Promotive effect of 5-aminolevulinic acid on chlorophyll, antioxidative enzymes and photosynthesis of Pakchoi (Brassica campestris ssp. chinensis var. communis Tsen et Lee)

The objective of this article is to study the effect of 5-aminolevulinic acid (ALA) and enhanced chlorophyll content, antioxidative enzymes and photosynthesis rate by foliar application of ALA. We evaluated three concentrations (control-distilled water, T1-50 mg l(-1), T2-150 mg l(-1), T3-250 mg l(-1)) of ALA and seven cultivars, Sanchidaye (Sa-1), Lichuandasuomian (Li-1), Aijiaohuang (Ai-1), Qingyou No. 4 (Qi-1), Aikang No. 5 (Ak-1), Hanxiao (Ha-1) and Shulv (Sl-1). Ak-1 showed strongest response of POD (peroxidase) enzyme activity (0.4 U g(-1) min(-1)) in 250 mg l(-1) ALA solution. The highest CAT (catalase) activity (0.8 U g(-1) min(-1)) after administration of 250 mg l(-1) ALA was observed in Li-1. Meanwhile, highest (1.42 mg l(-1)) total chlorophyll content was also observed in Ak-1, when leaves were treated in 50 mg l(-1) ALA, Li-1 and Ai-1 showed strongest response of specific activity of superoxide dismutase (SOD) in 50 mg l(-1) and 50 mg l(-1) ALA. Two hundred and fifty milligram per milliliter of ALA-treatment significantly improved the net photosynthetic rate.