Study On Matrix And Water-Nitrogen Management Techniques Of Clerodendrum Inerme In Tropical Reefslsland

Clerodendrum inerme(L.)Gaertn.is one of an important species of mangroves,which has great application value in coastal sand and coral reef greening on account of its good qualities such as salt tolerance,drought tolerance,antibacterial capability.How to improve the survival rate of tree species and reduce the cost of maintenance management are the key problems in the present situation of the severe degradation of the tropical reefsislands and the incomplete vegetation restoration technology.This research embarked from the reef site conditions,complying with the principle of the simplified maintenance steps,lower maintenance cost and prevention secondary pollution,by analyzing the water and nitrogen use efficiency and resistance from the face of the soil,water and nitrogen,in order to master its interaction law and come to the conclusion that the most suitable soil,water and nitrogen combination of growth and development for C.inerme.The specific results are as follows:1.The effect of red soil is the best on the improvement of sandy saline soil.2.The effects of matrix,water,nitrogen and their interactions on chlorophyll,malondialdehyde(MDA),proline(Pro)and relative conductivity of C.inerme were very significant.Under the same water and nitrogen conditions,chlorophyll of the C.inerme in the sea sand matrix was lower and its MDA was higher,and its anti-inversion was worse.In the same substrate,when not applying nitrogen,high frequency irrigation could reduce its chlorophyll,and increase relative electric conductivity,and increases the damage.But when the high-frequency irrigation with high nitrogen,the damage can be alleviated to some extent.The combination of low frequency irrigation and low nitrogen is the most beneficial treatment to enhance the C.inerme resistance and the adaptability to the environment.3.The effects of the C.inerme water utilization efficiency on matrix,water,nitrogen and their interactions were very significant.Due to the limited water retention capacity of sea sand,in the early and middle stages of planting,it is necessary to increase the irrigation frequency to ensure the water absorption and utilization of the C.inerme when the sea sand is the substrate.In the same matrix,in high frequency irrigation,nitrogen plays an important role in improving the water utilization efficiency of the C.inerme,while in low frequency irrigation,it can be counterproductive.4.There was a significant positive correlation between the water use efficiency of the C.inerme and the content of chlorophyll and proline(Pro).And there was a high significant positive correlation between the content of chlorophyll and the content of proline.The accumulation of proline can improve the anti-reversibility of the C.inerme and promote its synthesis of chlorophyll,thus improving its photosynthetic rate and accumulation of organics.5.The C.inerme has a strong adaptability to the original sand matrix of coral reef islands,so on the basis of reasonable conservation,there is no need to improve it.In the first three months after planting,it is advisable to use high frequency irrigation to combine with high nitrogen.When the growth condition of the C.inerme is stable,the management mode of low-frequency irrigation and low nitrogen can be adopted to improve the anti-retrograde and water use efficiency of the C.inerme.