水氮耦合对红小豆根系生理生态及产量的影响

Effects of coupling water and nitrogen on root physio-ecological indices and yield of adzuki bean

  • 摘要: 采用盆栽称重全生育期控水法研究了不同水分(干旱胁迫与正常灌水)和施氮(纯氮用量分别为0 g·kg-1、0.1 g·kg-1、0.3 g·kg-1)组合处理对红小豆根系生理生态指标及产量的影响, 为红小豆在黄土高原高产优质栽培提供理论依据。结果表明: 1)在干旱胁迫条件下, 红小豆苗期株高、茎粗、地上部干重、总根长、根表面积、根系体积、根系平均直径、最大根长、根系干重、壮苗指数、根系可溶性蛋白质含量, 开花结荚期净光合速率、蒸腾速率、气孔导度以及成熟期豆荚横径、单荚重、单荚粒数、百粒重均随施氮量的增加呈先升高后降低的趋势, 除根表面积和荚横径外, 0.1 g·kg-1施氮处理各指标均显著高于其他处理; 根系SOD和POD活性随施氮量的增加而增加, 0.3 g·kg-1施氮处理与其他处理间差异显著; 根系可溶性糖含量随施氮量的增加呈先降低后升高的趋势, 0.1 g·kg-1施氮处理显著低于其他处理; 但根系MDA含量、豆荚荚长和单株荚数对氮素并不敏感。在正常灌水条件下, 最大根长随施氮量的增加而降低; 根系SOD、POD活性和气孔导度随施氮量的增加而增加, 且0.3 g·kg-1施氮处理显著高于其他处理; 根系MDA含量和可溶性糖含量随施氮量的增加呈先降低后升高的趋势, 0.1 g·kg-1施氮处理显著低于其他施氮处理; 单株荚数对氮素不敏感外, 其余各豆荚性状和产量指标均随施氮量的增加呈先升高后降低的趋势, 且除荚横径外, 0.1 g·kg-1施氮处理各豆荚性状和产量指标显著高于其他处理。2)在相同施氮条件下, 随着灌水量的增加, 除根系SOD和POD活性、根系可溶性糖和可溶性蛋白质含量降低, 根系MDA含量、荚横径和单株荚数对水分不敏感, 其余各指标均呈增加趋势, 且除茎粗、地上部干重、根系平均直径、根系可溶性蛋白质含量、荚长和单荚粒数外, 不同水分处理间差异均达显著水平。3)无论水分条件如何, 0.1 g·kg-1的施氮处理下红小豆产量最高, 与其他施氮处理相比, 在干旱胁迫和正常灌水条件下的增产幅度分别为95.2%~118.3%和63.8%~137.1%; 在施氮量一定的情况下, 正常灌水处理比干旱胁迫处理增产84.5%~198.7%。研究表明, 合理的水氮管理有利于红小豆植株的生长发育和产量形成, 红小豆在旱薄胁迫并存的山西黄土高原丘陵区更适合在低水中肥条件(土壤含水量保持在田间持水量的35%~45%, 施纯氮量为0.1 g·kg-1)下种植。

     

    Abstract: The process of water regulation during the growing period of adzuki bean under experimental pot conditions was studied in order to determine the effects of combining different water (drought stress and normal irrigation) and nitrogen fertilizer (N application rates of 0 g·kg-1, 0.1 g·kg-1, and 0.3 g·kg-1) conditions on the root physio-ecological indices and yield. The results showed that: 1) Under drought stress condition, plant height, stem diameter, shoot dry weight, total root length, root area, root volume, average root diameter, max root length, root dry weight and seedling index initially increased and then decreased with increasing nitrogen application rate. Also root soluble protein content at seedling stage, Pn, Tr and Gs at blooming/pod-setting stage, transverse diameter, weight per pod and seeds per pod, 100-seed weight at mature stage initially increased and then decreased with increasing nitrogen application rate. Furthermore, the activities of SOD and POD in root increased with increasing nitrogen rate while soluble sugar content decreased initially and then increased with increasing nitrogen application rate. However, root MDA content, pod length and pods per plant did not significantly change in response to different nitrogen fertilizer treatments. Under normal irrigation, with increasing nitrogen application rate, maximum root length decreased. Also while SOD activity, POD activity and Gs increased, MDA content and soluble sugar content decreased initially and then increased with increasing nitrogen application. Then pods per plant did not change for three nitrogen treatments while the other indices mentioned above changed parabolically with increasing nitrogen application rate. 2) Under equal nitrogen fertilizer treatments, normal irrigation decreased SOD and POD activities, soluble sugar content and soluble protein content as opposed to drought stress treatment. However, MDA content, transverse diameter and pods per plant had no significant difference for both drought and normal irrigation conditions. The other above indices increased under normal irrigation treatment compared with drought stress treatment. 3) Among the three nitrogen levels, yield of adzuki bean was highest under 0.1 g·kg-1 nitrogen application. It increased respectively by 95.2% and 118.3% compared with 0 g·kg-1 and 0.3 g·kg-1 nitrogen treatments under drought stress condition. It also increased respectively by 63.8% and 137.1% compared with 0 g·kg-1 and 0.3 g·kg-1 nitrogen treatments under normal irrigation condition. In addition, yield of adzuki bean was higher in normal irrigation treatment. It increased by 84.5% and 198.7%, respectively, compared to drought stress treatment under equally nitrogen fertilizer treatment. The results suggested that reasonable application of nitrogen fertilizer and water enhanced the growth and yield of adzuki bean, furthermore, adzuki bean was more suitable for production at low soil moisture (35%–45% of field water capacity) and suitable fertilizer condition (0.1 g·kg-1 N application) in the hilly area of Loess Plateau of Shanxi Province.

     

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