Leaf anatomical structure of six Aquilaria species
Agarwood is a resin wood, which formed in the stem of Aquilaria and may represent the most prized non-timber forest product, which can be used in fragrances, incense, medicines, aromatherapy, and religious ceremonies.Aquilaria is an endangered genus due to the excessive exploitation of its precious agarwood, while not all Aquilaria species can produce agarwood effectively or different Aquilaria species produce agarwood with distinctive fragrances and price.Therefore, it is an important task to improve the identification methods of Aquilaria species.In order to identify the Aquilaria species, the leaf anatomical structures of selected Aquilaria species were compared in this study.The mature leaves of the six Aquilaria species (Thymelaeaceae) were studied with light microscopy and paraffin sectioning, and twelve quantitative traits of the leaves were measured and analyzed.The result showed that the leaf structures of six Aquilaria species were similar.All leaves showed the xerophytic feature.All leaves were typical bifacial type and were composed of epidermis, mesophyll and vein.The epidermis consisted of single layer epidermal cells.The upper epidermis were much thicker than the lower epidermis.The sunken stomata existed only in lower epidermis which was sporadically covered by hairs.The stomata were of anomocytic type.The mesophyll was well developed which were composed of palisade parenchyma, spongy parenchyma and lithocyst.The palisade parenchyma was composed of 1-2 layers of cylindrical cells, in which many rectangular lithocyst arranged perpendicularly to the epidermis.The hypodermis was located in spongy parenchyma, which was composed of idioblasts.The micrib belonging to bicollateral bundle was well developed.The bundle sheath and pith both contain a number of idioblasts.ANOVA analysis showed that the eleven quantitative traits were significantly different among six species, except for ratio of palisade to spongy tissue.Clustering analysis showed that six species were clustered into three main groups.Group 1 consisted of A.sinensis, A.crassna and A.banaensis;Group 2 consisted of A.baillonii and A.malaccensis;Group 3 only consisted of A.yunnanensis.The results provides some new information for the species identification, but also is of great significance for the conservation and utilization of Aquilaria spp.
国家科技期刊平台
NSTL
万方数据
维普
