亚洲一区欧美在线,日韩欧美视频免费观看,色戒的三场床戏分别是在几段,欧美日韩国产在线人成

In order to explore the influence of different irrigation methods on growth and physiological characteristics of dry direct seeding rice in the black soil region of Northeast China, according to different irrigation methods, three test treatments were set: drip irrigation dry direct seeding (DH), flood irrigation dry direct seeding (MH) and basin irrigation dry direct seeding (HS), with conventional basin irrigation (CK) as control. The dynamic changes of dry matter accumulation process and photosynthetic characteristics of rice at different growth stages were quantitatively analyzed by fitting curves. Results showed that dry matter accumulation of rice under different treatments presented a slow-fast-slow S-curve change rule along with growth time, but dry matter accumulation, start-stop time of rapid growth, growth rate and growth period varied with irrigation methods. The dry matter accumulation of rice in descending order was HS, MH, DH and CK. The rapid growth period of rice treated with CK started in the middle tillering stage, and the rapid growth period of rice in other treatments started at the transitional stage from the middle tillering stage to the end tillering stage. The rapid dry matter growth period of the different treatments all ended in the milk maturity stage. After heading and flowering period, chlorophyll SPAD value in dry direct seeding treatment was decreased faster than that in CK; except late tillering stage, net photosynthetic rate (Pn), transpiration rate (Tr) and stomatal conductance (Gs) in dry direct seeding treatment were lower than that in CK, and stomatal limit value (Ls) was higher than that in CK. The correlation analysis showed that the dry matter accumulation of dry direct seeding rice was positively correlated with chlorophyll SPAD value, Pn, Tr and Gs（P<0.01）. The analysis of photosynthetic characteristics parameters and dry matter accumulation showed that dry direct seeding DH, MH and HS had lower photosynthetic characteristics than that in CK, while dry matter accumulation was better than that in CK; HS had better photosynthetic characteristics and dry matter accumulation than DH and MH. The research results can provide theoretical basis for selecting rice planting mode in black soil region of Northeast China.