EFFECT OF ANIMAL HORMONES ON THE MORPHOLOGICAL, CHEMICAL AND ANATOMINCAL STRUCTURE OF POTHOS (Scindapsus aureus) PLANT

Abstract

Striking similarities actually exist between plant and animal tissues, as far as consideration concerns cell structure and biological processes. Through this concept, two animal hormones were added at different concentrations to the drenching solution of pothos (Scindapsus aureus) plants, in a trial to examine their possible effects on growth and development of a representative member of the plant kingdom. This study was conducted in the Faculty of Agriculture, Cairo University, during the two successive seasons of 2003/2004 and 2004/2005. Three concentrations were used for an estrogenic hormone (ethinyl estradiol at 0.1, 0.15 and 0.2 ppm), two concentrations for a progestational hormone (lynestrenol at 1 and 1.5 ppm) and a combination of the two zoochemical agents (ethinyl estradiol at 0.1 + lynestrenol at 1 ppm). The plants were studied morphologically, chemically and anatomically. The morphology, included plant height, number of leaves per plant, leaf area, fresh and dry weights of leaves, main stem diameter, and its fresh and dry weights, root length, and its fresh and dry weights. Calculations were made for the stem cross-sectional area, and also for the percentage increase of the above mentioned parameters for the above-ground plant parts, in association with the most effective treatment in the study (ethinyl estradiol at 0.1 ppm) in comparison to control morphological values. The chemical analysis included the pigment content in fresh leaves, as well as the nitrogen, phosphorus, and potassium percentages in dry leaves. The anatomical description included the laminar thickness, midrib thickness, number of vascular bundles per midrib, thickness of petiole, and the number of vascular bundles per petiole. Calculations were made for the midrib and petiole cross-sectional areas, and their vascular densities, in addition to the percentage increase of the above mentioned anatomical parameters, in association with the most effective treatment in the study (ethinyl estradiol at 0.1 ppm) in comparison to control anatomical values. Statistical analysis of the results revealed a clear response to hormones in the form of considerable enhancement of plant height, as well as leaf and stem parameters. Limited increments were recorded for root parameters. Increased nitrogen and phosphorus percentages in dry leaves were also recorded. The best enhancing effects were generally recorded with ethinyl estradiol at 0.1 ppm.. It can be concluded that estrogen, may represent a form of exogenous biological growth regulator in the field of plant promotion. These enhancing effects might be explained by the presence of estrogen receptors (already confirmed in literature) and /or progesterone receptors in plant tissue. Alternatively, animal hormones may be inducing plant cytokinins, or else performing cytokinin-like action (morphogenesis). Further experimental studies, may be recommended, such as using lower concentrations of these hormones, and comparing drenching to spraying, in addition to manipulating the plants differently as regards fertilization, and comparison of animal hormones with other known growth regulators. These zoochemical agents may prove to be beneficial in induction of plant tissue culture. However, the life time duration of treated plants should be studied in the presence of such hormones. The plant tissue content of these hormones and their degradation products, should also be estimated, as they may, later on, be used for increasing the production of edible, medicinal, or aromatic plants, with subsequent possible effects on human health.