种子库容与外源养分对苗期玉米同化物积累与养分利用的影响

Effect of seed reserve and external nutrient supply on assimilate accumulation and nutrient utilization of maize (Zea mays L.) seedling

【目的】研究种子库容及外源养分对苗期玉米同化物积累的影响及其对养分利用的贡献。【方法】采用育苗移栽和砂培模拟培养的方法,研究种子粒质量(高、中和低)、1叶1心期摘除残余种子终止种子营养(以下简称摘除种子)以及外源养分对苗期杂交玉米鲁单9002和郑单958不同部位生物量、氮、磷、钾含量及累积量的影响。【结果】种子粒质量、摘除种子及外源养分3个因素均明显影响玉米植株生物量的积累和养分含量。其中摘除种子的主效应最强,是郑单958植株和根系生物量、叶氮含量以及鲁单9002根系生物量变化的主要诱因,其次为外源养分。在无外源养分的条件下,不摘除种子郑单958的植株生物量随粒质量的增加而呈递增趋势,鲁单9002则以中粒质量种子育成苗的生物量最高;供给外源养分后则明显提高了2个品种玉米的植株生物量,也改变了同化物在玉米不同部位的分配比例,使中粒质量种子育成苗的植株生物量达到最高(摘除种子郑单958除外)。种子粒质量对不摘除种子郑单958的高粒质量种子育成苗的生物量累积以及2个品种玉米不摘除种子的高粒质量种子育成苗的养分累积的贡献均高于中和低粒质量种子育成苗。此外,种子对不摘除种子郑单958的生物量、氮和磷累积的贡献总体上高于不摘除种子鲁单9002。【结论】郑单958能更充分地利用种子中贮存的养分,降低苗期玉米对外源养分的依赖,这是其和大库容种子具有生态广适性的主要原因之一。

【Objective】The aim of this study was to evaluate the contribution of seed reserve and exogenous nutrient supply to assimilate accumulation and nutrients utilization of maize seedlings.【Method】Effects of seed weight(high-,middle-,and low-weight seeds),removal of both seed coat and endosperm(de-endosperm),and exogenous nutrient supply on biomass and contents and accumulation of nitrogen,phosphorus and potassium at different parts of transplanted seedlings of maize(Zea mays L.)Zhengdan958and Ludan 9002 were investigated using sand culturing experiment.【Result】The three factors exerted statistically significant impacts on total biomasses and nutrients contents of the two maize hybrids.De-endosperm showed the highest single main effect,which was the main reason for changes in total plant androot biomasses and nitrogen content in leaves of Zhengdan 958 and root biomass of Ludan 9002,followed by exogenous nutrient supply.Total biomass of Zhengdan 958 supplied with distilled water increased with the increase of seed weight.Cultivars Ludan 9002 cultivated from middle-weight-seed showed the highest biomass.Exogenous nutrients supply significantly increased total biomasses of the two cultivars and changed assimilates distribution among different parts compared to the plants supplied with distilled water.Thus,seedlings cultivated from middle-weight-seed and supplied with nutrient solution showed the highest biomasses.Seedlings from high-weight-seed of the two keep-endosperm-cultivars utilized seed nitrogen and phosphorus reserves more sufficiently than seedlings from middle-weight-seed and low-weight-seed.Furthermore,biomass and accumulation of nitrogen and phosphorus in keep-endosperm-Ludan 9002 were more susceptible to exogenous nutrient supply than those in keep-endosperm-Zhengdan 958.【Conclusion】Zhengdan 958 utilized the nutrients in seed more sufficiently and reduced the nutrient requirement from exogenous sources,which was the main reason for wide ecological fitness of Zhengdan 958 and high-weightseed seedlings.