不同养分配比对高粱根系生长及养分吸收的影响

Effect of different nutrient combinations on root growth and nutrient accumulation in sorghum

  • 摘要: 为探明高粱养分吸收和根系生长对氮、磷、钾胁迫的响应,通过长期定位试验,在高粱/玉米轮作条件下研究了不同养分配比NPK、PK、NK、NP、CK对高粱根系生长及养分吸收的影响。结果表明:与NPK相比,长期不施氮肥(PK)条件下高粱总根长增加18.29%,总根体积降低26.52%,且根系主要分布在0~10 cm土层,直径小于0.5 mm细根所占比例显著增加。不施磷肥(NK)显著抑制了高粱根系生长,总根长、总根表面积和总根体积分别降低24.03%、27.48%和41.29%。不施钾肥(NP)对细根生长有明显抑制作用。不施氮、磷、钾均降低高粱对相应养分的吸收和累积,不施氮促进了营养器官中氮和钾素向籽粒转运,不施磷或钾肥抑制了氮、磷及钾的转运。高粱对养分的吸收、积累和转运与根系形态有关,不同养分积累与运转与根系形态关系表现不尽相同:氮素、钾素积累和转运与根系形态具有较好的相关性,氮素的积累和转运与植株生物量和产量的相关性大于磷素和钾素。综上,高粱根系形态及养分吸收对氮、磷及钾胁迫响应不同,该研究可为不同养分瘠薄地高粱高效栽培提供理论依据。

     

    Abstract: Sorghum, one of the important grains in the world, can grow well in low fertility soils. In order to understand the response of nutrient accumulation and root growth in sorghum to N, P and K stresses, a long-term experiment consisting of 5 treatments (NPK, PK, NK, NP and CK) under conditions of sorghum/maize rotation system was initiated in 2011. The indi-vidual treatments of the experiment ensured differences in availability of soil N, P and K before sowing sorghum in 2016. The results showed that compared with NPK treatment, PK treatment increased total root length by 18.29% and decreased total root volume by 26.53%. Also under PK treatment, sorghum root distribution was mainly in the 0-10 cm soil layer. The proportion of fine roots with diameter less than 0.5 mm increased significantly under PK treatment. Compared with NPK, total length, total surface area and total root volume of sorghum decreased respectively by 24.03%, 27.48% and 41.29% under NK treatment. Without K (i.e. under NP treatment), the growth of fine roots was inhibited. Removal of either N or P or K decreased the accumulation of the corresponding element in sorghum. It was recommended not to induce N or limit N and K translocation from vegetative organs to grains. Both the combinations NK and NP inhibited the transfers of N, P and K to grain from vegetative parts. The accumulation and translation of N, P and K were regulated by root morphology. There were significant relationships between both N and K accumulation and individual root parameter (total root length, total root surface area and total root volume). Compared with P and K accumulation, N accumulation in sorghum had an obviously correlation with both N translocation from vegetative organs to grains and aboveground biomass. In summary, the response of root morphology and nutrient accumulation in sorghum to individual N, P or K stress was different. The results were useful for the cultivation of sorghum in marginal soils.

     

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