钾水平对不同基因型斑茅生长和钾营养特性的影响

Effects of potassium levels on plant growth and potassium nutrition characteristics of Erianthus arundinaceum

[目的]探讨不同钾水平下3个基因型斑茅根系形态和钾营养特性的差异,为培育钾高效甘蔗品种提供优异种质和理论依据。[方法]以钾钝感斑茅材料云南82-85和钾敏感斑茅材料海南92-109、广西87-3为供试材料,采用高钾(3 mmol·L-1,HK)和低钾(0.1 mmol·L-1,LK)2个营养液培养方法,研究钾素对不同基因型斑茅生长、根系形态、钾素累积和利用效率的影响。[结果]在低钾处理下,云南82-85地上部和根系干质量均低于高钾处理;海南92-109和广西87-3则不同,地上部干质量均低于高钾处理,分别为高钾处理的69.20%和76.76%,而根系干质量则高于高钾处理,分别为高钾处理的1.22和1.06倍。云南82-85在低钾和高钾处理下根系形态参数和根冠比均无显著差异,而海南92-109和广西87-3在低钾处理下根系总长、表面积、体积和根冠比均显著高于高钾处理。表明低钾胁迫促进了钾敏感材料海南92-109和广西87-3根系生长,增大了吸收面积。此外,广西87-3和海南92-109在低钾和高钾处理下,其根系钾含量均低于云南82-85,而地上部钾含量在高钾处理下显著高于云南82-85,分别高出1.2和1.3倍,达显著水平;在高钾和低钾处理下,这两个材料地上部和植株钾累积量均显著高于云南82-85。与钾敏感斑茅材料海南92-109和广西87-3相比,钾钝感斑茅材料云南82-85的钾素吸收、转运和利用效率均较低。[结论]在低钾胁迫条件下,钾敏感斑茅材料以较为发达的根系和更高效的钾素转运能力适应低钾胁迫。

[ Objectives] The aim of this study was to investigate the differences in the root morphology and potassium nutrition charac- teristics of different genotypes of Erianthus arundinaceum under the different potassium levels, and to apply the superior sugarcane germplasm resources and offer a theoretical basis for breeding potassium high efficient sugarcane varieties. [ Methods ] One low-K tolerant E. arundinaceum genotype named Yunnan82-85 and two low-K sensitive E. arundinaceum genotypes named Hainan92-109 and Guangxi87-3 were used as the testing materials. Two potassium levels, high （ 3.0 mmol·L^-1 K＋, HK ） and low （ 0.1 mmol·L^- 1 K＋, LK ） were set up under the nutrient culture. Plant height, dry weight,potassium content and accumulation in each part of E. arundinaceura, root morphological traits and potassium use efficiency were studied. [ Results ] The low K^＋ stress led to significantly decreasing shoot and root dry weight of Yunnan82-85 compared with high K^＋ level. Shoot dry weight of Hainan92-109 and Guangxi87-3 grown in low K^＋ solution were 69.20% and 76.76% of those grown in high K^＋ solution ,whereas root dry weight were 1.22 and 1.06 times more than those in high K^＋ solution,respectively. There was no change in the morphological traits and the ratio of root/shoot of Yunnan82-85 under low and high K^＋ level. Root total length, surface area, volume and the ratio of root/shoot of Haiuan92-109 and Guangxi87-3 grown in low K^＋ solution were higher than those grown in high K^＋ solution. Low K^＋ condition increased the root development of the genotypes Hainan92-109 and Guangxi87-3 sensitive to potassium. In addition, the K contents in root of Hainan92-109 and Guangxi87-3 were lower than those of Yunnan82-85 under both low and high K^＋ level ,but the K contents in shoot of Hainan92-109 and Guangxi87-3 were 1.2 and 1.3 times higher than those of Yunnan82-85 under high K^＋ solution, respectively. Additionally, the potassium accumulations in shoot and whole plant of Hainan92-109 and Guangxi87-3 were significantly higher than those of Yunnan82-85. The low-K tolerant E. arundinaceum genotype Yunnan82-85 were lower in the potassium absorption,transport and utilization efficiencywhen compared with the low-K sensitive genotypes （e. g. Hainan92-109 and Guangxi87-3）. [ Conclusions] Our results suggested that the low-K sensitive E. arundinaceum genotypes had the bigger root dry weight and the better ability of potassium transportation to adapt the low K＋ stress.