不同用量风化煤腐殖酸对玉米根系的影响

Response of Maize Roots to Different Additive Amounts of Weathered Coal Humic Acids

【目的】我国风化煤腐殖酸储量丰富,腐殖酸含有多种活性官能团,其对植物生长发育具有重要意义。当腐殖酸施于土壤时,根系对腐殖酸的响应是促进植物生长的最初动力。因此,研究腐殖酸对玉米根系生长发育的影响机制,可为风化煤腐殖酸资源的高效利用和作物的增产提质提供理论依据。【方法】采用霍格兰营养液溶液培养试验,供试玉米品种为郑单958,待玉米幼苗长至两叶一心时移到营养液培养盆钵中缓苗1 d,外源添加不同添加量(0、5、10、15和20 mg C·L^(-1))腐殖酸,研究其对玉米生物量、根冠比、根系形态以及根部养分状况的影响。【结果】(1)腐殖酸可显著增加玉米根系和地上部干物质量、根冠比、根系活力和根系TTC还原总量,较对照分别平均提高42.31%、19.33%、18.18%、46.54%和81.01%。(2)腐殖酸可改善玉米根系的形态,其处理玉米总根长、总根数量、根体积、根表面积和平均直径分别比对照平均提高13.51%、16.74%、69.62%、14.68%和49.28%。(3)添加腐殖酸可增加玉米根系的轴根数、轴根长度和侧根数,腐殖酸处理分别比对照提高16.28%、21.65%和16.80%。(4)随腐殖酸添加量的增加,对玉米根系生长的促进作用呈现先升高后降低的变化,以中等浓度(10 mg C·L^(-1))腐殖酸对玉米根系的作用效果最明显,其根干物质量和根系活力分别比对照提高了69.36%和69.07%。(5)腐殖酸处理(尤其是10 mg C·L^(-1))可有效增加玉米根系糖类、碳水化合物、脂类物质、蛋白质、多肽和氨基酸类物质等的含量。【结论】添加腐殖酸可明显增加玉米干物质量和根系活力,增加根冠比,改善根系形态,有效增加玉米根系主要化学组分的含量。本试验条件下,中等浓度(10 mg C·L^(-1))的腐殖酸对玉米根系的促进作用最好。

【Objective】Weathered coal humic acid possesses abundant reserves in China, which has multiple active functional groups. The response of roots to humic acid, which acts as a humic acid acting on the first contact organ of plant, is the initial motive force to promote plant growth. Hence researching the effect of humic acid on the growth and development of maize roots is of significance for crops’ production increase and quality improvement, and can provide a theoretical basis for the effective utilization of weathered coal resource of China. 【Method】Zhengdan958 maize cultivar was used as the tested cultivar, and Hogland nutrient solution hydroponics was adopted in this experiment. When maize seedlings grew to two leaves and one terminal bud, they were moved to the hydroponic basin for one day for readaption time. Then, the effect of applying different concentrations of humic acid(0, 5, 10, 15, and 20 mg C·L-1) on the growth of maize biomass, root-shoot ratio, root systematic architecture and root nutrient were studied. 【Result】(1) Humic acids could significantly increase the root dry weight, shoot dry weight, root-shoot ratio, root activity, and root TTC reducing amount of maize roots. Compared with the control treatment(0 humic acid), the average value of the above indicators with humic acid treatment increased by 42.31%, 19.33%, 18.18%, 46.54%, and 81.01%, respectively.(2) Humic acid could improve the root morphology of maize roots by increasing root length, root number, root volume, root surface area, and average diameter of the maize roots. Compared with the control, the average value of the total root length, total root number, root volume, root surface area and average diameter of maize with humic acid treatment increased by 13.51%, 16.74%, 69.62%, 14.68%, and 49.28%, respectively.(3) The addition of humic acid increased the number of axial roots, length of axial roots and number of lateral roots in maize roots. The average value above of maize roots with the addition of humic acids increased by 16.28%, 21.65% and 16.80%, respectively, compared with the control treatments.(4) The promoting effect of humic acid on the growth of maize roots showed the tread of first increase and then decrease with the increasing additive amount of humic acid. When the medium concentration was 10 mg C/L, the promotion effect on maize roots was the most significant. Compared with the control, the root dry weight and root activity of maize roots increased by 69.36% and 69.07%, respectively.(5) The addition of humic acids(10 mg C·L-1) could increase the content of carbohydrates, lipids, proteins, peptides, amino acids, and nucleic acids in maize roots. 【Conclusion】The addition of humic acid could significantly increase the biomass, root activity and root-shoot ratio of maize. In addition, it could also improve the root architecture of the maize and the content of main chemical components in maize roots. The medium concentration(10 mg C·L-1) of humic acid had the most significant effect on the promotion of maize roots.