Abstract:

The anatomical structure and stomatal characteristics on the leaf of Ginkgo biloba var. epiphylla found firstly in China from Yiyuan county of Shandong Province were studied in this paper. The results of analyses showed that the mesophyll of normal leaf blades had the differentiation of palisade tissue and spongy tissue,but the mesophyll of leaf blades with ovule-like organ was composed of the homeotypic parenchyma cells. There were ridges on the sites with ovule-like organ,and the mesophyll cells in ridges were composed of large parenchyma cells. The location of their veins was divided into two types,I.e. distributing at the both sides of the ridge and distributing just above the ridge. Moreover,the veins in ridges were denser than those of normal sites. Three to four layers lignified cells located at the lateral border of phloem,in the ground tissue of the petiole of the leaf with ovule-like organ,which was reported for the first time. The stomata of G. biloba var. epiphylla were amphistomatic,the stomatal apparatus was monocytic; and stomata in the lower epidermis of some leaf blades with ovule-like organ arranged irregularly in rows along the veins. The genetic relationships among G. biloba var. epiphylla,fern,and other gymnosperms were discussed.

Key words: Ginkgo biloba var. epiphylla, the leaf with ovule-like organ, anatomical structure, stomatal characteristics