淹涝胁迫对寒地水稻生长和产量的影响研究

2018年在黑龙江省庆安县选用寒地水稻龙粳31品种进行淹水试验，在拔节孕穗期、抽穗开花期，分别设定3个淹水深度（1/3株高、2/3株高、3/3株高）、2个淹水历时（3 d、7 d）共12个淹水处理，测定淹水前后的株高、叶面积、干物质及收获后的每穗粒数、结实率、千粒重及产量等。结果表明：水稻淹水后，株高、叶面积指数、干物质平均增长量基本高于同时期对照组，在一定程度上可以说明适度的淹涝胁迫对水稻植株生长具有促进作用，拔节孕穗期各项与对照组相比的增长程度均低于抽穗开花期；不同淹涝胁迫均导致水稻减产，拔节孕穗期全淹没7 d减产最严重，穗结实粒数仅55粒，千粒重16.9 g，远低于对照，减产率高达70%，抽穗开花期全淹没7 d减产也较严重，穗结实粒数为71粒，千粒重略低，但单位面积有效穗数最少，为2.83×106穗，减产率达57%；淹水深度1/3 h、2/3 h、3/3 h处理的平均减产率依次为16%、18%、48%，淹水持续3 d、7 d的平均减产率分别为21%、33%，可见随着淹水深度加深、淹水历时加长，水稻减产幅度加大；淹涝胁迫条件下，拔节孕穗期水稻产量的下降幅度大于抽穗开花期，导致两个发育期减产的主要产量构成因素分别为穗结实粒数、单位面积有效穗数。

Impact of waterlogging stress on japonica rice growth and yield in cold region

In 2018, Longjing-31 of Japonica rice variety was planted in Qing''an County of Heilongjiang Province for the rice flooding experiment in cold region. At the jointing and booting stage, heading and flowering stage, three flooding depths (1/3 plant height, 2/3 plant height, and total plant height) and two flooding durations (3 d and 7 d) are designed for 12 flooding treatments, respectively. During the experiment, the tiller number before and after flooding, the plant height, LAI (leaf area index), dry matter, grain number per panicle, seed setting rate, 1 000-grain weight, and yield are measured and comparative analysis is conducted. The results are shown below. 1) After flooding, the average increase of plant height, LAI, and dry matter is higher than that of the CK (control check), which indicates that the moderate waterlogging stress could promote the growth of rice plant to some extent. Compared with the CK, the growth degree of all items in jointing and booting stage is lower than that in heading and flowering stage. 2) Different waterlogging stress leads to the reduction of Japonica rice yield. The yield is reduced most seriously after 7 d of total submergence at the jointing and booting stage, the number of grains per ear is only 55, and the 1 000-grain weight is 16.9 g, which are far lower than those of the CK, so the yield reduction rate is as high as 70%. The yield is reduced seriously after 7 d of total submergence at heading and flowering stage, the number of grains per ear is 71, the 1 000-grain weight is slightly lower, but the number of effective ears per unit area is 2.83 × 106, which is the least in all treatments, so the yield reduction rate is 57%. The average yield reduction rates of three flooding depths(1/3 plant height, 2/3 plant height, and total plant height) are 16%, 18%, and 48%, respectively, and the average yield reduction rates of durative waterlogging for 3 d and 7 d are 21% and 33%, respectively. On the whole, the reduction of rice yield increases with the deepening and lengthening of waterlogging. 3) Under the flooding stress, the decrease of rice yield at jointing and booting stage is greater than that at heading and flowering stage, and the main yield components leading to yield reduction in the two growth stages are the number of grains per ear and the number of effective ears per unit area, respectively.