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Abstract
The growth retardant N-dimethyl amino succinamic acid (Alar) has been reported to retard fruit tree growth and induce repeat bloom (1,3). It increases surface color and firmness of apples, decreases their size and susceptibility to scald, and slightly decreases their soluble solids content (1,5). Recently Alar has been reported to reduce water core and pre-harvest drop (2). Some of these effects are suggestive of delayed maturity while others are not. The study reported here was conducted to determine the effects of Alar on fruit maturity of Delicious apples when applied two weeks after full bloom.
Abstract
Alar applied at the rate of 4000 ppm to ‘Delicious’ apple trees in the fall delayed bloom the following spring four to five days and increased fruit set. At harvest, the fruits were smaller, less elongated, had more advanced ground color and expressible juice. Fruit diameter, over color, flesh color, soluble solids, and respiration rate were not affected.
Abstract
Six stages of floral development were identified and related to air temperature in Carya illinoensis (Wang.) K. Koch, cv. Western. Initiation (the first microscopically visible evidence of floral primordia) was detected on April 4, 1973, after an accumulation of 537 heat units. On April 10 a total of 598 heat units were accumulated when 93% of the buds sampled had initiated pistillate flowers. Floral development occurred normally, uniformly, and in concert with the heat units accumulated.
Potted `Chardonnay' grapevines (Vitis vinifera L.) with either two or three shoots were grown in a greenhouse for one month and then transferred to a phytotron room, where either one or two shoots were shaded. Twenty-four days after transfer, leaves at the fifth node of either the light-adapted or shade-adapted shoot were exposed to a 2-hour pulse of 14CO2. Both light environment and number of shade shoots on the vine had a significant effect on photosynthate partitioning within the plant following a 22-hour chase. Leaves fed with 14CO2 on a light-adapted shoot translocated 26.1% and 12.7% more radioactivity to the roots and trunk, respectively, than leaves from shade-adapted shoots. Photosynthates were exported from light-adapted leaves to shade-adapted shoots (1.3% of total 14C in plant). The number of shaded shoots and the light environment of the fed leaf had a large effect on partitioning of photosynthates among ethanol-insoluble, water-soluble, and chloroform-soluble fractions within the leaf. Recovered 14C in the water-soluble fraction of the fed leaf appeared to be affected more by number of shoots than by light environment of the fed leaf. The data suggest that there is a sink effect on initial carbon partitioning patterns in grapevine leaves. Sink strength may have a greater role than light environment. A large proportion of interior leaves versus exterior leaves may be costly with respect to the carbohydrate budget of a vine.