キク属野生種と栽培ギクの葉身における毛じの密度,長さならびに発達について(育種・遺伝資源)  [in Japanese] Density, Length and Development of Non-glandular Trichome on the Leaves of Wild Chrysanthemums and Chrysanthemum Cultivars(Breeding & Germplasm Resource)  [in Japanese]

キク属野生種10種および栽培ギク20品種において,葉の毛じの密度と長さを観察した.キク属野生種では,葉裏面の毛じ密度に大きな種間差が認められた.また,葉表面より裏面で毛じ密度が高く,毛じの長さは長かった.栽培ギク品種においても同様の傾向がみられたが,野生種より変異の幅は小さかった.ピレオギク系統8913の毛じは他の種よりも長く,形状にも特徴がみられた.ピレオギク系統8913および'苹果香'では,葉表裏面の毛じ密度は0.3本・mm^<-2>以下であった.スプレーギクと毛じ密度が極めて高いイソギクとの種間雑種である'沖の白波'および'キクつくば1号'では,他の品種に比べて葉裏面の毛じ密度が高く,毛じの多少の形質は遺伝することが示唆された.'神馬'の毛じの発達を観察した.葉の発生のごく初期に1個の表皮細胞が,細胞分裂を行いながら外側に向かって伸長し,毛じの発達が始まった.未展開葉の毛じは先端部が紡錘状になり,密生していたが,展開葉では先端部は扁平な楕円形で,密度が疎になることが観察された.

Wild chrysanthemums and chrysanthemum cultivars (Chrysanthemum morifolium Ramat.) form non-glandular trichomes on the leaves. By scanning electron microscope and light microscope, the density and length of non-glandular trichomes on the leaves were measured. Highly significant differences in the density on the abaxial leaf side were found among 10 wild chrysanthemums. More and longer non-glandular trichomes were formed on the abaxial leaf side than the adaxial side. Similar traits were observed among 20 chrysanthemum cultivars but the degree of differences in the variation was minor. C. weyrichii (Maxim.) Miyabe & T. Miyake line 8913 had longer and characteristic non-glandular trichomes compared with other wild chrysanthemums. The densities in C. weyrichii line 8913 and cv. 'Pingguoxiang' were less than 0.3 per mm^2 leaf area. The densities in cv. 'Chrysanthemum Tsukuba No. 1' and cv. 'Oki-no-shiranami' was higher than those other chrysanthemum cultivars. They are interspecific hybridizations between C. morifolium and C. pacificum that was extremely hairy. The density of non-glandular trichome may be inherited. Non-glandular trichomes were initiated by the enlargement of single epidermal cells followed by anticlinal devision on leaf primordia in cv. 'Jimba'. The head of non-glandular trichome was spindle-shaped on developing leaves but became a flat ellipse on expanded leaves. The density decreased as the leaf expanded.