Đang chuẩn bị nút TẢI XUỐNG, xin hãy chờ
Tải xuống
Tuyển tập các báo cáo nghiên cứu về sinh học được đăng trên tạp chí lâm nghiệp đề tài: Arginine and the shade tolerance of white spruce saplings entering winter dormancy. | JOURNAL OF FOREST SCIENCE 56 2010 2 77-83 Arginine and the shade tolerance of white spruce saplings entering winter dormancy D. J. Durzan Department of Plant Sciences University of California Davis USA ABSTRACT Shade-tolerant white spruce saplings grown at 100 45 25 and 13 natural light for four years and entering winter dormancy modified their growth habit and redistributed the total soluble N among needles roots and stems with buds mainly to arginine N. Most free amino acid N was found in roots in saplings at full light and the least at 13 light. Glutamate glutamine and aspartate N contributed to the accumulation of soluble arginine N. Arginine-derived y-guanidinobutyric acid agmatine and an unidentified guanidino compound accumulated mainly in stems with buds at 25 and 13 light. The profiling N metabolism and arginine-derived guanidino compounds extend models for shade tolerance based mainly on photosynthesis respiration and carbon gain. Keywords amino acids arginine guanidino compounds nitrogen Piceaglauca shade tolerance winter dormancy White spruce Picea glauca Moench. Voss. is a shade-tolerant conifer in forest understories. Prior studies focused on the shade-induced changes in leaf morphology and physiology photosynthesis respiration and dry matter Kramer Kozlowski 1979 Mitamura et al. 2008 . Although arginine 2-amino-5-guanidinovaleric acid was first isolated from the soluble nitrogen N and proteins of Picea Pinus and Abies seedlings Schulze 1896 very little is known about how arginine metabolism relates to shade tolerance and to the survival of saplings under field conditions and in N-poor forest soils. Isotopic studies with conifers demonstrated that arginine was synthesized de novo via the urea or ornithine cycle and enriched the soluble N pool by protein turnover Durzan 1968 1969 . The fate of the carbon of arginine in white spruce trees entering winter dormancy was traced to several guanidino compounds Durzan 1968 1969 . The transfer of the amidino .
