A Distribution and Ultrastructure of Laticifers in the Phylloclade of iEuphorbia caducifolia/iHaines, a Potential Hydrocarbon Yielding CAM Plant

摘要

The present study describes the anatomy, distribution, morphology and ultrastructure of laticifer system in the phylloclades of Euphorbia caducifolia Haines (Family Euphorbiaceae), a potential biofuel yielding, Crassulacean Acid Metabolism (CAM) plant for the first time using light and transmission electron microscopy (TEM). Histochemical tests were performed to identify the principal components of latex using a variety of stains. In cross section, the phylloclade is composed of four distinct regions: the epidermis, cortex, vascular cylinder and pith. The phylloclade anatomy indicated xeromorphic characters and provided an insight about its capacity to grow with very little rainfall and/or inputs on dry or marginal lands. Non-articulated laticifers are present in the cortex, vascular cylinder and pith, but their frequency varies with the tissue type. Highest laticifer frequency was observed in vascular cylinder (9.6%) followed by cortex (3.9%) and pith regions (1.9%). In contrast, laticifer index was found to be higher in the pith (12.7%) followed by cortex (3.8%) and vascular cylinder (2.3%). The discovery of a system of laticifers in E. caducifolia not described earlier could also be of taxonomic value. The histo-chemical tests revealed the presence of lipids, phenols, flavonoids, protein and starch in laticifer. As described by TEM observations laticifers contained distinct cell wall, nucleus and cytoplasm with ribosomes, small and big vacuoles, mitochondria, endoplasmic reticulum, plastids and osmophilic bodies. The lipophilic compounds present in the latex of this species could be used as chemical feedstock for the production of biofuels.