腐植酸对番茄苗期氮素代谢的影响

腐植酸对肥料具有改性增效的作用,以番茄为供试材料,研究腐植酸增效剂不同添加量对番茄苗期生长及氮素代谢酶活性的影响,为腐植酸的开发应用提供参考依据。采用砂培试验方法,设置了向霍格兰营养液分别加入腐植酸增效剂0(HA0),1(HA1),2(HA2),5(HA3),10(HA4) mL/L处理。培养30天后,测定番茄的生长指标、植株养分含量、硝酸还原酶活性、谷氨酰胺合成酶和谷氨酸脱氢酶活性。添加适量腐植酸增效剂能促进番茄苗期生长,HA3处理番茄根系干重比HA0提高了31.68%,HA1处理番茄地上部干重最大。添加腐植酸可以提高番茄苗期叶片叶绿素含量,HA3处理番茄苗期叶片叶绿素总量和类胡萝卜素含量最高,分别比HA0提高了17.11%,24.04%。添加适量腐植酸增效剂能增加番茄苗期根系和地上部对氮素的吸收,HA3处理的番茄根系、地上部及总氮素积累量比HA0分别提高了30.61%,20.24%,21.54%。添加腐植酸增效剂可以调控番茄根系和叶片氮素代谢过程,提高了氮素代谢酶活性,与HA0相比,HA4处理根系硝酸还原酶活性最大,HA3处理根系谷氨酰胺合成酶活性最高,HA2处理根系谷氨酸脱氢酶的活性最大;HA3处理番茄苗期叶片中硝酸还原酶、谷氨酰胺合成酶和谷氨酸脱氢酶活性最大,与HA0处理相比分别提高了38.27%,64.54%,106.63%。添加腐植酸增效剂可以促进番茄苗期的生长和对氮素的吸收,提高氮素代谢酶活性,处理中以在营养液中添加5 mL/L腐植酸增效剂效果最佳,腐植酸增效剂添加量低于5 mL/L时,对番茄苗期的生长及氮素代谢具有明显的促进作用。

Effect of Humic Acid on Nitrogen Metabolism at Tomato Seedling Stage

Humic acid could improve the effect of fertilizers. Tomato was used as material in this experiment, the effects of humic acid synergist on the growth of tomato seedlings and the activity of nitrogen metabolism enzymes were studied in order to provide a reference for the development and application of humic acid. In this sand culture experiment, the humic acid was added to Hoagland nutrient solution with 0 (HA0), 1 (HA1), 2 (HA2), 5 (HA3) and 10 mL/L (HA4) respectively with 6 replications for each treatment. After culture for 30 days, the plant growth index, nutrients contents, nitrate reductase activity, glutamine synthase and glutamate dehydrogenase activities were measured. Adding proper amount of humic acid could promote the growth of tomato seedling, and the dry weight of root system of HA3 treatment increased by 31.68% than that of HA0. The dry weight of aboveground of tomato treated with HA3 was the largest. Adding Humic Acid could increase chlorophyll contents in Tomato leaves at the seedling stage. The contents of chlorophyll and carotenoid in tomato leaves treated with HA3 were the highest, which were 17.11% and 24.04% higher than that of HA0, respectively. The addition of proper amount of humic acid could increase the assimilation of nitrogen in roots and shoots of tomato at seedling stage. The accumulation of nitrogen in root, shoot and total nitrogen of tomato treated with HA3 was increased by 20.24% and 21.54% than that of HA0, respectively. The addition of humic acid could regulate the nitrogen metabolism process of tomato roots and leaves, and increase the activities of nitrogen metabolizing enzymes. Compared with HA0, the nitrate reductase activity of roots treated with HA4 was the highest, and the activity of glutamine synthase with HA3 was the highest. The maximum activity of glutamate dehydrogenase was found in root system treated with HA2. The activities of nitrate reductase, glutamine synthase and glutamate dehydrogenase in tomato leaves treated with HA3 were the highest, which increased by 38.27%, 64.54% and 106.63% respectively compared with HA0. The addition of humic acid could promote the growth and absorption of nitrogen and increase the activities of nitrogen metabolizing enzymes at tomato seedling stage. The best effect was found under the addition of 5 mL/L. When the addition was lower than 5 mL/L, it could promote the growth and nitrogen metabolism of tomato seedlings.