The effects of humic acid on growth and ion uptake of mung bean (Vigna radiata (L.) Wilczek) grown under salt stress

摘要

The study aimed to determine the effects of humic acid (HA) on seedlings of a salt-sensitive plant, mung bean (Vigna radiata (L.) Wilczek), grown on 50 mM (S1) and 100 mM (S2) NaCl concentrations. In controlled room conditions, mung bean seedlings were planted in pots containing torf and perlite mixture and salt effects were observed. The growth parameters were plant height, number of leaves, leaf area, leaf and stem fresh and dry weights in which all parameters significantly decreased at both salt levels. Nutrient analyses of Na, K and Ca were conducted by flame photometry (FP), and Mg, Mn, Zn were tested by inductively coupled plasma atomic emission spectrometry (ICP-AES), for the above and below ground parts of mung bean seedlings. Both salt treatments increased Na content significantly, however 10 ml addition of HA to those samples (S1HA and S2HA; 50 mM NaCl and 100 mM NaCl, respectively) caused reductions in Na contents of the above-ground parts of mung bean compared to plants watered with only Hoagland-Arnon solutions (HO). On the other hand, in the roots of mung bean seedlings, Na content rose significantly in S2 compared with control, but the amount of Na in S2HA significantly increased compared with S2 treated plants. K content was significantly decreased in both salt concentrations, while SHA1 and SHA2 caused slight increases in both above and underground parts of seedlings. In the experiment, SHA2 increased the content of K, Mg, Ca, Mn and Zn in the root of mung bean seedlings compared with both S1 and S2 treatments.