Change in B content of olive (Olea europaea L.) leaves during anthesis reveals the appearance of a potent B sink. This phenomenon was more marked in young leaves of bearing trees with a high degree of flowering than in nonbearing trees with a low degree of flowering. Applying B to the leaves at the time of anthesis increased the B concentrations in leaf blades, petioles, bark of the bearing shoot, and flowers and fruit 3 days after treatment. The results suggest that B is mobilized from young leaves during anthesis to supply the requirements of flowers and young fruit.
A. Delgado, M. Benlloch and R. Fernández-Escobar
C. Navarro, R. Fernández-Escobar and M. Benlloch
A low-pressure injection method for introducing chemical formulations into trees is presented. The apparatus consists of a plastic injector and a tube providing a pressure of 60 to 80 kPa, which is below the injurious level for the xylem. The efficiency of the method was determined by injecting PTS, a marker of apoplastic flux dye solutions, and rubidium chloride into young trees, main scaffolds, or tree trunks. The depth of the hole drilled) and the number of injections necessary to distribute the solutions was also determined. The injected solutions moved mainly upward through the older rings of the xylem, suggesting that uptake is directly controlled by the transpiration rate. A single injection was enough to distribute solutions in scaffolds with a diameter of 8 cm, but two injections were necessary for 17-cm-diameter trunks. According to the results, the injection method was effective in introducing chemicals into olive (Olea europaea L.) trees. The method is easy to use, safe and economical and does not involve special equipment. Chemical name used: trisodium, 3-hydroxi-5,8,10-pyrenetrisulfonate (PTS).
R. Fernández-Escobar, D. Barranco and M. Benlloch
Chlorotic `Manzanillo' olive (Olea europaea L.) trees and `Maycrest' peach [Prunus persica (L.) Batsch] trees were injected with Fe solutions using an apparatus that consisted of a plastic injector and a pressurized latex tube containing the solution to be injected. Injections were made on various dates from Sept. 1987 to July 1988. All treatments increased chlorophyll content compared to that of the control. Ferrous sulfate was the most effective Fe compound in alleviating chlorosis; its effect lasted for two seasons in peach and for at least three seasons in olive. Also, ferrous sulfate increased vegetative growth and affected cropping the year following injections. Ferrous sulfate at 0.5% to 1% is recommended to reduce the risk of foliar burning. The injection method effectively introduced Fe compounds into olive and peach trees.
R. Fernandez-Escobar, M. Benlloch, C. Navarro and G.C. Martin
GA3 scaffold injections applied between May and November to nonbearing olive (Olea europea L.) trees inhibited flowering the following year, increased shoot width when applied in May, June, and July, and increased inflorescence length when applied in November and February. Fruit removal and seed destruction were effective in improving the return bloom in `Manzanillo' olives when done before endocarp sclerification. Depending on-the year, endocarp sclerification takes place 7 to 8 weeks after full bloom (AFB), usually about 1 July. Fruit removal had no effect on flowering when done after this time. Scaffold injection of paclobutrazol applied to bearing trees between May and September did not affect flowering the following year. The results of our research supports the hypothesis that olive flower induction occurs around the time of endocarp sclerification. Chemical names used: gibberellic acid (GA3), (2RS,3RS)-1-(4-chlorophenyl)-4-dimethyl-2-1,2-4-triazol-1-yl) pentan-3-ol(paclobutrazol).
M. Benlloch, F. Arboleda, D. Barranco and R. Fernández-Escobar
The influence of sodium and boron excess in the irrigation water on shoot growth and on the distribution of these elements within various leaf types was studied on rooted olive cuttings (Olea europaea L.). `Lechín de Granada' was more tolerant than `Manzanillo' to sodium excess, as indicated by greater shoot growth and lower accumulation of sodium, especially in the young leaves. `Picual' was more tolerant to boron than `Manzanillo', with less accumulation in adult leaves. The results suggest the avoidance of toxicity by an ionic exclusion mechanism that is more effective in some cultivars than others. Also, the results reveal cultivar differences in the tolerance of olive to sodium and boron excess in the culture medium.