黄腐酸有机肥对盐胁迫下刺槐幼苗生长的影响

Effects of Fulvic Acid Organic Fertilizer on the Growth of Robinia pseudoacacia Seedlings Under Salt Stress

采用盆栽试验,分析盐胁迫下添加黄腐酸有机肥对刺槐1年生幼苗成活率、相对生长速率、最大净光合速率、叶片含水量、生物量分配和根系特征的影响。结果表明:与低盐胁迫相比,高盐胁迫下刺槐幼苗的成活率降低35%,相对生长速率平均降低9.6%,叶生物量比降低7.2%,比根表面积平均降低5.4%,茎生物量比增加3.8%。添加黄腐酸后,随着施肥量的增加,相对生长速率、最大净光合速率和叶片含水量先增加再降低,在4.67 g/盆达到最大值,在低盐胁迫下最大值分别为4.12×10^(-3) mg/(g·d)、11.47μmol/(m^2·s)和69.7%,高盐胁迫下最大值分别为2.21×10^(-3) mg/(g·d)、10.01μmol/(m^2·s)和67.7%;而比根长则逐渐增加。相对生长速率与叶生物量比、最大净光合速率、叶片含水量成显著正相关,与茎生物量比成显著负相关,叶片含水量与最大净光合速率成正相关。因此,添加黄腐酸有机肥通过可以缓解盐胁迫下的生理干旱,通过提高叶片含水量进而增加最大净光合速率和相对生长速率,改善了刺槐幼苗的生长状况。

Through the pot experiment, the effects of fulvic acid organic fertilizer on seedling survival rate,relative growth rate, maximum net photosynthetic rate, leaf water content, biomass distribution and root system of Robinia pseudoacacia were studied under different soil salt stress. The results show that compared with low salt,the survival rate of R. pseudoacacia seedlings decreases by 35%, the relative growth rate decreases by 9.6%, the leaf biomass ratio decreases by 7.2%, the specific root surface area decreases by 5.4%, and the stem biomass ratio increases by 3.8%. With adding fulvic acid and increasing fertilizer levels, the relative growth rate, leaf water content and maximum net photosynthetic rate increase firstly and then decrease, the maximum reaches at 4.67 g/pot,the maximum values under low salt stress are 4.12×10^-3 mg/(g·d), 11.47μmol/(m^2·s) and 69.7%, respectively, and the maximum values under high salt stress are 2.21×10^-3 mg/(g·d), 10.01μmol/(m^2·s) and.67.7%, but specific root length increased gradually. Relative growth rate is significantly positively correlated with leaf biomass ratio, maximum net photosynthetic rate, leaf water content, but significantly negatively correlated with stem biomass ratio.Leaf water content is significantly positively correlated with maximum net photosynthetic rate. Therefore, adding organic fertilizer with fulvic acid can alleviate the physiological drought under salt stress, and improve the growth of R. pseudoacacia seedlings by increasing the leaf water content and increasing the maximum net photosynthetic rate and relative growth rate.