低钾胁迫对大豆根系渗透调节物质及产量影响

Effect of low potassium stress on osmotic adjustment substances of root and yield in soybean

以耐低钾型大豆铁丰40(T40)、WM和低钾敏感型大豆GD8521为材料,研究低钾胁迫下大豆根系K+、可溶性糖、脯氨酸和游离氨基酸等渗透调节物质含量变化及其对产量影响。结果表明,低钾胁迫下大豆根系K+、可溶性糖含量下降,而脯氨酸和游离氨基酸含量升高。在出苗后90 d(R6),与低钾敏感型大豆GD8521相比,耐低钾型大豆T40和WM根系K+含量变化幅度较小,在低钾处理下分别比HK(对照)降低57.02%和50.93%,而GD8521为69.15%;可溶性糖、脯氨酸和游离氨基酸含量变化幅度较大,T40和WM低钾处理根系游离氨基酸含量分别比HK(对照)升高54.67%和48.94%,而GD8521为41.02%。低钾处理下,T40和WM产量降低幅度较小,比对照分别下降37.06%和46.34%,差异不显著(P>0.05);而GD8521产量下降幅度较大,为64.77%,差异达显著水平(P<0.05)。说明耐低钾型大豆品种可维持根系K+含量相对稳定,糖转化为淀粉能力更强,有较高的脯氨酸和游离氨基酸含量维持细胞渗透势,保证其渗透调节能力并稳定产量。

Throe representative soybean varieties Tiefeng40 （T40）, WM （tolerance to K deficiency） and GD8521 （sensitive to K deficiency） were grown in field to measure the K, soluble sugar, free proline and free amino acids content to investigate the effects on osmotic adjustment substances in roots and yield of different tolerance soybeans under low potassium stress. The results showed that the K＊ and soluble sugar content of soybeans roots decreased and the proline and free amino acids content increased under low potassium stress. Compared with GD8521, the K＊ content in T40 and WM roots changed to a less extent, which reduced by 57.02% and 50.93% compared with HK treatment in 90 d after emergence（R6）, which GD8521 was 69.15%; the soluble sugar, free proline and free amino acids content changed to a higher extent, such as the free amino acids content of T40 and WM roots reduced by 54.67% and 48.94% compared with HK treatment in 90 d after emergence, which GD8521 was 41.02%. The yield of T40 andWM had a smaller change range than GD8521, which T40, WM and GD8521 reduced by 37.06%（P〉0.05）, 46.34% （P〉0.05） and 64.77% （P〈0.05） compared with HK treatment. It was suggest that T40 and WM could maintain the root K＋ content stable, its ability to convert soluble sugars to starch was stronger than that of GD8521, the free preline and free amino acid contents were at a higher level which could maintain cellular osmotic potential to ensure the ability of osmotic adjustment, and then had a more stable yield.