文冠果柿树花椒幼树对不同土壤水分的生理响应

Physiological responses to different soil water contents in Xanthoceras sorbifolia Bunge.,Diospyros kaki Linn. and Zanthoxylum bungeanum Maxim. seedlings

为探索文冠果、柿树、花椒在不同土壤水分含量下的生理特性,利用盆栽试验人工浇水后持续自然耗水的方法,研究2年生文冠果、柿树、花椒在不同土壤相对含水量（15%~98%）下的生理响应,并结合大田栽植的生长状况和成活率对其抗旱性进行评价。结果表明：1）随土壤相对含水量的降低,文冠果、柿树、花椒幼树叶片的相对含水量都呈下降趋势,净光合速率、水分利用效率先升高后降低,脯氨酸质量分数、细胞膜相对透性逐渐上升,叶绿素逐渐降低,超氧化物歧化酶活性先升高后降低,丙二醛质量摩尔浓度先升高后降低再升高;2）文冠果、柿树、花椒幼树光合作用由气孔限制转为非气孔限制的土壤相对含水量分别为60%~70%、30%~40%、20%~30%;3）花椒在土壤相对含水量为20%~70%时耐旱能力较强,柿树在土壤相对含水量为20%以下时耐旱能力更强,文冠果耐旱能力较差。结合大田生长表现可知,在山东丘陵区造林时花椒较为适宜。

Water deficit is one of the major factors limiting plants grown on the hills in Shandong Province. Xanthoceras sorbifolia Bunge.,Diospyros kaki Linn. and Zanthoxylum bungeanum Maxim. are common afforestation tree species in Shandong. The mechanisms of the physiological change of these tree species in different drought regimes and their drought resistance remain unclear. Through pot and field experiments,we evaluated the drought-resistant ability of the above three tree species by investigating the process and mechanism of their physiological changes in response to drought stress. The physiological responses of two-year-old X. sorbifolia,D. kaki and Z. bungeanum seedlings to soil drought stress were examined by natural drought method in pot experiments. The results showed that： 1） With the relative soil water content（ Wr） reducing,the relative leaf water content and the chlorophyll content decreased gradually,the proline content and relative permeability of cell membrane increased,net photosynthetic rate（ Pn）,water use efficiency and superoxide dismutase activity increased initially and then decreased,malondialdehyde content increased firstly and then decreased and ascended again; 2） When the soil water content was 60%- 70%,30%- 40% and 20%- 30%,the stomatal limitation of Pnchanged into non-stomatal limitation in X. sorbifolia,D. kaki and Z. bungeanum seedlings,respectively. In general,drought-resistant capability of Z. bungeanum is the strongest under moderate water stress,D. kaki is thebest under severe water stress,and X. sorbifolia is the poorest under all experimental conditions.Combining the field growth performance,it is suggested that Z. bungeanum be an optimum species for afforestation in hilly regions of Shandong Province.