不同浓度Fe2+与Zn2+对羊草幼苗生长和生理特性的影响

以羊草幼苗为研究对象，通过调整全营养培养基(CK，0.05 mmol/L Fe²⁺、0.015 mmol/L Zn²⁺)中铁或者锌含量设置0、10倍、20倍Fe²⁺(Zn²⁺)浓度处理Fe₀(Zn₀)、Fe₁₀(Zn₁₀)、Fe₂₀(Zn₂₀)，以及在高铁培养基中单独添加0.15 mmol/L Zn²⁺或同时添加10 mmol/L Ca²⁺、5 mmol/L Mg²⁺、20 mmol/L K⁺处理，测定培养6 d后幼苗生长指标和矿质元素含量、以及高铁(Fe₂₀)处理下幼苗根中抗氧化指标和相关基因表达量，探究不同浓度Fe²⁺、Zn²⁺对羊草幼苗生长、矿质元素吸收积累及抗氧化指标、基因表达的影响。结果表明：(1)缺锌(Zn₀)显著抑制羊草幼苗鲜重的增加和Zn元素的积累，但促进Fe、Mg元素的积累；高浓度锌(Zn₁₀、Zn₂₀)显著促进幼苗叶片生长和Zn元素的积累；缺铁(Fe₀)显著抑制幼苗的根长、鲜重和Fe元素的积累，促进Mg、Zn元素的积累；高浓度铁(Fe₁₀、Fe₂₀)显著抑制羊草幼苗根叶生长、根毛发育和Ca、Zn、Mg、K元素的积累。(2)增加Zn²⁺和Ca²⁺、Mg²⁺、K⁺浓度无法恢复高铁胁迫对幼苗生长的抑制作用。(3)高浓度铁(Fe₂₀)处理羊草幼苗48 h后，根部过氧化物酶、超氧化物歧化酶、过氧化氢酶、抗坏血酸过氧化物酶、谷胱甘肽还原酶活性和丙二醛、抗坏血酸、还原型谷胱甘肽含量显著升高；烟酰胺合成酶基因、过氧化物酶基因表达量显著下调，植物类萌发素蛋白基因表达量显著上调。研究发现，羊草幼苗生长发育和矿质元素积累对环境中Zn²⁺浓度变化不敏感，却受到环境中高浓度Fe²⁺的显著抑制，并造成严重的氧化胁迫伤害，这种伤害无法在添加Zn²⁺或同时添加Ca²⁺、Mg²⁺、K⁺的条件下恢复。

Effect of Different Concentrations of Fe2+ and Zn2+ on Growth and Physiological Characteristics of Leymus chinensis Seedlings

With Leymus chinensis seedlings as the research object, we set 0, 10 and 20 times Fe²⁺ (Zn²⁺) concentration by adjusting the contents of iron and zinc in total nutrition medium (CK: 0.05 mmol/L Fe²⁺, 0.015 mmol/L Zn²⁺) as Fe₀ (Zn₀), Fe₁₀ (Zn₁₀), Fe₂₀ (Zn₂₀). And adding 0.15 mmol/L Zn²⁺ alone or 10 mmol/L Ca²⁺, 5 mmol/L Mg²⁺, 20 mmol/L K⁺ to the high concentration iron medium at the same time. We measured the growth index and mineral element contents of seedlings after 6 days of culture, as well as the antioxidant indexes and related gene expression in the roots of seedlings treated with high concentration iron (Fe₂₀), to explore the effects of different concentrations of Fe²⁺ and Zn²⁺ on the growth, mineral element absorption and accumulation, antioxidant indexes and gene expression in Leymus chinensis seedlings. The results show that: (1) deficiency of Zn (Zn₀) significantly inhibited the increase of fresh weight and the accumulation of Zn elements, but promoted the accumulation of Fe and Mg elements. High concentration of Zn (Zn¹⁰, Zn²⁰) significantly promoted the growth of seedling leaves and the accumulation of Zn. Deficiency of Fe(Fe₀) significantly inhibited the root length, fresh weight and the accumulation of Fe elements, and promoted the accumulation of Mg and Zn elements in seedlings. High concentration of Fe(Fe₁₀, Fe₂₀) significantly inhibited the root and leaf growth, root hair development and the accumulation of Ca, Zn, Mg and K elements in L. chinensis seedlings. (2) Increasing the concentration of Zn²⁺ and Ca²⁺, Mg²⁺, K⁺ could not restore the inhibitory effect of high concentration iron stress on seedling growth. (3) After treatment of L. chinensis seedlings with high concentration of iron (Fe₂₀) for 48 hours, the activities of peroxidase, superoxide dismutase, catalase, ascorbate peroxidase, glutathione reductase and the contents of malondialdehyde, ascorbic acid and reduced glutathione in roots increased significantly, while the gene expressions of nicotianamine synthase and peroxidase were down regulated significantly and plant germinin like protein were up regulated significantly. The research found that the growth and development of L. chinensis seedlings and the accumulation of mineral elements were not sensitive to the change of Zn²⁺ concentration in the environment, but were significantly inhibited by the high concentration of Fe²⁺ in the environment, and caused serious oxidative stress damage, which this damage cannot be recovered under the conditions of adding Zn²⁺ or adding Ca²⁺, Mg²⁺, K⁺ at the same time.