国家自然科学基金和贵州喀斯特科学研究中心 (U1812401)；国家自然科学基金(32260393)；贵州省林业局科研项目(黔林科合［2019］10号)；贵州省科技计划(黔科合支撑［2021］一般224)；贵州师范大学博士科研基金 (GZNUD［2019］18)；贵州省教育厅工程研究中心，喀斯特山地生态安全工程研究中心(黔教合KY字［2021］007)
在全球气候变化背景下，筛选抗旱强的城市绿化花卉植物是应对未来持续干旱下水资源短缺和城市绿化建设的重要途径。该研究以常见的城市绿化花卉植物山茶(Camellia japonica)和西洋杜鹃(Rhododendron hybridum)为材料，利用光学技术构建花瓣和叶片栓塞脆弱性曲线，并观察两种植物的花瓣及叶片形态结构特征，比较两种植物花瓣和叶片组织在水分胁迫期间的抗旱性。结果表明：(1)山茶和西洋杜鹃的生长土壤水势之间在自然干旱下没有显著差异，均从第9天开始与对照相比显著降低；西洋杜鹃叶片和花瓣水势在自然干旱后第9天显著降低，而山茶叶片和花瓣水势在自然干旱持续到第12天时显著降低。(2)西洋杜鹃花瓣和叶片水势的P50值(发生50%栓塞时对应的水势值)分别为-3.24 MPa和-4.40 MPa，分别大于山茶花瓣(-3.99 MPa)和叶片(-5.92 MPa)。(3)山茶和西洋杜鹃间的花瓣厚度、上下表皮厚度没有显著差异，而山茶花瓣的脉密度和气孔密度均显著大于西洋杜鹃花瓣；山茶叶片厚度、上下表皮厚度、海绵组织厚度、叶脉密度均显著大于西洋杜鹃。研究发现，西洋杜鹃的栓塞脆弱性大于山茶，其耐旱性弱于山茶；山茶和西洋杜鹃的栓塞脆弱性与其组织形态结构有关，叶片厚度、上下表皮厚度和海绵组织厚度越大, 栓塞脆弱性越小；在未来干旱程度逐渐加剧的情况下，可以优先选择山茶作为城市绿化的花卉植物。
Under the background of global climate change, screening urban greening plants with strong drought tolerance is an important way to deal with the shortage of groundwater resources and urban greening construction in the future. In this paper, Camellia japonica and Rhododendron hybridum were used as materials, and the drought resistance of petals and leaf tissues of them during water stress were compared. The embolism vulnerability curves of petals and leaves were constructed by optical technology, and the morphological and structural characteristics of petals and leaves in C. japonica and R. hybridum were observed. The results showed that: (1) there was no significant difference in the water potential of the soil where C. japonica and R. hybridum were grown under natural drought, and both were significantly reduced from day 9 compared with the control. The water potential of R. hybridum leaves and petals decreased significantly on day 9 after the natural drought, while the water potential of the leaves and petals of the C. japonica leaves decreased significantly when the natural drought lasted until day 12. (2) The P50 (the corresponding water potential when 50% embolism occurred) values of petals and leaves of R. hybridum were -3.24 MPa and -4.40 MPa, respectively, which were higher than those of C. japonica (-3.99 MPa for petals，and -5.92 MPa for leaves). (3) There was no significant difference in the thickness of petals and the thickness of upper and lower epitheliums between C. japonica and R. hybridum, while the veins density and stomatal density of C. japonica petals were significantly greater than those of R. hybridum; C. japonica leaves thickness, upper and lower epithelium thickness, sponge tissue thickness and leaf veins density were significantly greater than those of the R. hybridum. The embolism vulnerability of C. japonica and R. hybridum is related to its tissue morphological structure, the thicker the leaf thickness, the upper and lower epidermis thickness and the sponge tissue thickness, the less embolism vulnerability there is. In the case of increasing drought in the future, C. japonica can be preferentially selected as a flower plant for urban greening.
夏 英,李婕婷,唐 婧,等.山茶和西洋杜鹃花瓣及叶片的栓塞脆弱性比较[J].西北植物学报,2023,43(1):79-87复制