The Effects Of Nitrogen And Phosphorus Nutrition On The Growth And Cold Resistance Of Jatropha Curcas L.

Jatropha curcas L. is a specie of Euphorbiaceae family. It mainly grows up in tropical and Subtropical area. Its fruit has high oil content and is very valuable and safe in use after being processed into biodiesel. Besides, its beautiful tree crown and flower make it ornamental. Jatropha curcas L. resists to dry and poor land, and pests, so it is the first choice of species of trees for renewable green energy development. We can see the extensive prospects of usage and development.Although Jatropha curcas L. has been cultivated, but the research on seedlings growth controls via different nutrient proportion has not been reported yet. Jatropha curcas L. mainly grows in the lower latitudes and less cold resistance, therefore the popularization of Jatropha curcas L. cultivation in the higher latitudes are limited. Besides, the south of China often suffers from a sudden cooling weather in recent years, which also raised the new requirements on the improvement of cold resistance for Jatropha curcas L. Focus on the regulate and control of the growth and development and cold resistance issue of Jatropha curcas L., in this study, we investigated the impact of nitrogen and phosphorus coordinate fertilize and chemical reagent spray on the growth of Jatropha curcas L. in the experiment, the results are as follows:1,Using ammonium nitrate and superphosphate as nitrogen and phosphorus sources, combined which in complete random according to high, medium and low concentration and researched on the impact that different nutrient ratio caused on the growth of Jatropha curcas L. seedling. We find out that:Nitrogen is the major factor that effect the height and the ground diameter of Jatropha curcas L. seedling. The ground diameter of seedling under the treatment of N2P3 and N3P3 obviously increases and the height is increased by 23% to the control plant. To the increase of the ground diameter of seedling, the effect of nitrogen is greater than phosphorus. Under the treatment of N2P3 and N3P3, the leaves of seedling are obviously more than the comparison sample. The higher phosphorus concentration can raise the seedling of the seedling accumulating dry matter, but the over-high nitrogen concentration may affect the distribution of carbon and be harmful to the growth of the root. Under the treatment of N2P3, the dry weight is the biggest. It is very different and 90.88% higher than the comparison sample. Under the treatment of N1P1, the dry weight is the smallest. There is no big difference to the control one. Under the treatment of low-nitrogen, the root cap ratio is higher than others. The content of soluble protein of Jatropha curcas L. sprout varies directly with the nitrogenous fertilizer application. Under the treatment of N2P3, the content of solubility sugar increases obviously.2,Further study of nitrogen and phosphorus rate on photosynthetic characteristics and the regulate of chlorophyll synthesis of Jatropha curcas L. seedling was conducted. To fertilize with the combination of nitrogen and phosphorus has very distinguished affection to the photosynthesis and the chlorophyll biosynthesis of the Jatropha curcas L. seedling. Under the treatment of N2P2 and N2P3, compared with the treatment under control, there was obvious rising in the indicator of Pn and Tr and which reached to a significant level. As the fertilizer of phosphorus increasing, the Pn of functional leaves strengthens. Under different fertilizations, the stomata are the main reason of affecting the photosynthesis. In a certain range of fertilization, the content of chlorophyll and the speed of photosynthesis rise obviously. It is considered that under the treatment of N2P3, the growth of the Jatropha curcas L. seedling is much better than others by comparison of the indicators of the ground diameter, height, content of leaf's soluble protein and the photosynthesis.3,The experiment was carried out under natural low temperature conditions, which improve the cold resistance of seedling through spraying different chemical reagent such as NaCl, SA and PP333 etc. and extend its growing season in higher latitudes. Spraying the chemical reagent with different concentration before cold weather coming, can make the activity of POD and SOD and the relative conductivity changed. Spraying 0.1mmol/1 SA and 0.1mmol/1 PP333 before cold weather coming can raise the activity of protective enzyme and the content of soluble protein, and further protect the seeding from cold weather and raise the ability of resisting to the low temperature above freezing.