Water transfer in a papaya-corn culture system
2014
Marler, T.E.
‘Tainung 2’ and ‘Sunrise’ papaya seedlings were grown in split-root containers. ‘Honey Jean 3’ sweet corn seeds were planted in one of the two containers that comprised each split-root papaya system. Following establishment of the corn seedlings, the papaya-corn systems were subjected to one of three treatments: 1) both halves of the papaya roots were well-watered (control); 2) both halves of the papaya roots received no water; (3) the papaya root half without the corn seedling was watered but the half with the corn seedling received no water. Pre-dawn leaf relative water content (RWC) and mid-morning stomatal conductance of corn leaves were the response variables used to quantify drought stress. Stomatal conductance reached zero by day 10, when RWC of treatment 2 plants was less than 50% and that of treatment 3 plants was 80%. At this stage, half of the remaining replications in treatment 3 were treated by cutting the connection between the roots in the dry compartment and the base of the papaya stem. This procedure relieved competition between the two species, but also eliminated the watered half of the papaya roots as a possible source of water for the corn plants. Leaf RWC of the corn plants relieved of papaya root competition declined to below that of corn plants within intact treatment 3 papaya split root systems. These results indicate hydraulic redistribution occurred from papaya roots in the watered pots to the corn plants. Water redistribution within papaya plants may have impacts on hydrologic processes, and should be considered when scaling fluxes to the orchard level.
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