不同种源花楸树幼苗越夏能力的比较

Comparision in thermotolerance over summer of seedlings among different provenances of Sorbus pohuashanensis(Hance)Hedl

以来自6个种源花楸树1年生幼苗为材料,通过观测苗木田间生长表现、叶片相对电导率、光合特性等生理指标并利用隶属函数综合评价不同种源花楸树对夏季高温环境的适应性,为早期筛选出适应低海拔地区的优良种源奠定理论基础。结果表明:不同种源对高温的适应性表现不同。山东崂山种源的苗高年增长量最大,为34.99 cm,而河北雾灵山种源的地径年增长量最大(6.90 mm);河北驼粱山种源的净光合速率和蒸腾速率最高,分别为12.1μmol CO2·m-2·s-1和6.28μmol H2O·m-2·s-1,而山西庞泉沟种源净光合速率和蒸腾速率最低,分别为8.03μmol CO2·m-2·s-1和4.39μmol H2O·m-2·s-1。山西庞泉沟种源叶片受伤害程度最大,叶伤害指数为46.53%;受伤害最小的是山东泰山种源,叶伤害指数为17.75%。综合评价表明,越夏能力最强的是山东泰山和山东崂山种源,河北种源次之,山西种源最差。

As an important tree species with high economic and ecological values, Sorbus pohttas- hanensis （Hance） Hedl. is naturally distributed in the alpine forest ecosystems in North China. Growth traits and physiological parameters in field were measured and heat tolerance of 1-year-old seedlings of six provenances were evaluated by subordinate function in order to select superior provenances at the earlier stage, which could well adapt to the habitats at low altitudes in North China. The results indicated that seedlings of the different provenances showed different adapta- bility to hot summer. Annual height increment of seedlings from Shandong Laoshan was the lar- gest （34.99 cm） , and annual ground diameter increment of seedlings of Hebei Wuling mountain provenance was the largest （6.90 mm）. Net photosynthetic rate and transpiration rate of seed- lings of Hebei Tuoliang moutain provenance were the highest （ 12.1μmolCO2·m^-2·s^-1 and 6.28 μmol H2O·m^-2·s^-1, respectively） , and those of Shanxi Pangquangou provenance were the lowest （8.03μmolCO2·m^-2·s^-1 and 4.39 μmol H2O·m^-2·s^-1, respectively）. Leaf damage of seedlings from Shanxi Pangquangou provenance was the greatest with the leaf damage index of 46.53%, while that from Shandong Taishan provenance was the least with the leaf dam- age index of 17.75%. Comprehensive evaluation results indicated that the 1-year-old seedlings originally coming from Shandong Province （Taishan and Laoshan） adapted better to the condi- tions of hot summer in Beijing Plain than those from other provinces.