern,the amount of seed reduced as the mechanic direct-sowing patterns were adopted.The plants layout was orderly improved and their root morphology and vitality was enhanced,and photosynthetic matter accumulation increased significantly.Compared with artificial planting,the root vitality reduced obviously.As a result,improving rice root vitality during the latter growth stage under direct-sowing patterns is an important way to increase potential of yield.