Effect of exogenous 5-aminolevulinic acid on seed germination and antioxidase activities of Perilla frutescens seedlings under NaCl stress Effect of exogenous 5-aminolevulinic acid on seed germination and antioxidase activities of Perilla frutescens seedlings under NaCl stress Preliminary Studies on the Possible Mechanism Underlying 5-aminolevulinic Acid-induced Stomatal Opening in Apple Leaves Flavonols Induced by 5-aminolevulinic Acid are Involved in Regulation of Stomatal Opening in Apple Leaves Flavonols Induced by 5-aminolevulinic Acid are Involved in Regulation of Stomatal Opening in Apple Leaves Preliminary Studies on the Possible Mechanism Underlying 5-aminolevulinic Acid-induced Stomatal Opening in Apple Leaves