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Schrader 等(1972)曾报道,NO_3~-和 NH_4~+的结合处理对促进玉米生长比单一形式处理更为有利。Lüttge 等(1979)也指出,阴离子/阳离子的吸收比值不平衡可使植株体内产生OH~-或 H~+过剩,进而影响某些有机酸合成酶的活性。Aducci 等(1982)认为,细胞质的 pH值对 N 吸收起调控作用。在低氧条件下,三羧酸循环和电子传递系统均不运行,糖酵解作用则成为 ATP 的唯一来源。丙酮酸必须还原成乳酸或乙醇,使 NAD 得以再生。由乳酸发酵引起的细胞质酸化可使其核磁共振谱中细胞质的~(31)P 信号产生一个向右的位移,而且根据磷酸糖信号强度的降低可判断糖酵解作用的加强。本试验用核磁共振(NMR)谱仪研究了不同的 N 形态(NO_3~-,NH_4~+
Schrader et al. (1972) reported that the combined treatment of NO_3 ~ - and NH_4 ~ + was more favorable than the single treatment for corn growth. Lüttge et al. (1979) also pointed out that an imbalance in the absorption ratio of anions / cations may cause OH ~ - or H ~ + excess in the plant, thereby affecting the activity of some organic acid synthases. Aducci et al (1982) that the cytoplasmic pH on N absorption regulation. Under hypoxic conditions, neither the tricarboxylic acid cycle nor the electron transport system is functioning, and glycolysis alone becomes the sole source of ATP. Pyruvate must be reduced to lactate or ethanol to regenerate NAD. Cytosolic acidification caused by lactic acid fermentation can produce a rightward shift in the cytoplasmic ~ (31) P signal in the nuclear magnetic resonance spectrum, and the enhancement of glycolysis can be judged according to the decrease of the phosphosugar signal intensity. In this experiment, different N forms (NO 3 -, NH 4 +