Ethanol synthesis, nitrogen, carbohydrates, and growth in tissues from nitrogen fertilized Pseudotsuga menziesii (Mirb.) Franco and Pinus ponderosa Dougl. ex Laws. seedlings |
| |
Authors: | R. G. Kelsey Gladwin Joseph Elizabeth A. Gerson |
| |
Affiliation: | (1) USDA Forest Service, Pacific Northwest Research Station, Corvallis, OR 97331, USA e-mail: kelseyr@fsl.orst.edu Tel.: 541-750-7368; Fax: 541-758-7760, US;(2) Department of Forest Science, Oregon State University, Corvallis, OR 97331, USA, US |
| |
Abstract: | Seedlings of Douglas-fir, Pseudotsuga menziesii (Mirb.) Franco, and ponderosa pine, Pinus ponderosa Dougl. ex Laws., were grown in a controlled environment and fertilized with nutrient solutions containing 150 ppm (+N), or 0 ppm nitrogen (−N). These treatments greatly altered seedling growth, and the concentrations of N and carbohydrates in their tissues. Metabolically active tissues, such as roots, incubated with a limited supply of O2 became hypoxic faster and synthesized more ethanol than less active tissues, such as needles. All tissues that were incubated for 4 h in N2 synthesized ethanol. Needles incubated in N2 and light had much lower quantities of ethanol than needles in N2 and dark, suggesting that O2 from photosynthetsis limited internal anoxia. Most tissues from +N seedlings synthesized greater quantities of ethanol in N2 anoxia than tissues from −N seedlings, probably because they were able to produce more enzymes with a greater availability of N. However, this increase in ethanol synthesis between N treatments was most pronounced in the phloem. Ethanol and soluble sugar concentrations were negatively related in needles and positively related in roots of N+ seedlings, but not −N seedlings. Starch concentrations had no effect on the amount of ethanol produced by any tissue. Regardless of N treatments, all tissues from ponderosa pine produced more N2-induced ethanol than Douglas-fir, in part because its tissues contained different concentrations of soluble sugars and N as a consequence of phenological differences between the species. However, ponderosa pine tissues may also maintain greater quantities of anaerobic enzymes, or their isozymes than Douglas-fir. Received: 22 February 1998 / Accepted 23 June 1998 |
| |
Keywords: | Pseudotsuga menziesii Pinus ponderosa Anoxia Hypoxia Anaerobic respiration |
本文献已被 SpringerLink 等数据库收录! |
|