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以平邑甜茶幼苗为试材,运用~(15)N同位素示踪和非损伤微测技术,研究了不同供硼(硼酸0、1.0、2.0、3.0、4.0、5.0和6.0 mg·L~(-1))水平对平邑甜茶根系生长及氮素吸收、利用和分配特性的影响。结果表明,3.0 mg·L~(-1)硼酸处理的幼苗根系活力及根系形态指标显著高于其他处理,幼苗的全氮量及~(15)N吸收量增幅最大,分别比对照提高了19.4%和75.0%。随供硼水平的增加,植株氮素利用率呈现先增高后降低的趋势,在3.0 mg·L~(-1)硼酸处理时最大,为14.8%,是对照的1.8倍。施硼处理对幼苗的~(15)N分配率有一定的影响,3.0 mg·L~(-1)硼酸处理的根系~(15)N分配率达到最大,且显著高于对照。非损伤微测结果显示,3.0 mg·L~(-1)硼酸处理时,平邑甜茶根系对NO_3~-有强烈吸收且内流速度达到最大,在缺硼和高硼(硼酸0和6.0 mg·L~(-1))处理时有明显外排趋势。因此,3.0 mg·L~(-1)硼酸处理最有利于平邑甜茶根系的生长、根系活力的提高和氮素的吸收利用,而低硼和过量供硼均会抑制根系生长及氮素的吸收利用。
The seedlings of Eupatorium triticum were used as experimental material, and the effects of different boron donors (boric acid 0, 1.0, 2.0, 3.0, 4.0, 5.0 and 6.0 mg · L ~ (-1) -1)) on the root growth, nitrogen absorption, utilization and distribution of P. euphratica. The results showed that the root vigor and root morphology of seedlings treated with 3.0 mg · L -1 boric acid were significantly higher than those of other treatments, and the total nitrogen and the uptake of 15 N increased most significantly % And 75.0%. With the increase of boron supply, the nitrogen utilization efficiency of plants increased firstly and then decreased, the highest was 14.8% when treated with 3.0 mg · L -1 boric acid, which was 1.8 times of the control. Boron treatment had some effect on the distribution rate of ~ (15) N in seedlings, and the distribution rate of ~ (15) N in roots treated with 3.0 mg · L -1 boric acid reached the maximum, which was significantly higher than that of the control. The results of non-invasive micro-analysis showed that when 3.0 mg · L -1 boric acid was added, the roots of Malus hupehensis strongly absorbed NO 3 - and the inflow velocity reached the maximum. Under boron deficiency and high boron (boric acid 0 and 6.0 mg · L ~ (-1)). Therefore, the treatment with 3.0 mg · L -1 boric acid was most beneficial to root growth, root activity and nitrogen uptake, while low boron and excess boron all inhibited root growth and nitrogen Absorption and utilization.