| The Southern red soil region is the second largest water and soil erosion region in China,which involves a wide range of areas,it has great,intensity and deep degree erosion,threatens the environmental problems of the vast areas of Southern China and hinders the social and economic development.Therefore,ecological restoration and reconstruction as well as soil and water conservation work are urgently needed in the red soil region of Southern China.As a good soil and water conservation plant,Dicranopteris dichotoma has a strong function of ecological restoration and soil conservation.However,there are some limiting factors in the field environment to limit its growth and spread in areas with strong soil erosion.In order to promote the further development of ecological recovery and reconstruction and soil and water conservation control in the red soil area of Southern China,it is of both scientific and practical significance to study the stress factors restricting the growth of Dicranopteris dichotoma and analyze its resistance to the stress.In this study,the Zhuxi watershed in hetian town,Changting county,Fujian province was taken as the research area,and the soil and water conservation plant Dicranopteris dichotoma was taken as the research object to study the soil factors limiting the growth of it,the response of it to stress from the soil factors,and the effects of plant growth regulator mepiperonium on the resistance physiology of it.The main conclusions are as follows:（1）The main factors restricting the growth of Dicranopteris dichotoma were analyzed through field sampling and laboratory analysis.（1）Soil factors at different slope positions of microtopography show certain variation rules,and such differences will bring different effects on Dicranopteris dichotoma,so it was possible to discuss the growth limiting factors of Dicranopteris dichotoma with the background of microtopography.（2）Among the soil factors,5 cm underground humidity,5 cm underground temperature,soil N concentration,available nitrogen concentration and soil N/P were important factors affecting the functional characteristics of Dicranopteris dichotoma.In this study,it was found that 5 cm underground humidity was most closely related to the functional traits of Dicranopteris dichotoma.（2）Drought stress was simulated by Polyethylene glycol 6000（PEG 6000）to analyze the drought resistance mechanism of Dicranopteris dichotoma responsing to drought stress.The results were as follows.（1）The Relative electrolytic conductivity（REC）and Malondialdehyde（MDA）contents rose rapidly after stress.However,Dicranopteris dichotoma responded quickly and controlled drought stress immediately,reduced damage to it,and showed strong drought resistance.（2）With the simulated drought stress of PEG 6000,the Superoxide dismutase（SOD）and Catalase（CAT）in the leaves of Dicranopteris dichotoma basically maintained high activity,and were the main antioxidant enzymes for scavenging Reactive oxygen species（ROS）.Peroxidase（POD）activity was very low,but it has a strong correlation with each index,so the effect of POD enzyme on its drought resistance still uncleard,which needs further research and discussion.（3）The regulation of osmotic potential by Proline（Pro）was the most important mechanism in the response to drought stress.Under the stress of 30%PEG6000,the resistance of Dicranopteris dichotoma was the highest.However,beyond this level,its drought resistance mechanism was gradually destroyed and its drought resistance decreased.（3）To explore the induction of mepiperonium on drought resistance of Dicranopteris dichotoma,we applied different concentrations mepiperonium to the control plot and drought-stressed plots in the wild.The results were as follows.（1）After the application of meperidine,the concentration of N and P of Dicranopteris dichotoma increased with the increase of the meperidine concentration,and the differences between the sample plots were narrowed,and decreased after reaching the maximum at the concentration of 300 mg·L-1.The above results show that mepiperidine could promote the accumulation of nutrients in Dicronopteris dichotoma and 300 mg·L-1of methylpipenium was the most suitable concentration.There was a certain correlation between plant nutrients and stress resistance,so the accumulation of nutrients in Dicranopteris dichotoma improved the drought resistance of it to some extent.（2）Mepipanan changed the morphological characteristics of the leaf of Dicranopteris dichotoma,made it more suitable for water shortage environment,and improved drought resistance.Moreover,300 mg·L-1concentration of meperidine had the best induction effect.（3）The content most closely related to the drought resistance of Dicranopteris dichotoma is Pro content,which indicates that the synthesis and accumulation of Pro is the most effective mechanism for Dicranopteris dichotoma to cope with drought stress.Moreover,under the application of300 mg·L-1mepiperidone,the drought resistance of Dicranopteris dichotoma was the strongest.The main conclusions of this study are as follows:（1）Underground humidity of 5 cm was the most important soil factor restricting the growth of Dicranopteris dichotoma,so the drought stress caused by seasonal drought was the most important factor restricting the growth and spread of the Dicranopteris dichotoma.（2）Dicranopteris dichotoma had a strong drought resistance,among which SOD and CAT were the main antioxidant enzymes for cleaning ROS,which can effectively reduce the damage caused by ROS to Dicranopteris dichotoma.Pro played a role in regulating osmotic potential in Dicranopteris dichotoma’s cells.The accumulation of Pro was the main response of Dicranopteris dichotoma to against drought stress.When the degree of stress was too high,the drought resistance of Dicranopteris dichotoma decreased.（3）The plant growth regulator mepium has a certain inducing ability to drought resistance of Dicranopteris dichotoma.Among them,the 300 mg·L-1concentration mepiperidone solution had the best effect of inducing the drought resistance of Dicranopteris dichotoma. |
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