Transpiracion, resistencia estomatica y potenciales hidricos en manzano 'Golden Delicious' injertado sobre portainjertos clonales | Transpiration, stomatal resistance and water potential in 'Golden Delicious' apple grafted onto clonal rootstocks
2002
Quezada, R.A.P. | Roman, A.E.B. | Castaneda, C.L.
In 1997, the performance of MM.111, MM.106, M.7, and M26 apple rootstocks grafted with two-year-old Golden Delicious apple was studied in the field. Treatments were 1) Fertigation (FR) with 100, 70, and 150 mg L(-1) of N, P, and K every time watering was necessary, 2) 28, 18, and 42 g of N, P, and K per tree per year at the end of the season, 3) mulching with black plastic (AC) plus 400 mm of rain simulating rainfed conditions of the apple-growing regions of the country, and 4) rainfed conditions on bare soil (TM). The first three treatments were applied in the large plot. In the medium plot, two treatments were applied: with and without organic fertilization to the soil before plantation. In the small plot, the rootstocks were tested. These factors and values resulted in a design of subdivided plots with two repetitions and one tree as the experimental unit. Every two months, mature leaves from the terminal end of the shoot were sampled to determine proline content. Transpiration, stomatal resistance, and water potential and its components were also measured, and water use efficiency was estimated. The results were inconsistent and showed low proline concentrations in the leaves (0.23 mg g(-1)). Transpiration was up to two times higher in FR and AC than in TM. The highest WUE was in AC followed by FR, tending to increase, while TM decreased through the season. The rootstock MM.111 had the highest WUE. Leaf turgor was maintained (0.3 MPa) in TM, while in FR and AC it was up to twice as high.
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