Influence of controlled water supply on shoot and root development of young peach trees.
1995
Hipps N.A. | Pages L. | Huguet J.G. | Serra V.
Three controlled water supply treatments were applied to l-year-old peach trees grown in root observation boxes. The treatments were: I0, growth medium maintained at 50% field capacity; I1, water supplied when daily net tree stem diameter change was negative or zero for l day; I3 as for I0 except that water was applied after net daily stem diameter change was negative or zero for 3 consecutive days. Trees in treatment I0 had the greatest mean daily first-order shoot growth rates, and trees in treatment I3 had the lowest shoot growth rates. Because leaf production rate (apparent plastochron) of first-order shoots was unaffected by treatment, differences in shoot length were due to differences in internode extension and not to the number of internodes. Trees in treatment I0 had a greater number of second-order shoot axes than trees in treatment I1 or I3. Furthermore, an increase in the rate of growth of the first-order shoot axis was associated with an increased tendency for branching (i.e., the development of sylleptic second-order shoots). Increased leaf length was also associated with more frequent watering. Trees in treatment I0 had the greatest root lengths and dry weights, and this was attributed to a greater number of first- and second-order (lateral) root axes compared with trees in the I1 and I3 treatments. The extension rate and apical diameter of first-order roots were reduced by the I3 treatment. The density of second-order roots along primary root axes was not affected by any of the treatments.
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