بررسي اثر متقابل فسفر و پتاسيم بر روي تغيير پروتيين هاي گلايسينين و -B كونگلايسينين سويا در برگ وكالوس

Growth and development of three annual medicago species under different air and root zone temperatures

Growth and development of three annual Medicago species under different air and root zone temperatures annual medics are the most commonly grown forage legume in ley-farming systems. However, its lack of persistence under sever winter and early spring conditions reduced its utilization in cold zones of the world. Cold tolerance (between 0-5??C) has been shown to be the most important factor in Winter and early Spring survival. Selection for cold tolerance is difficult due to the complexity of field evaluation. A method of selection performed under environmentally-controlled conditions has been used for the identification of genotypes having superior cold tolerance. Three annual medic species (Medicago polymorpha cv. Santiago, Medicago radiata cv. Radiata, and species Medicago rigidula cv. Rigidula), were evaluated for traits under three levels of day/night air temperatures (DNAT, 15/10, 20/15, and 25/20 ?¾0.2¢?C) and four root-zone temperatures (RZT, 5, 10, 15, and 20?¾0.2¢?C). The experimental design was a split split-plot with treatments organized following a randomized complete block design with three replications. The result showed that M. rigidula and M. polymorpha were the best cultivars for leaf, stem and root dry matter, plant height, leaf and stem to root ratio, leaf to stem ratio, leaf number and leaf area at low and moderate RZT respectively. At low RZTs (5 and 10¢?C) and high DNAT (25¢?C) M. rigidula produced the most stem node number, leaf number, leaf area, leaf dry matter, stem dry matter and leaf to stem ratio. Thus M. rigidula performed well at low RZT and high DNAT and probably the most promising for the production of herbage at low temperature.