NITROGEN-SOURCE EFFECTS ON AL-TOXICITY IN NONMYCORRHIZAL AND MYCORRHIZAL PITCH PINE (PINUS-RIGIDA) SEEDLINGS .1. GROWTH AND NUTRITION

被引:32
作者
CUMMING, JR
WEINSTEIN, LH
机构
[1] CORNELL UNIV,DEPT NAT RESOURCES,ITHACA,NY 14853
[2] CORNELL UNIV,BOYCE THOMPSON INST PLANT RES,ITHACA,NY 14853
来源
CANADIAN JOURNAL OF BOTANY-REVUE CANADIENNE DE BOTANIQUE | 1990年 / 68卷 / 12期
关键词
PINUS-RIGIDA; ECTOMYCORRHIZAL; ALUMINUM TOXICITY; NITROGEN SOURCE;
D O I
10.1139/b90-334
中图分类号
Q94 [植物学];
学科分类号
071001 ;
摘要
Previous studies indicated that the association of Pisolithus tinctorius with pitch pine (Pinus rigida) seedling roots prevented Al toxicity from developing when seedlings were exposed to 200-mu-M Al in sand culture. The ectomycorrhizal fungus reduced seedling Al uptake and maintained P nutrition when seedlings were cultured on one-quarter strength Johnson's solution containing 3.5 and 0.5 mM NO3- and NH4+, respectively. To broaden the scope of these findings, nonmycorrhizal and mycorrhizal seedlings were grown on one-quarter strength Johnson's solution modified to contain NO3-, NH4NO3, or NH4+. Seedlings were exposed to 0 or 200-mu-M Al for 6 weeks. Reductions in seedling height growth rate and final shoot weight in response to Al occurred in nonmycorrhizal seedlings grown with NO3-. Root weights were consistently reduced by Al under all N-source combinations. Increasing proportions of NO3- in the nutrient solution increased cation accumulation in roots and shoots and depressed tissue anion concentrations. The coprecipitation of Al and P(i) i roots of Al-treated seedlings further limited P availability in this treatment. Mycorrhizal infection maintained growth and foliar P levels under Al exposure, suggesting that Al-induced P limitation was a critical factor in nonmycorrhizal seedlings grown on primarily NO3- -based nutrient solutions.
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页码:2644 / 2652
页数:9
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