Author
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Sinclair, Thomas |
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Submitted to: Field Crops Research
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 8/26/2000 Publication Date: N/A Citation: N/A Interpretive Summary: Problem: While drought survival of row crops in industrialized agriculture is not an important issue, survival of severe water deficits by perennial crops and subsistence row crops can be essential to the sustainability of these systems. This analysis was undertaken to identify those plant traits that are especially beneficial in allowing prolonged survival of crops under severe drought conditions. Accomplishments: This analysis undertaken by an ARS-USDA scientist at Gainesville, FL, demonstrated that it is especially important to have leaves on the plant that seal themselves very well against water loss under drought conditions. Once this trait has been achieved, it is beneficial to have leaves that can dehydrate to a substantial extent before reaching a lethal water content. Usefulness: This research can be used to target plant breeding programs to improve perennial crops, such as grasses and legumes used as pasture and rangeland forages. Improved plant traits for drought survival will increase the persistence of improved pastures and result in increased profits for growers. Technical Abstract: Plant survival of severe drought may be especially important in perennial crop species such as forages, which might be subjected to prolonged water deficit at some time during their life cycles. While a number of plant traits have been discussed as being beneficial in increasing drought survival, there is virtually no quantitative evidence concerning the relative merits of these traits. This analysis was undertaken with a relatively simple model of plant water balance to calculate the duration of crop survival during exposure to severe water deficits. This analysis clearly indicated that a low leaf epidermal conductance was an essential factor in prolonging plant survival under drought. The benefit of low epidermal conductance was greatest at a low value (0.10 mm s 1), which is less than has been reported for annual row-crop species. Investigation of the variability and inheritance of epidermal conductance in perennial crops, which may be subjected to survival-threatening drought, were identified as prime topics for future research. Once a low epidermal conductance has been achieved, additional increases in prolonging plant survival of severe drought were obtained as a result of leaf shedding and a low lethal relative water content for leaves. |
