|Abstract or Summary
- The effects of N and Zn treatments on growth and nutrient composition
of sweet cherry trees were investigated in greenhouse and
outdoor sand culture experiments. In these studies, one-year old
clonal F12-1 sweet cherry trees were grown in dithizone purified
nutrient solution consisting of three levels of N (3O, 80, and 224 ppm
N) in factorial combination with four levels of Zn (0, .025, 1.25, and
5 ppm Zn). Dry weights and the concentrations of the major and
minor elements were measured for the roots, trunks, and leaves
for each tree.
The results show that the N levels significantly increased the
dry weights of all plant parts under the two study conditions. Increasing the Zn level from 0 to 1.25 ppm significantly increased the dry
weights of the various parts of trees from the two locations. Application
of 5 ppm Zn produced significantly less increases in dry weights
of the various parts of the outdoor trees, but slightly decreased the
dry weights of all plant parts in the greenhouse.
The N levels significantly increased both the concentration and
uptake of N by the leaves and various parts of trees from the two locations.
The Zn treatments decreased the concentration of N in leaves
of the greenhouse trees at the N₁ level but increased it outdoors.
Both the N and Zn levels had variable effects on the concentrations
of P, K, Ca, Mg, Mn, Fe, Cu, and B in the various parts of trees
from the two locations, but generally increased their uptake by these
plant parts. The N and Zn treatments consistently increased both the
concentration and uptake of Zn by leaves and various parts of the
greenhouse and outdoor trees. The hypothesis was proposed that N
is antagonistic to Zn uptake by leaves of plants. The results of this
investigation gave no evidence in support of this hypothesis. Instead,
the data show some evidence that N is synergistic to Zn in that an
increase in N uptake by the leaves resulted in a corresponding increase
in Zn uptake. This phenomenon was also evidenced in the various
sections of the trees analyzed. The conclusion reached was
that N is synergistically related to Zn in plant and that this
relationship can be effectively utilized to control Zn deficiency in the
field, of practical significance in commercial fruit production.