Morphological characteristics of leaf epidermis and size variation of leaf,flower and fruit in different ploidy levels in Buddleja macrostachya (Buddlejaceae)

Buddleja macrostachya （Buddlejaceae） is a widespread shrub native to the Sino-Himalayan mountains and beyond. It has been found to occur at two ploidy levels, hexaploid, 2n=6x=114 and dodecaploid, 2n= 12x=228. To determine if morphological characters might be used as indicators of ploidy levels, we measured floral and fruit length, relative and absolute leaf size, trichome density on both leaf surfaces, and stomatal density and length in different populations orB. macrostachya. In general, flower and fruit length, absolute leaf size, and stomatal length in,eased with an increase at ploidy level （P〈0.01）, whereas adaxial cell and stomatal density decreased with an increase at ploidy level （P〈0.01）. We found no conspicuous differences in relative leaf size （P〉0.05） in different populations. Other characters studied such as trichome type, cuticular membrane and ornamentation of stomata, cell and stomatal shape, and anticlinal wall pattern were quite constant in this species. Thus it appears that flower and fruit length, absolute leaf size, and stomatal frequency and length can be used to distinguish hexaptoid from dodecaploid cytotypes either in the field or in herbarium specimens.

光温对3种醉鱼草属植物种子萌发的影响

密蒙花、七里香和大序醉鱼草3种醉鱼草的种子细小,千粒重仅12￣58mg,但形态有差异,可以进行种类区分。种子充分吸水后,在20￣25℃条件下于5￣10d内就能迅速萌发,15d时发芽率达到75%以上。光照强度21.6￣32.4μmol·m-2·s-1和光照时间12￣16h·d-1均可显著提高七里香种子的发芽率,但光照抑制密蒙花种子萌发,而对大序醉鱼草种子萌发没有明显影响。种子苗移栽后3￣5d,真叶转绿,90%的幼苗可形成健壮植株。