辽东栎幼苗生长对种子大小和子叶去除处理的响应

Response of seedling growth of Quercus wutaishanica to seed size and cotyledon excision

关键词:  辽东栎, 种子大小, 子叶去除, 幼苗生长, 形态学可塑性

Key words:  Quercus wutaishanica, seed size, cotyledon excision, seedling growth, morphological plasticity

摘要:

该文在温室内盆播条件下,设置不去除子叶(对照)、去除1/4子叶(轻度子叶去除)、1/2子叶(中度子叶去除)和3/4子叶(重度子叶去除)4个处理,研究了种子大小和子叶去除处理对辽东栎幼苗生长及其形态学可塑性的影响。结果表明:(1)大种子幼苗株高、基茎、叶片数、单株叶面积、总干质量和根冠比在所有处理均大于小种子幼苗,除株高外,上述其他参数在轻度子叶去除处理的不同大小种子幼苗间均差异显著(P<0.05),前者总干质量在中度子叶去除处理与后者差异也显著(P<0.05)。大种子幼苗比叶面积和比根长在各处理均大于小种子幼苗,比枝长则相反。(2)随着子叶去除强度增大,大、小种子幼苗株高、基茎、叶片数、单株叶面积和总干质量等均呈减小趋势,株高、基径、叶片数和单株叶面积在重度子叶去除处理均显著小于对照和轻度子叶去除处理; 小种子幼苗对子叶损失反应更为敏感,其株高、叶片数、单株叶面积和总干质量在中度子叶去除处理也显著小于对照(P<0.05); 小种子幼苗根冠比随子叶去除强度增大而增大,在中度和重度子叶去除处理显著大于对照和轻度子叶去除处理(P<0.05)。(3)随着子叶去除强度增大,大小种子幼苗的比叶面积和比根长均逐渐增大,但大种子幼苗比枝长持续减小,轻度子叶去除处理的小种子幼苗比枝长最大。

Abstract:

Four treatments of cotyledon excisions(no cotyledon excision, excisions of 1/4, 1/2 and 3/4 cotyledon, defined as control, light, medium, and high cotyledon excisions, respectively)were conducted to investigate the effects of seed size and different cotyledon excisions on the growth and morphological plasticity of Quercus wutaishanica seedlings planted in greenhouse pots. The results were as follows:(1)The shoot height(SH), basal stem diameter(BSD), leaf number(LN), leaf area per plant(LAPP), total dry mass(TDM), and root-shoot ratio(RSR)of Q. wutaishanica seedlings germinated from large seeds were higher than those of seedlings from small seeds in all treatments of cotyledon excision. There were significant differences in all above parameters, with the exception of SH, among seedlings from large and small seeds, on which cotyledons were lightly excised(P<0.05). Moreover, TDM of the former was significantly higher than that of the latter for the medium cotyledon excision(P<0.05). Also, higher specific leaf area(SLA)and specific root length(SRL)of seedlings from large seeds than those from small seeds were observed in all treatments of cotyledon excisions, while the specific shoot length(SSL)was detected in reverse.(2)With the intensity of cotyledon excision increasing, SH, BSD, LN, LAPP and TDM of seedlings from both large and small seeds appeared a trend of decline. SH, BSD, LN and LAPP of seedlings emerged from high cotyledon excision seeds were significantly lower than those of seedlings from control and light cotyledon excision seeds(P<0.05). Higher sensitivity to cotyledon excision was found in seedlings from small seeds than from large seeds, and SH, LN, LAPP and TDM of seedlings originated from small seeds, of which cotyledons were mediumly excised were also lower than those of seedlings from control seeds(P<0.05). RSR increased with the intensity of cotyledon excision increasing, and they were markedly higher in seedlings from seeds, regardless of whether they were large or small sized, mediumly and highly excised than those in seedlings from control and light cotyledon excision seeds(P<0.05).(3)With the intensity of cotyledon excision increasing, SLA and SRL gradually increased, while SSL of seedlings emerged from large seeds continuously decreased and the seedlings emerged from small seeds whose cotyledons were lightly excised had the maximum of SSL.