Zheng Yue, Wang Ai-Ying, Su Li-Xin, Guo Jing-Jing, Duan Chun-Yang, Yin Xiao-Han, Gong Xue-Wei, Hao Guang-You
Liaoning Key Laboratory of Urban Pest Management and Biosafety, School of Life Science and Engineering, Shenyang University, Shenyang 110044, China.
Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China.
Ying Yong Sheng Tai Xue Bao. 2022 Mar;33(3):711-719. doi: 10.13287/j.1001-9332.202203.006.
is an important urban ornamental tree species, but poor growth and damages often occur in urban environments. As a street tree species, the decline and death of is particularly frequent, with the relevant physiological mechanism being unclear. In this study, we compared hydraulic characteristics, non-structural carbohydrate (NSC) contents and health status between trees growing along the streets and those in parks in Shenyang City. The results showed that growing along the streets showed higher degrees of branch and leaf mortality than those growing in the parks. Branches of growing in both conditions showed lower degrees of xylem embolism. Branch hydraulic vulnerable curves of under the two growing conditions also showed no significant difference, with the average being lower than -2.8 MPa. growing along the streets had lower leaf area specific conductivity, smaller tracheid diameter, smaller hydraulic diameter, lower soluble sugar content and total NSC than those growing in parks. Hydraulic failure was not the direct reason for the decline and mortality of growing along streets. Under the more stressed growth conditions along the streets, had smaller tracheid diameters in stems and lower Huber values, which limited the ability of water transport and photosynthetic carbon assimilation at the whole branch level. In addition, in order to deal with more serious stress such as greater heat and drought stresses, might need to invest more NSC to repair damage, which further decreaded NSC contents in branches and increased the risk of carbon imbalance. At the same habitat (street or park), xylem hydraulics and NSC contents of also showed relatively large difference among sampling sites, which reflected large heterogeneity of urban environment for tree growth.
是一种重要的城市观赏树种，但在城市环境中常出现生长不良和受损的情况。作为行道树种，其衰退和死亡尤为频繁，相关生理机制尚不清楚。在本研究中，我们比较了沈阳市街道上生长的[树种名称]与公园里生长的[树种名称]的水力特性、非结构性碳水化合物（NSC）含量和健康状况。结果表明，街道上生长的[树种名称]比公园里生长的[树种名称]表现出更高程度的枝叶死亡率。两种生长条件下的[树种名称]枝条木质部栓塞程度均较低。两种生长条件下的[树种名称]枝条水力脆弱曲线也无显著差异，平均[压力值]低于-2.8 MPa。街道上生长的[树种名称]比公园里生长的[树种名称]具有更低的叶面积比导率、更小的管胞直径、更小的水力直径、更低的可溶性糖含量和总NSC。水力失效不是街道上生长的[树种名称]衰退和死亡的直接原因。在街道上压力更大的生长条件下，[树种名称]茎中的管胞直径更小，比叶面积值更低，这限制了整个枝条水平的水分运输和光合碳同化能力。此外，为了应对更严重的胁迫，如更大的热胁迫和干旱胁迫，[树种名称]可能需要投入更多的NSC来修复损伤，这进一步降低了枝条中的NSC含量，增加了碳失衡的风险。在相同的生境（街道或公园）中，[树种名称]的木质部水力和NSC含量在采样点之间也表现出相对较大的差异，这反映了城市树木生长环境的高度异质性。
