耕作方式对稻茬小麦幼苗茎蘖生长生理和生产力的影响

Effects of Tillage Methods on Growth and Physiology of Seedlings Stem and Tillers and Their Productivity of Wheat in Rice Stubble

为探究稻茬小麦壮苗培育和高产栽培途径,在水稻秸秆全量还田条件下研究了耕翻(PR)、旋耕(RR)和免耕(NT)3种耕作方式对冬前麦苗主茎和分蘖生长生理和成熟期单穗产量的影响。结果表明,耕翻方式下越冬始期茎蘖数分别比旋耕和免耕方式下高1.5%,12.8%,差异显著(P<0.05);单株叶面积和干质量分别达到94 cm^(2)和787 mg,均显著高于免耕(P<0.05)。相比免耕,耕翻显著提升了小麦苗期主茎、第一、第二和第三分蘖顶部全展叶片的硝酸还原酶(NR)、谷氨酰胺合成酶(GS)、谷氨酸合成酶(GOGAT)活性,明显促进了二磷酸核酮糖羧化酶(Rubisco)、丙酮酸磷酸双激酶(PPDK)、磷酸丙糖异构酶(TPI)活性和叶绿素相对含量(SPAD值),并促进了蔗糖合成酶(SS-Ⅱ)、蔗糖磷酸合成酶(SPS)活性和叶片可溶性糖含量的提高(P<0.05);并且显著提高了主茎、第二和第三分蘖的叶片氮含量(P<0.05)。此外,耕翻和旋耕方式还增加了主茎、第一和第二分蘖的叶面积和干质量。表明耕翻较旋耕和免耕方式更有利于协同提升苗期主茎和低位分蘖的氮代谢、糖代谢和光能利用水平,进而增加光合生产能力,形成壮苗。而旋耕对碳氮代谢和光合能力的提升高于免耕,但弱于耕翻。耕翻下主茎穗的穗粒数、单粒质量和旋耕差异不显著,但二者均显著高于免耕(P<0.05)。耕翻下第一和第二分蘖的穗粒数显著高于旋耕和免耕(P<0.05),但耕翻与旋耕间第一、二和三分蘖穗的单粒质量和单穗质量差异不显著(P>0.05)。由此可见,通过耕翻方式可提升稻茬小麦冬前幼苗的主茎、第一、二分蘖的糖氮代谢和光合生理活性,形成壮苗个体,促进了单穗生产力尤其是穗粒数的增加。

To investigate the cultivation approach achieving robust seedlings and high yields of wheat in rice stubble,the effects of three tillage methods,including plow tillage followed by rotary tillage(PR),rotary tillage twice(RR),and no-tillage(NT),on the growth and physiology of main stem and tillers of wheat seedlings and their single spike yield at maturity were studied under the conditions of rice straw retaining with full amount.The results showed that PR increased the stems number per plant at the beginning of over-wintering by 1.5%,12.8%,respectively,compared with RR and NT,with significant differences(P<0.05).Leaf area and dry matter weight per plant under PR were 94 cm^(2)and 787 mg,respectively,which were significantly higher than those under NT(P<0.05).Compared with NT,PR significantly improved activities of nitrate reductase(NR),glutamine synthase(GS),and glutamate synthase(GOGAT)of the top full expanding leaves in the main stem and the first,second,and third tillers(P<0.05).PR also significantly promoted the activities of diphosphate carboxylase(Rubisco),pyruvate phosphate dikinase(PPDK),triosephosphate isomerase(TPI),sucrose synthase(SS-Ⅱ),and sucrose phosphate synthase(SPS),and enhanced SPAD and soluble sugar content(P<0.05).And compared with NT,PR significantly increased the nitrogen content in seedling leaves of main stem,second and third tillers(P<0.05).Moreover,PR and RR increased leaf area and dry matter weight of the main stem and the first and second tillers.Therefore,compared with RR and NT,PR was more beneficial to the synergistic improvement of nitrogen metabolism,glucose metabolism,and light energy utilization at the seedling stage,increasing photosynthetic productivity and forming robust seedlings.The improvement of carbon and nitrogen metabolism and photosynthetic capacity by RR was higher than that by NT but was weaker than that by PR.There were no significant differences between PR and RR in the grain number per spike,single grain weight of the main stem(P>0.05),but they were significantly higher than those under NT(P<0.05).The grain number per spike in the first and second tillers under PR was significantly higher than that under RR and NT(P<0.05),but single grain weight and grain yield per spike of the first,second,and third tillers were not significantly different between PR and RR(P>0.05).In conclusion,PR could improve the activity of glucose and nitrogen metabolism and photosynthetic physiology of the main stem and the first and second tillers of wheat in rice stubble,resulting in the increases of the grain number per spike and the productivity per spike through forming strong seedlings.