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- Author or Editor: A. H. Hatch x
- Journal of the American Society for Horticultural Science x
Abstract
Studies were conducted to determine the effect that plant hormones such as auxins, gibberellins, and cytokinins might have on the mobilization of 32P in apple seedlings grown in the greenhouse. Prior to the hormone treatments the seedlings were defoliated and the apex removed to avoid competition. Experiments with 32P indicated that auxins, gibberellins, and cytokinins could direct the transport of 32P especially when used in various mixtures. It was found that 32P could be mobilized acropetally, basipetally, and into and out of leaves depending on the area treated with the hormones. Their effect in mobilizing 32P was less evident in seedlings that had ceased growth, with subsequent terminal bud formation, than in growing seedlings. It was also found that 32P was mobilized through the phloem and required the synthesis of protein.
Abstract
Indoleacetic acid (IAA), gibberellins A4 + A7 (GA4&7) and benzyladenine (BA) were applied to apple seedlings to determine their influence on movement or translocation of 14C-sorbitol, 14C-glycine, 14C-naphthaleneacetic acid (14C-NAA), 3H-gibberellin A1 (3H-GA), and 14C-kinetin. The materials mobilized 14C-sorbitol in an acropetal direction, but only after root competition had been eliminated by steam girdling. A mixture of the 3 growth substances brought about mobilization of 14C-glycine acropetally that was greatly enhanced after root competition had been eliminated. 14C-NAA was not mobilized acropetally or basipetally by GA4&7, and/or BA. BA mobilized 3H-GA1 acropetally and mobilization was enhanced by the addition of IAA. A mixture of IAA and BA also mobilized 3H-GA1 basipetally. An acropetal movement of 14C-kinetin was induced only with a mixture of GA4&7 and IAA.
Abstract
Radioactive (2-chloroethyl)phosphonic acid (ethephon) was applied to leaf and fruit surfaces 6 to 10 days before normal harvest date. Samples were collected periodically following application and analyzed with appropriate extraction and counting procedures. The level of radioactive ethephon increased in the fruit for about 48 to 72 hr, then decreased to a low level after 6 days. No intermediate metabolites were detected in the fruits. It was found that the majority of the ethephon in the fruits moved there from the application on adjacent leaves; relatively small amounts moved directly into the fruit from surface application. Radioactive ethylene was detected within 12 hr after application of the 14C-ethephon on the leaf surfaces.