Search Results

You are looking at 1 - 4 of 4 items for

  • Author or Editor: Kai Gao x
Clear All Modify Search

Turnip (Brassica rapa L. subsp. rapa) is a type of root vegetable belonging to the Brassica subspecies of Cruciferae. Salt stress is one of the main abiotic stresses that causes water deficit, ion toxicity, and metabolic imbalance in plants, seriously limiting plant growth and crop yield. Two commercial turnip cultivars, Wenzhoupancai and Qiamagu, were used to evaluate the seed germination and physiological responses of turnip seedlings to salt stress. NaCl was used to simulate salt stress. Parameters of seed germination, seedling growth, osmoregulation substances content, chlorophyll content, antioxidant enzyme activity, and other physiological parameters of turnip seedlings were measured after 7 days of salt stress. The results showed that salt stress reduced the seed germination rate, and that the seeds of ‘Wenzhoupancai’ were more sensitive to salt stress. Salt stress inhibited the growth of turnip seedlings. With the increased NaCl concentration, the seedling dry weight, seedling fresh weight, and seedling length of turnip decreased gradually. Under the salt stress treatment, the osmotic regulatory substances and antioxidant enzyme activity in the seedlings of turnip increased significantly. The chlorophyll content increased at a lower NaCl level, but it decreased when the level of NaCl was higher. Growth parameters of turnip seedlings had significant negative correlations with the reactive oxygen content, osmoregulation substances, and antioxidant enzyme activities, but they had positive correlations with chlorophyll b and total chlorophyll content. These results indicated that salt stress-induced oxidative stress in turnip is mainly counteracted by enzymatic defense systems.

Open Access

Hydrogen sulfide (H2S) was recently recognized as an endogenous gaseous molecule involved in seed germination, root organogenesis, abiotic stress tolerance, guard cell movement, and delay of senescence in plants. In the present study, we show that H2S participates in the regulation of postharvest ripening and senescence in fresh-cut kiwifruit, Actinidia deliciosa. Fumigation of fresh-cut kiwifruit with the H2S donor sodium hydrosulfide (NaHS) solution prolonged kiwifruit storage time and alleviated senescence and tissue softening in a dose-dependent manner at an optimal concentration of 1.0 mmol·L−1 NaHS. H2S treatment maintained higher levels of reducing sugars, soluble proteins, free amino acids, ascorbate, and chlorophyll and lowered carotenoid levels. H2S treatment also significantly decreased the contents of malondialdehyde (MDA), hydrogen peroxide (H2O2) and superoxide anion (O2 ) during fruit storage compared with water controls. Furthermore, the activities of guaiacol peroxidase (POD), catalase (CAT), ascorbate peroxidase (APX), and glutathione reductase (GR) were increased by H2S treatment, whereas the activity of lipoxygenase (LOX) was decreased compared with untreated controls. Taken together, these results suggest that H2S is involved in prolonging postharvest shelf life and plays an antioxidative role in fresh-cut kiwifruit.

Free access