ISSN:
1432-0789
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Geosciences
,
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Notes:
Abstract We measured the growth, nutrition, and N assimilation of arbuscular-mycorrhizal and non-mycorrhizal lettuce (Lactuca sativa L.) as affected by forms of N and drought. Moisture was maintained at 80% water-holding capacity, and N was applied as NO3 –, NH4 +, or NO3 –/NH4 + (3:1, 1:1, or 1:3). The growth of Glomus fasciculatum-colonized plants was comparable to that of uncolonized P-supplemented plants when N was provided as NH4 + or combined NO3 –/NH4 +. When N was supplied solely as NO3 –, G. fasciculatum-colonized plants produced a higher yield than P-fertilized plants, suggesting that the uptake and/or assimilation of NO3 – was particularly affected by mycorrhizal status in this water-limited situation. Nutrient availability, except Ca, was less limited for mycorrhizal plants than for P-fertilized plants. P fertilization increased the growth, glutamine synthetase activity, and protein content of lettuce to the same extent that G. fasciculatum colonization did when N was applied as NH4 +. With NO3 –-fertilization, G. fasciculatum-colonized plants showed increased growth, nitrate reductase activity, and protein content compared to P-fertilizer treatment. Plants colonized by G. mosseae showed increased photosynthetic activity and proline acumulation, and these mechanisms may be important in adaptation by the plant to drought conditions. The present results confirmed that under drought conditions, the uptake or metabolism of N forms is particularly affected in mycorrhizal fungi-colonized plants, depending on the mycorrhizal endophyte and the N source added. Thus the significance of arbuscular-mycorrhizal fungus selection for plant growth in drought conditions is a consideration for management strategy.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00384448
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