黄枝油杉种苗质量分级标准研究

黄枝油杉由于其分布区狭窄，繁殖速度慢，资源少，是国家二级保护植物。为了更好地保护其种质资源，通过实验研究种苗质量分级标准。分别对2年生和4年生的黄枝油杉种苗性状特征描述，以地径和株高作为主要分级标准代表，运用Excel 2003和SPSS 26.0对种苗特征数据进行统计学相关分析、主成分分析、K均值聚类分析，将其种苗分别2年生和4年生分别分成了三级。2年生一级株高＞20 cm，冠幅＞11 cm，地径≥0.10 cm；4年生一级株高＞127 cm，冠幅＞56 cm，地径≥0.80 cm。2年生二级株高14~20 cm，冠幅8~11 cm，地径≥0.10 cm；4年生二级株高96~127 cm，冠幅38~56 cm，地径≥0.80 cm；2年生三级株高＜14 cm，冠幅＜8 cm，地径≥0.10 cm；4年生三级株高＜96 cm，冠幅＜38 cm，地径≥0.80 cm。

Quality Grading Standard of Seedlings of Keteleeria davidiana var. calcarea (W. C. Cheng & L. K. Fu) Silba

Keteleeria davidiana var. calcarea (W. C. Cheng & L. K. Fu) Silba is a national second level protected plants due to its narrow distribution area, slow reproduction rate and few resources. In order to better conserve the germplasm resources, the quality grading standard of seedlings of Keteleeria davidiana var. calcarea (W. C. Cheng & L. K. Fu) Silba were experimentally studied. The 2-year-old and 4-year-old seedlings with diameter and height as the main grading standard were subjected to statistical correlation analysis, principal component analysis, and K-means cluster analysis using Excel 2003 and SPSS 26.0 to develop a reasonable grading standard for seedlings. The seedlings were divided into three levels at different ages. 2-year-old seedlings: primary plant height was＞20 cm, crown width was＞11 cm, and ground diameter was≥0.10 cm; 4-year old seedlings: primary plant height was＞127 cm, crown width was＞56 cm, and ground diameter was≥0.80 cm. 2-year-old seedlings: secondary plant height was 14-20 cm, crown width was 8-11 cm, and ground diameter was≥0.10 cm; 4-year old seedlings: secondary plant height was 96-127 cm, crown width was 38-56 cm, ground diameter was ≥0.80 cm; 2-year old seedlings: tertiary plant height was＜14 cm, crown width was＜8 cm, ground diameter was≥0.10 cm; 4-year old seedlings: tertiary plant height was＜96 cm, crown width was＜38 cm, ground diameter was≥0.80 cm.