ISSN:
1573-5036
Keywords:
Carbohydrate
;
Disease
;
resistance
;
Hormones
;
Micronutrients
;
Phosphate
;
Physiology
;
VA mycorrhizae
;
Water uptake
Source:
Springer Online Journal Archives 1860-2000
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Notes:
Summary The fungi of vesicular-arbuscular mycorrhizae colonize considerable portions of the root system and in spite of the carbon drain they impose on the host plant, their presence within the root tissues can positively influence several aspects of the host plant's physiology. In the majority of cases, improved phosphate uptake is the primary cause of growth and yield enhancements in the mycorrhizal plants. Mycorrhizal roots have different phosphate absorption kinetics and lower threshold values than nonmycorrhizal roots. The external hyphae developing around mycorrhizae explore a large volume of soil and absorb available phosphate beyond the depletion zone at the root surface. Phosphate accumulating in the external fungal hyphae is translocated to the internal mycelium by a well-developed transport system and transferred to the host tissues mainly across the intracellular arbuscules. Certain specialized enzyme activities are specifically associated with this alternative pathway of phosphate nutrition in mycorrhizal plants. Improved phosphate nutrition is not always sufficient to explain the observed effects of vesicular-arbuscular mycorrhizae on the host plant's physiology.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02182655
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