Breeding And Mixed Planting Of Local Tree Species Calophyllum Inophyllum And Scaevola Sericea In Coastal Shelterbelt On Hainan Island

In order to take full advantage of the local tree species Calophyllum inophyllum L. and Scaevola sericea Vahl. for ecological protection of the coast on Hainan Island, the resource distribution of C. inophyllum and S. sericea were investigated. It was studied the the seed phenotypic traits and germination of C. inophyllum from different provenances and the cuttage breeding of S. sericea from different provenances. The seedlings of C. inophyllum and S. sericea were planted in the coastal shelterbelt of Casuarina equisetifolia L., and the growth of seedlings and the environmental factors were monitored. It was analyzed the relationships between the growth of seedlings and the environment factors and it was discussed the application potential of the local tree species in construction of coastal shelterbelt.(1) The resource and distribution of C. inophyllum and S. sericea were systematically investigated. One investigation site was set in almost every coastal town in 12 coastal cities or counties on Hainan island where there was vegetation distribution and transportation was available. The sites were with the length about 500 m along the coastline and the width about100 m. The result showed that there were 14 sites of coastal towns with the distribution of C.inophyllum and 12 sites with S. sericea. The C. inophyllum and S. sericea were extensively distributed on the eastern coastal region of Hainan island.(2) The seed phenotypic traits and germination of C. inophyllum were significantly different among the three provenances of Haikou, Wenchang and Qionghai. The length, the width and the thickness of the seeds and the fruit pits, and the air-dry weight of fruit pits among the provenances were in the order of Haikou > Wenchang > Qionghai. The highest germination rate, germination potential, germination index and height of the seedlings of 2months occurred in the seeds from Wenchang. There were positive significant correlation between the rate, the potential and the index of germination and the air-dry weight, the length,the width and the thickness of fruit pits. The seeds with the treatment of 100 mg/L GA3 had the highest germination rate, germination potential and germination index. Appropriate concentration of plant growth regulator could promote the seeds germination.In the cuttage breeding of S. sericea from Chengmai, Wenchang and Sanya, the cuttings were treated with different soil and different concentrations of GA3. The result indicated that the 3 different factors, i.e. provenances, soil types and GA3 concentrations and the interaction of the 3 factors all had significant effects on the survival rate of cutting of S. Sericea. It was in the order of provenance > soil > concentrations of GA3. The survival rate of cuttings fromWenchang was significantly higher than that from Chengmai and that from Sanya. The survival rate of the cuttings in loam were significantly higher than that in sandy soil and that in mixed soil(loam : sandy = 1:1), and that in mixing soil was significantly higher than that in sandy soil. The treatment with 100 mg/L GA3 had highest survival rate, but there were no significant difference among three different concentrations of GA3. The optimum conditions for the cuttings of S. Sericea with the greatest survival rate is cuttings from Wenchang +mixed soil(loam : sandy = 1:1) + 100 mg/L GA3.(3) The survival rate of seedlings of C. inophyllum and S. sericea mixed planting in the C. equisetifolia shelterbelt declined and the height and the basal diameter increased with the time in the duration from April in 2013 to April in 2014.The diurnal change of the photosynthesis of C. inophyllum and S. sericea had the features as follows. The curves of net photosynthetic rate of the 2 species were with one peak,while the peak of C. inophyllum appeared in 12:00-14:00 and S. sericea appeared in10:00-12:00. The stomatal conductance of C. inophyllum was relatively stable and that of S.sericea decreased continuously in daytime. The curves of intercellular CO2 concentration was in V shape with one valley in C. inophyllum and W shape with 2 valleys in S. sericea. The maximum transpiration rates appeared in the period of 14:00-16:00 in C. inophyllum and in10:00-12:00 in S. sericea.The seasonal change of the photosynthesis of 2 species was as follows. In the duration from July in 2013 to April in 2014, the net photosynthetic rate, stomatal conductance,transpiration rate in July 2013 and April 2014 were higher than those in other times and the lowest values appeared in January 2014. The highest intercellular CO2 concentration appeared in January 2014. The net photosynthetic rate, stomatal conductance, transpiration rate in July and October in 2014 were higher than those in the same season of last year.The net photosynthetic rates and transpiration rates of the 2 species were significantly positively related to the light intensity under forest and the soil temperature. The net growth of height and basal diameter of S. sericea were significantly positively related to the light intensity under forest and the soil temperature, and significantly negatively related to the soil salt content.