不同鲜重秋茄胚轴形态及其对幼苗生长的影响

为了探讨不同鲜重秋茄胚轴的表型性状和营养成分含量差异, 及其对幼苗生长的影响, 确定浙江省秋茄胚轴质量标准, 提高造林质量, 本研究采集4.0~5.0g、5.0~6.0g、6.0~7.0g、7.0~8.0g、8.0~9.0g、9.0~10.0g共6组不同鲜重的秋茄胚轴, 测定其表型性状、营养成分含量和幼苗生长性状。结果表明, 胚轴长度、横径、顶径随着胚轴鲜重的增加而显著增加。不同鲜重等级胚轴间的氮(N)、磷(P)、钾(K)和有机碳百分含量差异不显著, 但随着秋茄胚轴鲜重增加, 淀粉百分含量显著减小。单根胚轴的营养成分总含量随胚轴鲜重的增加而显著增加。胚轴的C:N、N:P和C:P值在鲜重7.0~8.0g等级时均显著高于其他鲜重等级。幼苗生长高、基径、叶片数及生物量随胚轴鲜重的增加而显著增加, 但在5.0~6.0g、6.0~7.0g和7.0~8.0g等级间幼苗茎干重、叶干重、净生物量和总生物量差异不显著。胚轴表型性状与幼苗生长指标之间的相关性均呈显著水平(P<0.05), 除胚轴P总含量与生长高之间的相关性不显著外, N、K、Na、有机碳、淀粉总含量与幼苗生长指标之间均呈显著正相关关系(P<0.05)。主成分分析和综合评价结果表明鲜重7.0g以上的胚轴优于其他鲜重的胚轴。秋茄幼苗生长高和净生物量与胚轴鲜重的回归分析R²分别为0.978和0.951, P均小于0.01。胚轴鲜重大于5.22g时, 幼苗生长高急剧增加; 鲜重大于8.74g时, 幼苗净生物量增长加快。因此, 秋茄胚轴鲜重越大, 营养物质含量越高, 越有利于幼苗生长。在浙江省的秋茄林种植中, 应优先选择鲜重7.0g以上的胚轴。

Morphological characteristics of hypocotyls with different fresh weights of Kandelia obovata and their effects on the seedling growth

In order to explore the phenotypic traits and nutrient contents of different fresh weights of Kandelia obovata hypocotyls and their effects on the growth of seedlings, and to determine the quality standard of hypocotyls in Zhejiang Province and improve the quality of forestation, we collected 6 groups of hypocotyls with different fresh weights (4.0~5.0g, 5.0~6.0g, 6.0~7.0g, 7.0~8.0g, 8.0~9.0g, 9.0~10.0g) to determine their phenotypic traits, nutrient contents and growth characteristics of seedlings. The results showed that the hypocotyl length, transverse diameter, and apical diameter increased significantly with the increase of fresh weight of hypocotyls. The percentage content of nitrogen (N), phosphorus (P), potassium (K), and organic carbon in the hypocotyl were not significantly different among the hypocotyls of different fresh weight, but with the increase of fresh weight of hypocotyls, the percentage content of starch decreased significantly. The total nutrient content in a single hypocotyl increased significantly with the increase of fresh weight of hypocotyls. The values of C:N, N:P and C:P of hypocotyl in fresh weight grade 7.0~8.0 were significantly higher than those in other fresh weight grades. The growth height, basal diameter, leaf number and biomass of seedlings increased significantly with the increase of fresh weight of hypocotyls, but between 5.0~6.0, 6.0~7.0 and 7.0~8.0, the stem biomass, leaf biomass, net biomass and the total biomass of seedlings are not significant. The correlation between hypocotyl phenotypic traits and seedling growth indicators was significant (P < 0.05). Except that the correlation between total P content and growth height was not significant, there was a significant positive correlation between the total N, K, Na, organic carbon, starch content and the growth indicators of seedlings (P < 0.05). The results of principal component analysis and comprehensive evaluation showed that the hypocotyls with fresh weight above 7.0g were better than those of other fresh weights. The regression analysis R² of growth height, net biomass and hypocotyl fresh weight of K. obovata seedlings were 0.978 and 0.951, respectively, with P < 0.01. When the hypocotyl fresh weight was higher than 5.22g, the growth height of seedlings increased sharply. When the hypocotyl fresh weight was higher than 8.74g, the growth of net biomass of seedlings accelerated. The higher the fresh weight of the hypocotyls of K. obovata, the higher the nutrient content, the more conducive to the growth of seedlings. In the planting of K. obovata in Zhejiang Province, hypocotyls with fresh weight above 7.0g should be selected with priority.