Physiological and anatomical responses of cowpea (vigna unguiculata (L.) walp) to short durations of waterlogging
1997
Abuhay Takele (IAR, Addis Abeba (Ethiopia)) | McDavid, C.R.
The effects of short durations of waterlogging on greenhouse grown plants of three cultivars of cowpea with differing levels of tolerance to waterlogging were investigated. The cultivars included were A-1809 (tolerant), IT-83S-898 (intermediate) and UCR-A-31 (susceptible). Leaf relative water content (LRWc) was reduced in the susceptible cultivars, and this was associated with a greater reduction in stomatal resistance (rs) and a greater reduction in dry matter production in the former. Leaf water potential, leaf area (LA) per plant, transpiration rate and net photosynthesis (Pa) were all reduced by waterlogging but there was no difference in cultivar response for these parameter. After the first cycle of waterlogging there was little change in leaf water potential, leaf area or dry weight of waterlogged plants except for a small but significant increase in leaf area during the third cycle in the severe waterlogging (SWL) treatment. Waterlogging greatly stimulated the development of aerenchyma (air spaces) within the basis of the stem and main root. The magnitude and distribution of the caltivars varied between cultivars. It is suggested that the differences between cowpea cultivars A-1809, IT-83S-898 AND UCR-a-31 with respect to water relations, leaf area development, dry matter accumulations in response to short durations of waterlogging were related to the greater degree of root damage in the susceptible cultivars and to the greater development of lysigenous cavities in the stem base and primary roots of the tolerant cultivars.
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