Effect of phytohormones and elicitors on growth and anthraquinone production of Cassia obtusifolia hairy roots Effects of exogenous 5-aminolevulinic acid on seed germination and physiological characteristics of Cassia obtusifolia seedlings under NaCl stress Effects of exogenous 5-aminolevulinic acid on seed germination and physiological characteristics of Cassia obtusifolia seedlings under NaCl stress Feasibility analysis on the determination of WUE by stable carbon isotope:Cassia obtusifolia L. as an example