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Catalase activity in grapevine (Vitis vinifera L.) buds cv. ;Perlette.' increased to a maximum in October and thereafter decreased within 3 months to less than half its maximal rate. The decrease in catalase activity coincided with the decline in temperature during winter. The rate of sprouting of buds forced at 23 degrees C was negatively related to the activity of catalase. Artificial chilling of grapevine canes at 5 degrees C resulted in a 25% decrease of catalase activity in the buds after 3 days and 31% after 17 days. The activity of catalase increased to the control level only 96 hours after removing canes from 5 degrees C to room temperature. Efficient buddormancy breaking agents, such as thiourea and cyanamide decreased catalase activity to 64 and 50% of the controls respectively, while the activity of peroxidase remained the same under those conditions. A less efficient dormancy breaking agent dinitro-ortho-cresol, did not decrease catalase activity.

Two lemon (Citrus × limon L. Burm. F.) cultivars, Eureka and Villafranca, were subjected to a mutation-inducing process, which led to the production of seedless mutants in both cultivars. This mutation-inducing process did not affect many other lemon traits.

The leaf macroelement profile of fruiting shoots of persimmon was characterized by a modified diagnostic and recommendation integrated system (DRIS), using SLW as a primary determinant of leaf mineral content. Leaf N, P, Ca, and Mg content was positively and linearly correlated with SLW when expressed on leaf area basis (p~g mm-2). Potassium had a negative and higher correlation to SLW when expressed on %DW basis. Mineral ratios relevant for the DRIS analysis were calculated using all four possible combinations of Area (A) and Weight (W) expressions (A/A, A/W, W/A and W/W) and correlated with leaf SLW. The particular expressions chosen for the DRIS analysis were based on their highest correlation to SLW and included N/K, P/K and Ca/Mg, based on the A / W expression of the respective nutrients and the reciprocal expression (W/A) for all other ratios. Derivation of DRIS norms were based on the mineral profile of highly exposed shoots (SLW of 15.0 + 0.3 mg cm-2). Calculated indices of gradually less exposed shoots (SLW of 3.8-18.9 mg cm -2) revealed a strong exponential imbalance of N, K and P (increasingly positive) vs Ca and Mg (increasingly negative). The calculated Nutritional Imbalance Index (NII) value of leaves decreased exponentially as shoot leaf SLW decreased. The modified DRIS analysis detected successfully a distinct mineral profile of highly vigorous fruiting 'water shoots', as compared to regular fruiting shoots of comparable SLW.

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Gibberellic acid (GA 3 ) is widely used to enlarge the berries of seedless grapes (Vitis vinifera L) . In cv . `Sultana' (Thompson Seedless) the addition of 1000 mg/L urea phosphate (UP) to GA 3 solutions after fruit set reduced the pH of the solutions to a stable pH 2 .9 and enhanced the effect of GA3 on berry size and delayed maturation . Addition of citrate buffer, pH 2.9, to GA3 sprays did not affect berry size or maturation . The possibility of improved GA penetration due to the low pH is considered . The nutritional effect of UP and direct enhanced penetration by the urea ion are also discussed.