UV–B辐射对神农香菊叶片表皮毛及其分泌物的影响

Effects of UV–B radiation on the trichomes and secretions of leaves of Dendranthema indicum var. aromaticum

以神农香菊(Dendranthema indicum var.aromaticum)为材料,用紫外光UV–B对其进行辐射处理,处理时间分别为0(CK)、1、3、5、7 d,研究其对叶片表皮毛形态、密度和叶片表面分泌物的影响。结果表明:UV–B处理后的头状腺毛中部出现不规则凹陷,甚至扭曲;"T"形非腺毛出现顶细胞破裂、脱落现象;头状腺毛和"T"形非腺毛的密度均随处理天数的增加,呈先增加后减少的趋势,两者均在处理1 d时达最大,此时叶尖、叶中、叶基的头状腺毛密度每视野分别为16.00、13.67、18.67根,叶片下表皮的"T"形非腺毛密度每视野达43.84根;叶片表面分泌物中α–蒎烯、α–荜澄茄油烯的相对含量变化不明显,而杜松萜烯、1–石竹烯的相对含量变化较大,均在处理3 d时相对含量达到最高,分别为19.45%和14.71%;樟脑类物质和醇酮类物质的相对含量呈现先升高后降低的变化趋势,在第1天或第3天达到最大值,第7天降到最低。

In this experiment,Dendranthema indicum var.aromaticum was used as material and five treatments of0(CK),1,3,5and7d radiation with UV–B were designed to study the effect of ultraviolet radiation on the morphology,densityof the trichomes and the surface secretion of leaves.The results showed that glandular trichomes of UV–B treatmentappeared irregular depressions in the middle,or even distortions.The apical cells of“T”shape hairs with non–glandularruptured or even fallen off.As the radiation days increased,the densities of glandular trichomes and“T”shape hairs withnon–glandular showed a trend of first increased then decreased.Their densities were the highest on the lower epidermisof leaves in the treatment of1d,which the glandular trichomes numbers on the tip,middle and base of leaf were16.00,13.67and18.67respectively in each vision field and“T”shape hairs with non–glandular numbers were43.84in eachvision field.The relative content of leaf surface secretion of alpha pinene and alpha cubebene did not change significantly,while cadinene and1–caryophyllene were higher volatility and reached the highest level of19.45%and14.71%with3dradiation.Relative percentage content of camphor,alcohols and ketones presented a trend of first increased thendecreased with the increase of radiation days.Their content reached largest in1d or3d and dropped to the lowest in7d.