广东亚热带森林木本植物幼苗生长特性研究

研究了广东亚热带42种木本植物幼苗的生长及其与物种的生态特性、生活型、种子大小的相互关系.较强光下(H,66.8μmol m-2s-1)乔木幼苗的茎高和茎生物量显著高于灌木幼苗的相应值,但在较低光下(L,33.7μmol m-2s-1)两者无显著差异.而阳性植物、耐阴植物和中间型植物之间,茎高和茎生物量无显著差别.乔木幼苗的叶面积和叶生物量比灌木幼苗大,但灌木幼苗的叶片数较乔木幼苗多.大种子种和小种子种幼苗之间,阳性植物、耐阴植物和中间型植物幼苗之间的叶片数和叶面积一般无显著差异.阳性植物幼苗比耐阴植物幼苗侧根数多.乔木幼苗的根生物量和根/茎比显著高于灌木幼苗在较高光下,阳性植物幼苗的根/茎比较耐阴植物幼苗高,但在较低光下无明显差异.45d幼苗的根生物量与种子重量呈显著的正相关,而90 d幼苗无明显的相关.乔木幼苗个体生物量显著高于灌木幼苗.幼苗相对生长率和叶面积比的大小呈现如下顺序阳性植物＞中间型植物＞耐阴植物,但只有阳性植物和耐阴植物之间有显著差异.阳性植物、中间型植物和耐阴植物幼苗之间的单位叶率无显著差异.

Characteristics of the Seedling Growth of Woody Plants in the Subtropical Forests in Guangdong Province

Seedling growth of 42 woody species of subtropical forests in Guangdong Province was studied in relation to their ecological characteristics, growth forms and seed weight. Seedlings of tree species had significantly higher stem and greater stem biomass than those of shrub species under high light (H, 66.8 μmol m-2s-1), but not low light intensity (L, 33.7 μmol m-2s-1). There was no significant difference among heliophilic species, shade-tolerant species and intermediate light-demanding species in stem height and stem biomass. Tree seedlings had more leaf area and leaf biomass per plant than shrub seedlings, but the latter had more leaves. Difference in leaf number and leaf area was generally not obvious between large-seeded and small-seeded species, and between different types of species based on light demand. Seedlings of heliophilic species had more lateral roots than those of shade-tolerant species. Seedlings of tree species had significantly greater root biomass and higher root/shoot ratio ofbiomass than those of shrub species. Seedlings of heliophilic species had also higher root/shoot ratio than those of shade-tolerant species under H as compared with L condition. Root biomass was significantly positively correlated with seed weight for 45 d seedlings in both H and L light, but not for 90 d seedlings. Very significant linear correlation between seedling biomass and seed weight was found for 45 d seedlings under both H and L light conditions, but not significant for 90 d seedlings under H light condition. Tree seedlings had significantly greater biomass per plant than shrub seedlings. Relative growth rate and leaf area ratio of seedlings were found to be in order of heliophilic species ＞ intermediate light-demanding species ＞ shade-tolerant species, and there were significant difference between heliophilic species and shade-tolerant species. Difference in unit leaf rate was not significant among species of various light-demanding types.