千家寨野生古茶树叶片解剖结构和化学组分计量特征对海拔梯度的适应

Adaptation of leaf anatomical structure and stoichiometric characteristics of wild ancient tea tree to different altitudes in Qianjiazhai

以哀牢山千家寨自然保护区内4个海拔(2050、2200、2350、2500 m)的野生古茶树(大理茶种)为研究对象,对其叶片解剖结构和碳(C)、氮(N)、磷(P)含量及其计量比进行测定,进而探究植物对环境变化的响应与适应。结果表明:随着海拔的升高,野生古茶树叶片厚度、表皮厚度、角质层厚度、栅栏组织厚度、海绵组织厚度、主脉厚度以及叶片C含量等指标呈现出增-降-增的变化趋势,在海拔2200 m达到最大值,表明该海拔环境有利于野生古茶树的光合碳同化,其生长代谢较为旺盛;随着海拔的增高,野生古树茶的叶片结构更为紧凑,且叶片C、N、P的累积增加,以适应高海拔的生长环境;各解剖学指标在海拔梯度上具有较大的可塑性,在不同海拔之间变异程度属于中等;该区域野生古茶树的生长并不受N、P元素的限制;千家寨野生古茶树叶片解剖结构和化学计量特征在不同海拔表现出的这种差异,对垂直梯度小生境变化的适应具有重要作用。

We compared leaf anatomical structure,carbon(C),nitrogen(N)and phosphorus(P)concentration and their stoichiometry of wild ancient tea trees(Camellia talinensis)along an altitudinal gradient(2050,2200,2350,2500 m)of Qianjiazhai Reserve in Ailao Mountain to clarify the response and adaptation of tea trees to environmental changes.The results showed that the thickness of leaf and diverse tissues(epidermis,cuticle,palisade tissue,sponge tissue,main vein)and C concentration showed a uni-modal pattern with rising altitude and peaked at altitude of 2200 m,suggesting that the environment at 2200 m altitude was conducive to the wild ancient tea trees for carbon assimilation,growth,and metabolism.The leaf structure became more compact and the concentrations of C,N and P in leaves showed a trend of increase,which would help tea trees adapt to the environment at high altitude.The anatomical indices showed a medium variation and exhibited high plasticity across the altitudinal gradient.Moreover,the growth of wild ancient tea trees in this region was not limited by N and P availability.The differences in either anatomical structure or stoichiometry of wild ancient tea trees across the altitudinal gradient might play a significant role in adapting to the vertical gradient niche.