Search Results

You are looking at 1 - 2 of 2 items for

  • Author or Editor: D. M. Krauskopf x
Clear All Modify Search

Abstract

Chemical growth retardants (2-chloroethyl)trimethylammonium chloride (chlormequat), succinic acid-2,2-dimethylhydrazide (SADH, daminozide) and α-cyclopropyl-α-(ρ-methoxyphenyl)-5-pyrimidinemethanol (ancymidol) were tested on Reiger Elatior begonia ‘Schwabenland Red’ (Begonia × hiemalis Fotsch). Chlormequat applied as a spray of 0.30% active ingredient (a.i.) (1:40 dilution of commercial product) caused height retardation in high and low light periods, being most effective in the winter. A 0.30% drench was excessive under low light conditions whereas both 0.30 and 0.60% drenches were ineffective under high light conditions. No significant height retardation was found when SADH was applied as a spray at concentration up to 0.50% a.i. Ancymidol was effective as a drench at 0.125 mg per 15 cm pot under both high and low light conditions. Ancymidol sprays at concentrations up to 33 ppm were ineffective.

Open Access

Abstract

The ionic Ca content of expressed apple juice conceivably could be used to estimate the total calcium content of fruit flesh. To evaluate this method, samples of 2 strains of ‘Delicious’ apple (Malus domestica Borkh.) were analyzed at 2- to 3-week intervals, from 4 weeks after full-bloom until full-maturity. Ionic Ca in the juice (juice Ca) was analyzed with a selective electrode, total Ca in the flesh (flesh Ca) with a plasma emission spectrophotometer. The correlation coefficient between calcium concentration in flesh vs. juice was very low during the early stages of fruit development, but increased to +0.758 (significant at P<0.0l) for samples collected 5, 3, and 0 weeks prior to fruit maturity. The correlation was generally significant at P<0.01 when all sampling dates were used (r = 0.734 for ‘Miller Spur’, +0.928 for ‘Starking’, and +0.831 for both strains). The calcium concentration in juice samples taken within 35 days of physiological fruit maturity paralleled the calcium concentration in the flesh on any given date, but was not a reliable predictor of flesh Ca concentration in fruit harvested 2 to 3 weeks thereafter.

Open Access