| Sapium sebiferum (Linn.) Roxb. belongs to Sapium Jacq. of Euphorbiaceae, it is deciduous trees with significant values in Landscaping and provdign industry oil.. The seed enriches with pill oil and stillingiaoil, which was an ideal substitution of cocoa butter and biodiesel feedstocks respectively. In this paper, aimed at selecting plus germplasm of high efficient photosynthesis and strong resistance to drought,1year seedlings growing from seeds harvested from6different plus trees located at Sanzi county, Dao county of Hunan province, Nanjing city of Jiangsu province and Shaoguang of Guangdong province were treated with PEG6000simulated drought stress and drought stress naturally, and then investigation and analysis on traits of photosynthesis and drought-resistatant among them were conducted. Meanwhile, correlation among seeds quality and growth vigor, photosynthesis capacity, resistant to drought stress was analyzed,so as to get references for selecting good germplasm of Sapium sebiferum The results showed as followings:(1) Elite Sapium sebiferum had great differences among fruits, seeds and oil, which could be used as important parameters in the future work. The seed characteristics showed that Sangzhi12was heavier than others, Shaoguan23and24had more total oil than others and Nanjing13was more stable than Sangzhi and Shaoguan elite strains. And those would be the indexes for selecting plus germplasm of elite Sapium sebiferum(2)Seed quality and oil quality showed that the total oil (skin oil+azusa oil) negatively related to the seed weight after remowing waxy. The same relationship between C18:0and C18:l; but the total oil content positively related to C18:0.(3)Plant height and basal diameter showed that elite Sapium sebiferum offspring seedlings gained the maximum growth in July and differentiated mostly in August. Therefore, it is important to study the physiological characteristics of Sapium seedlings in July and August. Diurnal variation of height and basal diameter indicated that#13Sapium had the largest growth rate in August compared to July, while the#24Sapium was just another way around. There was significant positive correlation between height and basal diameter.(4)The net photosynthetic rate of six elite Sapium sebiferum one year old seedlings was double-peak and existed significant photosynthesis "noon-rest" on sunny day. According to the net photosynthetic rate, transpiration rate and water use efficiency, we could conclude that we should choose the#26and#24Sapium seedlings, which were common photosynthetic rate, low consumption of water and high water use efficiency, to plant in arid region. While in the place with enough water, we should choose the#21and#23Sapium seedlings, which were high photosynthetic rate.(5)Physiological and biochemical indexes of PEG6000simulated drought indicated that#13and#24Sapium had a better drought tolerance;#23Sapium is the least. In the term of natural drought,#13Sapium had the strongest drought tolerance, then#24,the worst one is#23.The results of two kinds of drought stress were basically the same. So, in the future work, we can choose the method of PEG6000simulated drought instead of natural drought.(6)We detected the relationship between seed traits and growth, photosynthesis and stress resistance of offspring seeding. There was significant positive correlation between visible characteristics of the seeds and seedling growth in June, negative correlation between oil quality and seedling growth in June. There was a significant positive correlation between catalpa oil content of the seed and water use efficiency of the seedling. So does the visible characteristics of the seed and seedling's water content, the height of seedling and photosynthetic rate and transpiration rate. Therefore, in the future of Sapium sebiferum planting, we should choose high Azusa oil content, full shape seeds and high height seedlings. |
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