Abstract:

This study investigated the adaptive responses of Crataegus songarica K. Koch to varying altitudes (1100-1700 m) in Guozigou, Yili, Xinjiang, China, focusing on leaf functional traits and anatomical structure. Results showed that: (1) An increase in altitude led to a reduction in leaf length, leaf width, leaf area, specific leaf area, and chlorophyll content, but an increase in the leaf length to width ratio, specific leaf weight, and leaf dry matter content, with specific leaf weight showing the strongest plasticity. (2) Higher altitudes were associated with increasing leaf thickness, palisade tissue thickness, and upper and lower epidermis thickness, but decreasing central vein thickness and protrusion, with central vein protrusion showing the strongest plasticity. (3) Leaf area was positively correlated with leaf length, length-width ratio, and specific leaf area, while leaf thickness was positively correlated with upper and lower epidermis thickness and central vein protrusion. Overall, our findings indicated that Crataegus songarica adapts to high-altitude conditions by enhancing leaf thickness and dry matter content for better stress tolerance and by diminishing leaf area and chlorophyll content to mitigate leaf damage from intense sunlight. Conversely, at lower altitudes, the plant increases leaf area and chlorophyll content to facilitate organic matter accumulation.

摘要：

为揭示准噶尔山楂（Crataegus songarica K. Koch）对海拔高度变化的响应，以新疆伊犁果子沟不同海拔（1100~1700 m）的准噶尔山楂作为研究对象，分析其叶片功能性状及解剖结构差异。结果显示：（1）随着海拔的升高，准噶尔山楂的叶长、叶宽、叶面积、比叶面积、叶绿素含量呈降低趋势，叶长宽比、比叶重、叶干物质含量呈上升趋势，比叶重可塑性最强。（2）随着海拔升高，叶厚、栅栏组织厚度、上下表皮厚度呈上升趋势；主脉厚度、突起度呈下降趋势，主脉突起度可塑性最强。（3）叶面积与叶长、叶长宽比、比叶面积呈正相关；叶厚与上下表皮厚度、主脉突起度等呈正相关。研究结果表明，准噶尔山楂在高海拔区域主要通过增加叶厚和叶干物质含量以提高抗逆性，减少叶面积、叶绿素含量来降低高光强对叶片的伤害；在低海拔区域主要通过增加叶面积、叶绿素含量来促进有机物的积累。