Dragon fruit （Hylocereus undulates） was planted in a large area of karst region in recent years. To understand whether karst drought may impact on its physiological process is important and useful for planning and m...Dragon fruit （Hylocereus undulates） was planted in a large area of karst region in recent years. To understand whether karst drought may impact on its physiological process is important and useful for planning and management of this fruit. In this study, we contrasted with a relative species Hylocereus undatus, and set up experiment to study physiological and biochemical trait and its response to different karst soil water level deficiency, so as to understand the mechanism of H. undulates and H. undatus in adaptation to karst drought condition. The results showed that, trends of physiological and biochemical response to drought was similar between two species. With the intensive of soil water deficiency, such toxin substance as malonaldehyde （MDA） increased, but meanwhile, two protective enzymes superoxide dismutase （SOD） and peroxidases （POD） and osmotic adjustment Proline （Pro） increase as well. Under relative water content （RWC） 〉50% condition, the enzyme can effectively protect the cells from toxin MDA injure, and Pro can also maintain the water needs through osmotic adjustment. However, under RWC 〈 40% condition, protective enzymes were not enough for cleaning MDA. Biomass was largest under RWC=70%-80%, with low root shoot ratio and high aboveground biomass. Biomass significantly decreased under RWC 30%-40%, which decline by 73.28% and 73.56% in H. undulates and H. undatus respectively. Therefore, RWC=70%-80% would be an optimal soil moisture while developing dragon fruit in karst, which is favor to fruit production. Under moderate drought e.g. RWC=50%-60%, plants may regulate by metabolic process and balance unfavorable substance, but it allocated much more biomass to root, reduced the aboveground biomass, which is not advance for fruit production.展开更多
In this paper, responses of germination physiology of pigeon pea （Cajanus cajan） seeds to drought stress in karst water environment and non-karst （allogenic） water environment were studied to explore the adaptabil...In this paper, responses of germination physiology of pigeon pea （Cajanus cajan） seeds to drought stress in karst water environment and non-karst （allogenic） water environment were studied to explore the adaptability of pigeon pea to karst environment. The results showed that： （i） Under drought stress of 20% PEG- 6000, the germination rate, vigor index, germination index and biomass of pigeon pea seeds on day 7 cultivated with karst water were all greater than that of the allogenic water treatment group, while the seed germination stress index was significantly smaller than that of the allogenic water treatment group, suggesting that karst water environment was more favorable to pigeon pea seed germination. （ii） Without drought stress, the malondialdehyde （MDA） and superoxide dismutase （SOD） activities of pigeon pea seeds cultivated with karst water were all smaller than that of the allogenic water group. However, under drought stress, the SOD activity was significantly higher than that of allogenic water group, suggesting pigeon pea SOD in karst water was able to more rapidly respond to external drought stress, and increase its own activity to reduce the damage to the plants. And （iii） with and without drought stress, the soluble protein level of the karst water group was higher than that of the allogenic water group, while the free amino acid level was lower than that of the allogenic water group. This difference was more significant with the presence of drought stress, suggesting that the karst water environment was more favorable to the accumulation of soluble proteins and thus produced larger biomass. Hence, pigeon pea is a tree species that is adapted to high-calcium, alkaline environments in karst areas, and is of great significance for the revegetation and rocky desertification control in mountainous karst areas.展开更多
基金the National Science and Technology Support Program(2012BAC16B01,2012BAC16B02)National Natural Science Foundation of China(41172313)
文摘Dragon fruit （Hylocereus undulates） was planted in a large area of karst region in recent years. To understand whether karst drought may impact on its physiological process is important and useful for planning and management of this fruit. In this study, we contrasted with a relative species Hylocereus undatus, and set up experiment to study physiological and biochemical trait and its response to different karst soil water level deficiency, so as to understand the mechanism of H. undulates and H. undatus in adaptation to karst drought condition. The results showed that, trends of physiological and biochemical response to drought was similar between two species. With the intensive of soil water deficiency, such toxin substance as malonaldehyde （MDA） increased, but meanwhile, two protective enzymes superoxide dismutase （SOD） and peroxidases （POD） and osmotic adjustment Proline （Pro） increase as well. Under relative water content （RWC） 〉50% condition, the enzyme can effectively protect the cells from toxin MDA injure, and Pro can also maintain the water needs through osmotic adjustment. However, under RWC 〈 40% condition, protective enzymes were not enough for cleaning MDA. Biomass was largest under RWC=70%-80%, with low root shoot ratio and high aboveground biomass. Biomass significantly decreased under RWC 30%-40%, which decline by 73.28% and 73.56% in H. undulates and H. undatus respectively. Therefore, RWC=70%-80% would be an optimal soil moisture while developing dragon fruit in karst, which is favor to fruit production. Under moderate drought e.g. RWC=50%-60%, plants may regulate by metabolic process and balance unfavorable substance, but it allocated much more biomass to root, reduced the aboveground biomass, which is not advance for fruit production.
基金National Natural Science Foundation of China(41302289)the Natural Science Foundation of Guangxi(2014GXNSFBA118225)+1 种基金the Project of the China Geological Survey(12120113005300)the Ministry of Land and Resource(201211086-05)
文摘In this paper, responses of germination physiology of pigeon pea （Cajanus cajan） seeds to drought stress in karst water environment and non-karst （allogenic） water environment were studied to explore the adaptability of pigeon pea to karst environment. The results showed that： （i） Under drought stress of 20% PEG- 6000, the germination rate, vigor index, germination index and biomass of pigeon pea seeds on day 7 cultivated with karst water were all greater than that of the allogenic water treatment group, while the seed germination stress index was significantly smaller than that of the allogenic water treatment group, suggesting that karst water environment was more favorable to pigeon pea seed germination. （ii） Without drought stress, the malondialdehyde （MDA） and superoxide dismutase （SOD） activities of pigeon pea seeds cultivated with karst water were all smaller than that of the allogenic water group. However, under drought stress, the SOD activity was significantly higher than that of allogenic water group, suggesting pigeon pea SOD in karst water was able to more rapidly respond to external drought stress, and increase its own activity to reduce the damage to the plants. And （iii） with and without drought stress, the soluble protein level of the karst water group was higher than that of the allogenic water group, while the free amino acid level was lower than that of the allogenic water group. This difference was more significant with the presence of drought stress, suggesting that the karst water environment was more favorable to the accumulation of soluble proteins and thus produced larger biomass. Hence, pigeon pea is a tree species that is adapted to high-calcium, alkaline environments in karst areas, and is of great significance for the revegetation and rocky desertification control in mountainous karst areas.
