[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.

Pollination effects on antioxidant content of Perilla frutescens seeds analysed by NMR spectroscopy.

The effects of Perilla frutescens pollination on the content of seed antioxidants were analysed by agronomical and pollination trials, comparing seeds produced from bagged plants in 2013 (A) to prevent access to pollinating insects, and seeds from open-pollinated plants in 2013 (B) and 2015 (C). The seeds of open-pollinated plants were significantly more numerous and heavier than those of self-pollinated plants. 1H NMR seed analysis showed a higher presence of phenolic compounds in open-pollinated seeds, mainly rosmarinic acid and flavonoids, apigenin and luteolin. Flavonoids were present in the glucosylated form in seeds (A) and (C), and in the aglycone form in seeds from (B) plants. Saturated and unsaturated fatty acids (palmitic, linoleic and linolenic) were more abundant in seeds from self-pollinated flowers. Pollination performed almost exclusively by the honeybee notably increased the antioxidant content in perilla seeds and gave rise to a reduction in the fatty acid content.

The influence of meteorological factors on growth and vegetation process of Perilla frutescens (L.) Britton in Lithuania.

The results of a study on the dependence of growth and vegetation process of Perilla frutescens (L.) Britton upon meteorological factors are presented in the article. The investigations were conducted at Kaunas Botanical Garden of Vytautas Magnus University during vegetation periods in 2001-2005. The object of investigations was Perilla frutescens (L.) Britton, a medicinal annual herbaceous plant of Lamiaceae Lindl. family, native of Eastern Asia, which passes the whole development cycle under climatic conditions of Central Lithuania. The duration of vegetation period of Perilla frutescens on the average is 167 days. The earliest beginning of vegetation and optimal climatic conditions for growth are when hydrothermic coefficient reaches 1.60-1.80 (conditions of excessive humidity). Optimal climatic conditions for massive flowering and seed maturation are observed when hydrothermic coefficient decreases to 1.20 - then massive flowering starts 10 days earlier and lasts 25 days longer. A strong correlation was found between massive flowering and hydrothermic coefficient (r(2)=0.9408). Using mathematical-statistical methods, the consistent patterns of growth and vegetation process of Perilla frutescens (L.) Britton were determined, specifying the time for raw material preparation what determines its quality and quantity.

A possible role of an anthocyanin filter in low-intensity light stress-induced flowering in Perilla frutescens var. crispa.

The red-leaved form of Perilla frutescens var. crispa was induced to flower by low-intensity light stress. The leaves of this form are normally red, but turned green under low-intensity light due to anthocyanin depletion in the epidermis. Flowering did not occur when plants were grown under light passed through a red-colored cellophane paper, which has an absorption spectrum similar to that of anthocyanins. High-concentration anthocyanins may play the role of a red-colored optical filter under normal light conditions, and this filter effect may be lost under low-intensity light, causing a change in the wavelength characteristics of the light with which the mesophyll cells are irradiated. This change may induce a photobiological effect leading to flowering. The gene expression and enzyme activity of phenylalanine ammonia-lyase (PAL), the key enzyme for anthocyanin biosynthesis, decreased under low-intensity light. L-2-aminooxy-3-phenylpropionic acid (AOPP), which is widely used as a PAL inhibitor, inhibited low-intensity light stress-induced flowering and increased PAL activity and anthocyanin content. The inhibition of flowering by AOPP in P. frutescens may be through different mechanisms than PAL inhibition.

Perilla frutescens: interesting new medicinal and melliferous plant in Italy.

The goal of this study is to inform those potentially interested (researchers, farmers, industry and public bodies) in the medicinal and aromatic properties, and profitability of Perilla frutescens (L.) Britton (Lamiaceae). Perilla, a medicinal and edible plant of Asian origin, was recently introduced to the Piedmont Region in the north-west of Italy. P. frutescens is commonly known for its anti-allergic, anti-tumor, and anti-oxidant properties. It is also widely used as human food. We collected a variety of data on Perilla crops in the Piedmont Region, including: agricultural practices, crop profitability, and its value as a bee plant. Our results suggest that ease of cultivation, approximate break-even economics, medicinal claims, and value for bees all contribute to make Perilla of economic interest in Italy.

Stress-induced flowering.

Many plant species can be induced to flower by responding to stress factors. The short-day plants Pharbitis nil and Perilla frutescens var. crispa flower under long days in response to the stress of poor nutrition or low-intensity light. Grafting experiments using two varieties of P. nil revealed that a transmissible flowering stimulus is involved in stress-induced flowering. The P. nil and P. frutescens plants that were induced to flower by stress reached anthesis, fruited and produced seeds. These seeds germinated, and the progeny of the stressed plants developed normally. Phenylalanine ammonia-lyase inhibitors inhibited this stress-induced flowering, and the inhibition was overcome by salicylic acid (SA), suggesting that there is an involvement of SA in stress-induced flowering. PnFT2, a P. nil ortholog of the flowering gene FLOWERING LOCUS T (FT) of Arabidopsis thaliana, was expressed when the P. nil plants were induced to flower under poor-nutrition stress conditions, but expression of PnFT1, another ortholog of FT, was not induced, suggesting that PnFT2 is involved in stress-induced flowering.

Epigenetic regulation of photoperiodic flowering.

The cytidine analogue 5-azacytidine, which causes DNA demethylation, induced flowering in the non-vernalization-requiring plants Perilla frutescens var. crispa, Silene armeria and Pharbitis nil (synonym Ipomoea nil) under non-inductive photoperiodic conditions, suggesting that the expression of photoperiodic flowering-related genes is regulated epigenetically by DNA methylation. The flowering state induced by DNA demethylation was not heritable. Changes in the genome-wide methylation state were examined by methylation-sensitive amplified fragment length polymorphism analysis. This analysis indicated that the DNA methylation state was altered by the photoperiodic condition. DNA demethylation also induced dwarfism, and the induced dwarfism of P. frutescens was heritable.