The increasing need for herbal medicines requires the study of not only biological resources of medical plants, but also methods for their reproduction. Of special value are the medicinal plants that have a long history of success in traditional medicine. One of such plants is Eucommia ulmoides Oliv., which belongs to a rare relict species growing in natural conditions, for the most part, in the undergrowth of humid subtropical forests in China, mainly in the middle course of the Yangtze river. E. ulmoides compares favorably with most subtropical plants owing to its significant frost resistance, which makes it possible to cultivate it outside the humid subtropics. It has been widely introduced in Krasnodar Krai and in the Republic of Adygea (Russia) since the mid-20th century and successfully adapted to various environmental conditions in the Northwest Caucasus. The increasing demand for E. ulmoides bark can only be satisfied by laying out industrial plantations. However, the difficulties encountered in the traditional seed reproduction of E. ulmoides (dioecious species, pollen low quality, parthenocarpy, prolonged seed dormancy, irregular fruiting, long juvenile period, etc.) make scientists turn to modern biotechnological methods of plant propagation. While considering cultivation of planting material, we should focus on highly efficient methods that ensure stable and mass reproduction of the plants under study. An important role is played here by in vitro plant regeneration. The effectiveness of biotechnology methods is due to a reduction in timing of obtaining a large number of vegetative progeny of plants difficult for propagation, as well saving of the area required for their cultivation. The conditions for producing an aseptic culture of E. ulmoides were chosen based on the results of the studies. The highest degree of sterilization of E. ulmoides shoot segments was achieved when the explants were sequentially immersed first in 70 % ethanol (30 s) and then in 0.1 % mercuric chloride solution (5 min). With such a sterilization procedure, 63.3 % of the studied cuttings were made sterile, and 56.7 % of them proved to be viable. The optimal composition of the nutrient medium for regeneration of E. ulmoides microshoots has been determined: MS medium complemented with 1 mg/L 6-Benzylaminopurine (BAP) + 0.2 mg/L 1-Naphthaleneacetic acid (NAA). The best media for explant rooting are the following: 2/3 MS + 1.5 mg/L NAA + 30 g sucrose + 7 g agar; 2/3 MS + 1 mg/L NAA + 0.4 mg/L IBA + 30 g sucrose + 7 g agar.
The Relationship Between Leaf Area and Light Interception by Spur and Extension Shoot Leaves and Apple Orchard Productivity
