光照强度对曼陀罗和紫花曼陀罗生长发育的影响

以曼陀罗(Datura stramonium)及其变种紫花曼陀罗(Datura stramonium var. tatual)为研究材料, 采用光照培养箱对盆栽苗进行5个光照强度的处理, 研究其生长发育、叶片解剖结构、叶片及茎色素含量对不同光照强度的响应。结果表明: (1)在试验设置的光照强度范围内, 增强光照强度有利于曼陀罗和紫花曼陀罗的发育及茎、叶生物量的积累; 13 000和18 000 lx两个光照强度下两供试曼陀罗长势最好; 同等光照强度下紫花曼陀罗的株高、基茎粗、叶片数目、茎叶生物量大于曼陀罗, 但差异性不显著。(2)两供试曼陀罗叶片厚度、栅栏组织厚度、海绵组织厚度及气孔密度、气孔指数均随着试验光照强度的增强而增加; 紫花曼陀罗气孔密度及气孔指数明显高于曼陀罗。(3)两供试曼陀罗叶片中叶绿素含量均随试验设置光照强度的增强呈先升后降的趋势; 随试验设置光照强度的增强, 两供试曼陀罗茎中叶绿素a、b及类胡萝卜素含量变化趋势不一致; 茎中花色素苷、类黄酮及总酚含量的变化情况是: 两供试曼陀罗均与光照强度呈正相关, 但紫花曼陀罗比曼陀罗含量高, 这也是紫花曼陀罗花、茎等器官呈紫色的物质基础, 加上气孔密度和气孔指数较大等特性, 使紫花曼陀罗较曼陀罗适应性更强。

Influence of light intensity on growth of Datura stramonium and D.stramonium var.tatual

Aims Our objective was to investigate the influence of light intensity on growth of Datura stramonium and D. stramonium var. tatual.
Methods Plants of D. stramonium var. tatual and D. stramonium were grown under five levels of light intensity in light incubators. We determined plant growth and pigment concentrations in leaves and stems and studied leaf anatomy.
Important findings Both plants grew best under 13 000 and 18 000 lx and had increased leaf and stem biomass with increased light intensity. Under the same light intensity, stem length, basal stem diameter, blade number, bud length, leaf and stem biomass of D. stramonium var. tatual appeared higher than those of D. stramonium, but most differences were statistically insignificant. Leaf, palisade and spongy thickness and stomatal density and index all increased with increasing light intensity. Under the same light intensity, stomatal density and index of D. stramonium var. tatual were significantly higher than those of D. stramonium. For both species, chlorophyll a, b and carotenoid concentrations in leaves showed open downward parabolic trends with increasing light intensity. Chlorophyll a, b and carotenoid concentrations increased with increasing light intensity in stems of D. stramonium var. tatual, but showed open downward parabolic trends in D. stramonium. Concentrations of anthocyanin, flavonoids, and total phenols of the two species increased with increasing light intensity. Stems of D. stramonium var. tatual became purple, presumably due to high levels of anthocyanin, flavonoids and total phenols. Higher levels of anthocyanin, flavonoids and total phenols, together with the higher stomatal density and index, may account for the wider distribution of D. stramonium var. tatual.