Effect of rootstock on growth and water use efficiency of Hevea during water stress
1999
Bastiah Ahmad
The effects of three monoclonal Hevea rootstocks on growth, water relations parameters, proline content in leaf and water use efficiency of RRIM 901 scion clone during prolonged cycles of water stress were studied. The plants, + raised in plastic containers in the glass house, were subjected to cycles of water stress for over a year by irrigating either every alternate day (moderate stress) or once in four days (severe stress). The three rootstocks imparted different stomatal + responses to the scion. RRIM 623 rootstock had drought avoidance characteristics as the plants minimised water loss during severe water stress through effective stomatal control in the scion shoot and by having deep rooting characteristics. In contrast, + GT 1 rootstock responded to drought by keeping stomata partially opened as soil dehydration intensified allowing leaf photosynthesis to continue. In common with RRIM 623 rootstock, plants on GT 1 rootstock had low pre-dawn leaf water potential and high + root: shoot ratio reflecting their deep rooting characteristics. Plants on RRIM 600 rootstock was also very sensitive to water stress but they seem to lack deep rooting characteristics. Plants on GT 1 and RRIM 600 rootstocks tend to accumulate proline in+ leaves indicating their ability for osmoregulation. Data obtained in this study indicated that plants on GT 1 and RRIM 623 rootstocks are better adapted to prolonged drought than those on RRIM 600 rootstock by virtue of their deep rooting + characteristics.
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