Postharvest UV-B radiation increases enzyme activity, polysaccharide and secondary metabolites in honeysuckle (Lonicera japonica Thunb.)

The drought resistance mechanism of Matteuccia struthiopteris (L.) Todar. and Athyrium multidentatum (Doll.) Ching were measured under natural drought exposure. The results showed that the two edible fern species showed stronger resistance in the early stages of drought, mainly expressed as the decrease of relative leaf water content (RLWC), increase of osmotic substances, secondary metabolites such as flavonoids (FC), total phenols (TPC), proantho cyanidins (PCC) content and enzyme activity (superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) and ascorbate peroxidase (APX)). The higher RLWC, FC, TPC, PCC and abscisic acid (ABA) content and lower H2O2 content indicates the stronger non-enzymatic antioxidant system and drought resistance of A. multidentatum. However, the proline (Pro) content changed slowly, and the synthesis of soluble protein (SP), total phenols, proantho cyanidins and ABA, SOD activity of two fern species were inhibited in the late stages of drought stress. This study can provide a scientific basis for the cultivation and utilization of edible fern species under forest in Northeast China.

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Secondary metabolites of tea leaves and their role in protecting against environmental stressors

Horticulture and viticulture ◽

10.31676/0235-2591-2020-4-12-17 ◽

2020 ◽

pp. 12-17

Author(s):

N. B. Platonova ◽

O. G. Belous

Keyword(s):

Amino Acids ◽

Enzyme Activity ◽

Secondary Metabolites ◽

Environmental Stressors ◽

Carotenoid Content ◽

Guaiacol Peroxidase ◽

Tea Leaves ◽

Growing Conditions ◽

Tea Leaf ◽

Increased Activity

The dynamics of a number of secondary metabolites and the activity of guaiacol peroxidase in 3-leaf sprout of tea varieties and forms were studied. In the course of 3-year research we noted the presence of declines and peaks in the activity of the enzyme and the accumulation of flavonoids, carotenoids, caffeine and amino acids associated with the meteorological conditions of each month. It is shown that there is a close inverse relationship between increased enzyme activity, carotenoid content and hydrothermal factors. The most significant correlation was found between the activity of guaiacol peroxidase and carotenoids in a 3-leaf tea flush with precipitation (r = -0.86 and -0.68). At the beginning of vegetation the enzyme activity is low (ranging from 0.363 to 0.607 units/g·s). The decrease in the activity of guaiacol peroxidase in June is due to the biological peculiarities of the tea culture associated with a period of rest, during which the metabolic processes are somewhat slowed down. Increased activity of guaiacol peroxidase is accompanied by rapid synthesis of phenolic compounds, such as flavonoids. We have traced the dynamics of the formation of thearubigins and theaflavins in tea sprout. It is shown that their amount varies depending on the season of collection from 0.075 mg/g (theaflavins) and 1.178 mg/g (thearubigins) to 0.115 mg/g and 1.625 mg/g (theaflavins and thearubigins, respectively) and their dynamics is similar. The content of the routine varies depending on the season of tea leaf collection. The synthesis of caffeine also depends on the growing conditions, the active accumulation of which in experimental plants was observed in July (on average 26.6±1.4 mg/g). The largest amount of amino acids (16 665 mg/g) is synthesized in May, and then their synthesis is halved. Genotypic peculiarities are manifested in the content of secondary metabolites and the activity of guaiacol peroxidase. The revealed patterns are common for all varieties and forms of tea.

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