Responses of glutathione and phytochelatins biosysthesis in a cadmium accumulator of Perilla frutescens (L.) Britt. under cadmium contaminated conditions.

Screening new accumulators of heavy metal and identifying their tolerance, enrichment capacity of heavy metals are currently hot issues in phytoremediation research. A series of hydroponic experiments were conducted to analyze the effects of glutathione and phytochelatins in roots, stems, and leaves of Perilla frutescens under cadmium stress. The results showed that the non-protein thiols in roots and stems mainly existed in the form of GSH, PC2, PC3, and PC4 under Cd stress condition, while in leaves they existed in the form of GSH, PC2, and PC3. Furthermore, the contents of GSH and PCs positively correlated with Cd, but negatively correlated with root vigor and chlorophyll content under Cd stress conditions. After 21 days of treatments, the contents of Cd in different parts of the plant were 1465.2-3092.9 mg· kg-1 in the roots, 199.6-478.4 mg·kg-1 in the stems and 61.3-96.9 mg· kg-1 in the leaves at 2, 5, 10 mg·L-1 Cd levels respectively, and the amount of Cd uptakes were up to 3547.7-5701.7 µg·plant-1. Therefore, P. frutescens performed high capacity in Cd accumulation, and PCs played a key role in Cd tolerance. The application prospect of the plant in phytoremediation Cd polluted soil was also discussed.

[Effect of exogenous nitric oxide donor SNP on seed germination and antioxidase activities of Perilla frutescens seedlings under NaCl stress].

OBJECTIVE: To explore the method of improving the salt resistance ability of seeds and seedlings of Perilla frutescens under NaCl stress. METHODS: Physiological indexes of Perilla frutescens seeds treated by sodium nitroprusside (SNP) under NaCl stress like the germination vigor, germination rate, germination index and vigor index were measured. And other indexes like the activities of nitrate reductase (NR), malondialdehyde (MDA), superoxide (SOD), peroxidase (POD) and catalase (CAT) were also measured. RESULTS: The germination indexes of Perilla frutescens seeds under NaCl stress had obvious inhibition. But after the treatment with different concentrations of SNP, every germination indexes were all increased. And the seeds that treated with SNP with the concentration of 0.1 mmol/L has the most significantly increase in every index. The germination vigor was 60.4%, the germination rate was 78.3%, the germination index and vigor index were 13.7 and 0.1093 respectively. The content of MDA was decreased after the treatment of SNP. The activities of four enzymes included NR, SOD, POD and CAT were increased with the treatment of SNP, and get the maximin (1.52 microg/g x h, 0.32 U/mg, 5.9 U/mg and 4.8 U/mg respectively) with the concentration of 0.1 mmol/L SNP. CONCLUSION: SNP with concentration of 0.1 mmol/L could significantly alleviate the damages to the seeds and seedlings of Perilla frutescens under NaCl stress, and promote the salt resistance of the seeds and seedlings.

[Effect of zinc sulphate and PEG priming on ageing seed germination and antioxidase activities of Perilla frutescens seedlings].

OBJECTIVE: To explore the method for improving the aging resistance of seeds and seedlings of Perilla frutescens through study on seed germination and physiological characteristics of P. frutescens seedlings. METHOD: Several physiological indexes of P. frutescens seeds treated by different concentrations of ZnSO4 and PEG were measured. And other indexes like the activities of malondialdehyde (MDA), superoxide (SOD), peroxidase (POD) and catalase (CAT) were also determined. RESULT: The germination indexes of P. frutescens aging seeds treated by different concentrations of ZnSO4 and PEG were all increased. And the seeds that treated by ZnSO4 (600 mg x L(-1)) and PEG (20%) showed the most significantly increase in every index. The germination vigor were 64.7% and 66.8%, the germination rate were 78.7% and 79.4%, the germination index were 11.8 and 12.2, the vigor index were 0.091 1 and 0.0939 respectively. The content of MDA was decreased under different treatment. The activities of three enzymes include SOD, POD and CAT were increased by different treatment of ZnSO4 (0.28, 4.71, 3.82 U x mg(-1) respectively) and PEG (0.29, 4.93, 4.18 U x mg(-1) respectively). CONCLUSION: ZnSO4 with concentration of 600 mg x L(-1) and PEG with concentration of 20% could significantly alleviate the damages to the seeds and seedlings of P. frutescens by aging and promote the aging resistance of the seeds and seedlings.

[Effect of exogenous Ca2+, ALA, SA and Spd on seed germination and physiological characteristics of Perilla frutescens seedlings under NaCl stress].

OBJECTIVE: To find a method for improving the salt resistance of seeds and seedlings for Perilla Frutescens under NaCl stress, seed germination and physiological characteristics of P. frutescens seedlings were studied. METHOD: Several physiological indexes of P. frutescens seeds treated with different concentrations of Ca2+, 5-aminolevulinic acid (ALA), salicylic acid (SA) and spermidine (Spd) under NaCl stress like the germination vigor, germination rate, germination index and vigor index were measured. And other indexes like the biomass of the seedlings, the content of malondialdehyde (MDA) in leaves, the activities of superoxide (SOD), peroxidase (POD) and catalase (CAT) were also measured. RESULT: The germination of P. frutescens seeds under NaCl stress (100 mmol x L(-1)) was inhibited obviously. But after the treatment with Ca2+, ALA , SA and Spd, all germination indexes were increased. Ca2+ (10 mmol x L(-1)), ALA (100 mg x L(-1)), SA (50 mg x L(-1)) and Spd (0.25 mmol x L(-1)) could obviously alleviate the damage of salt stress to the seeds of P. frutescens. ALA (100 mg x L(-1)) significantly increased all indexes. The germination vigor was 65.3%, the germination rate was 89.7%, the germination index and vigor index were 15.2 and 0.1238, respectively. All treatments decreased the content of MDA in leaves. The activities of three enzymes including SOD, POD and CAT were all increased. ALA (100 mg x L(-1)) had the enzymes activity reach the maximum with 0.72, 6, 82 and 5.64 U x mg(-1), respectively. CONCLUSION: Ca2+ ALA , SA and Spd with appropriate concentration could significantly alleviate the damages to the seeds and seedlings of P. frutescens under NaCl stress and promote the salt resistance of the seeds and seedlings.

Metabolomic response of Perilla frutescens leaves, an edible-medicinal herb, to acclimatize magnesium oversupply.

High salt accumulation, resulting from the rampant use of chemical fertilizers in greenhouse cultivation, has deleterious effects on plant growth and crop yield. Herein, we delineated the effects of magnesium (Mg) oversupply on Perilla frutescens leaves, a traditional edible and medicinal herb used in East-Asian countries. Mg oversupply resulted in significantly higher chlorophyll content coupled with lower antioxidant activities and growth, suggesting a direct effect on subtle metabolomes. The relative abundance of bioactive phytochemicals, such as triterpenoids, flavonoids, and cinnamic acids, was lower in the Mg-oversupplied plants than in the control. Correlation analysis between plant phenotypes (plant height, total fresh weight of the shoot, leaf chlorophyll content, and leaf antioxidant content) and the altered metabolomes in P. frutescens leaves suggested an acclimatization mechanism to Mg oversupply. In conclusion, P. frutescens preferentially accumulated compatible solutes, i.e., carbohydrates and amino acids, to cope with higher environmental Mg levels, instead of employing secondary and antioxidative metabolism.