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用容重分别为1.25 g·cm~(-3)(疏松土壤,对照)和1.55 g·cm~(-3)(紧实土壤)的土壤进行盆栽试验,研究了土壤紧实胁迫对‘津春4号’黄瓜不同生育期根系生长、呼吸速率、活力及氮代谢的影响.结果表明:在土壤紧实胁迫条件下,黄瓜不同生育期根系总长度、表面积、分根数和根尖数均显著下降,根系的伸长生长及侧根的发生受到显著抑制,而根系的加粗生长得到激发,平均直径显著增加;根系活力和根系呼吸速率显著下降;根系中的NO_3~-、游离氨基酸和可溶性蛋白含量大幅下降,硝酸还原酶、谷氨酰胺合成酶和谷氨酸合酶活性显著降低,NH_4~+含量显著增加.说明在土壤紧实胁迫条件下黄瓜根系对硝态氮的吸收量减少,氨同化作用受到抑制,氮代谢显著受阻.
Pot experiments were conducted with soils containing 1.25 g · cm ~ (-3) (loose soil, control) and 1.55 g · cm ~ (-3) (compacted soil) respectively. 4 on the growth, respiration rate, vitality and nitrogen metabolism of cucumber at different growth stages.The results showed that the total length, surface area, root number and root number of cucumber in different growth stages were significantly different under soil compaction stress Decreased, root elongation and lateral root development were significantly inhibited, while root growth was stimulated bold, the average diameter increased significantly; root activity and root respiration rate decreased significantly; roots NO_3 ~ -, free amino acids and soluble protein Content of nitrate reductase, glutamine synthetase and glutamate synthase activity decreased significantly, and the content of NH 4 + increased significantly, which indicated that the root absorption of nitrate in cucumber decreased under soil compaction stress. Assimilation was inhibited, nitrogen metabolism was significantly blocked.