西南桦与光皮桦幼苗叶片表型特征研究

西南桦和光皮桦幼苗外形特征十分相似，在种源不明确的情况下，苗木调运时很难在现场快速鉴别与区分。由于两个树种各自适宜栽培的海拔和气候条件不尽相同，为避免混淆造成不良影响，对两个树种的幼苗叶片表型特征进行调查对比研究。结果表明，光皮桦与西南桦幼苗的叶柄区别显著，前者明显长于后者；光皮桦与西南桦幼苗叶片长宽比区别显著，前者长宽比小，叶形团圆，后者长宽比大，叶形细长；西南桦与光皮桦幼苗叶片基尖比无明显差别。幼苗叶片表型特征的差异性可作为现场快速鉴别区分西南桦与光皮桦幼苗的依据。

Phenotypic Characteristics of Seedling Leaves of Betula alnoides and Betula luminifera

The appearance characteristics of the seedlings of Betula alnoides and Betula luminifera are very similar, which are difficult to be quickly identified and distinguished in the field when the provenance is not clear.The altitude and climate conditions suitable for cultivation of the two tree species are different, in order to avoid adverse effects caused by confusion, the phenotypic characteristics of seedling leaves of the two tree species were investigated and compared.The results showed that the petioles of seedlings were significantly different, the petiole of Betula luminifera was significantly longer than Betula alnoides; the ratio of length to width of leaves was significantly different,Betula luminifera had a small ratio of length to width and a rounded leaf shape, while Betula alnoides had a large ratio of length to width and a slender leaf shape; there was no significant difference in ratio of leaves base and leaves apex.The difference of phenotypic characteristics of seedling leaves can be used as a basis for rapid identification of Betula alnoides and Betula luminifera seedlings in the field.