鸭茅幼苗生长及形态对铝胁迫的响应

选取我国西南地区的鸭茅(Dactylis glomerata)主栽品种‘德纳塔’、‘安巴’、‘宝兴’和‘牧友’为供试材料,研究酸性环境下不同梯度的铝离子(0,10,30,50和100 μM)对鸭茅幼苗生长及形态的影响。结果表明:铝胁迫下,鸭茅枝条干重、根系干重、植株形态及根系伸长均受到显著抑制,且随着浓度的增加呈现出下降趋势;低浓度(10～30 μM)铝离子处理对鸭茅生长造成的抑制较弱,对鸭茅植株的健康形态塑造没有造成影响;而高浓度(≥50 μM)铝离子处理则对鸭茅植株根系伸长和植株形态造成严重的抑制,不利于植株后期的健康生长;供试鸭茅地下部根系积累铝的量要大于地上部枝条,且品种间存在一定差异,‘牧友’根系中铝含量最低,耐受性较强。表明鸭茅通过改变植株形态和调控自身积累铝的水平来应对酸性土壤中的铝离子胁迫,但是酸性铝离子环境对鸭茅早期生长仍具有一定的毒害作用,低浓度造成的影响较小,而高浓度则对鸭茅植株生长和形态塑造均造成不良的影响。

Response of Seedling Growth and Morphology of Orchardgrass to Al Stress

The several varieties of orchardgrass (Dactylis glomerata‘Donata’, ‘Amba’, ‘Baoxing’ and ‘Potomac’) were main planted in the southwest of China and the five concentrations of aluminum ion 0 (the control), 10, 30, 50 and 100 μM] were designed as Al stress. The effects of aluminum stress on the seedling growth and morphology of orchardgrass were studied in hydroponic solution with pH 4.5. The results indicated that the shoot biomass, root biomass, seedling morphology and root elongation of orchardgrass were inhibited obviously under Al stress. And with the increase of aluminum ion concentration, the above indicators of orchardgrass seedling presented a decreasing trend. The low concentration of Al treatment (10～30 μM) had weaker inhibition effect on the plant morphology of orchardgrass seedling and no harmful effect on forming a health plant shape, whereas the higher concentration of Al treatment (≥50 μM) had inhibition effect on the root elongation and root morphology of orchardgrass seedling and was harmful to plant health growth in the future. The accumulating aluminum levels of orchardgrass seedling shoot and root under Al stress were different. The concentration of accumulating aluminum in root was more than shoot. There were also different tolerance levels to aluminum stress among tested varieties. ‘Potomac’ variety was more tolerant to aluminum stress and the concentration of accumulating aluminum was lower in ‘Potomac’ root than others. It was concluded that orchardgrass was tolerant to aluminum stress by changing plant morphology and regulating the level of accumulating aluminum. However, aluminum ion in acid soil was still harmful to the early growth of orchardgrass that was less affected by the lower concentration of aluminum ion and serious inhibited by the higher concentration of aluminum ion.