净、套作下大豆茎秆和籽粒糖氮动态规律研究

碳氮代谢是影响作物产量和品质的主要因素之一,在糖氮运输和储存过程中茎秆起着重要作用。以南豆12和南豆20为供试材料,在净、套作下分析不同生育时期大豆茎秆及籽粒中可溶性糖、氮含量变化规律,明确种植模式对大豆茎秆和籽粒碳氮的影响。结果表明,随着生育时期的推进,南豆12和南豆20茎秆可溶性糖和氮含量在净、套作条件下均呈现"低-高-低"的趋势,糖氮比呈现"低-高"的趋势。大豆从苗期至盛花期,茎秆可溶性糖、氮及糖氮比在净套作条件下差异显著(P0.05),但从盛荚期至完熟期差异不显著(P0.05)。净、套作模式下大豆籽粒可溶性糖、氮含量及糖氮比差异极显著(P0.01),但品种间差异不显著。通过相关性分析,大豆盛花期到鼓粒期茎秆可溶性糖、氮含量及糖氮比与籽粒可溶性糖、氮含量及糖氮比相关性达到显著水平(P0.05),特别是氮和糖氮比,相关系数最大值达到0.85。这些结果为明确糖氮由茎秆到籽粒的运输规律和套作大豆合理种植栽培参数提供理论支撑。

Dynamics of soluble sugar and nitrogen contents in the stem and grain of soybean under relay intercropping and monoculture conditions

Carbon and nitrogen metabolisms play critical roles in plant growth and development and are closely related to crop yield and grain quality.The stem plays an important role in transporting and storing sugar and nitrogen in a plant.Two typical genotypes of soybean,Nandou 12 and Nandou 20,were used as experimental materials in monoculture and relay intercropping patterns.Under intercropping,soybean was alternatively sown with maize at wide-narrow intervals.The dynamics of soluble sugar and nitrogen contents in the soybean stem and seed were analyzed at different growth stages.In the stem,soluble sugar and nitrogen contents changed in a ‘low-high-low’ trend with stem growth.However,the ratio of soluble sugar to nitrogen contents appeared as a ‘low-high’ trend under monoculture and relay intercropping conditions.Significant differences in stem soluble sugar,nitrogen contents and their ratio under monoculture and intercropping were measured from seedling to full bloom stages (P＜0.05),while after that stage no significant differences were measured in either planting pattern (P＞0.05).In addition,there were significant correlations between soluble sugar,nitrogen contents and the ratio between the stem and seed from full bloom to seed filling stages,notably for nitrogen content and the ratio,where the maximum correlation coefficient was 0.85.This study thus shows that carbon and nitrogen metabolisms after full bloom stage are closely related to crop yield and grain quality under relay intercropping and monoculture conditions,providing theoretical support for a better understanding of plant transportation of carbon and nitrogen from stem to seed and guidance for effective planting under relay intercropping systems.