Experiments were conducted to determine14C absorption, translocation, and metabolism by pitted morningglory (Ipomoea lacunosaL. # IPOLA) and ivyleaf morningglory [Ipomoea hederacea(L.) Jacq. # IPOHE] foliarly treated with14C-acifluorfen [5-(2-chloro-4-(trifluoromethyl)phenoxy)-2-nitrobenzoic acid] or14C-lactofen [(±)-2-ethoxy-1-methyl-2-oxoethyl-5-(2-chloro-4-(trifluoromethyl)phenoxy)-2-dinitrobenzoate]. Seventy-one to 84% of applied14C-acifluorfen was recovered in leaf water wash of ivyleaf morningglory compared to 32 to 46% from pitted morningglory. Sixty-four percent of applied14C-lactofen was recovered in leaf water wash 96 h after treatment in both morningglory species. Thirty-five to 37% more14C from applied14C-acifluorfen was found in pitted morningglory treated leaves than ivyleaf morningglory treated leaves. Less than 28% of applied14C-lactofen was extracted from treated leaves of either morningglory species. Translocation and metabolism of14C-acifluorfen and14C-lactofen were minimal in both morningglory species.

Summary Distichlis spicata, a salt marsh grass, sets dormant seeds which exhibit a low‐temperature, after‐ripening requirement. In addition to stratification, localized scarification and nitrate are effective agents in breaking dormancy and promoting seed germination. The pericarp and/or testa are impermeable to organic plant‐growth regulators, but not to water or inorganic salts. Gibberellic acid and kinetin are ineffective in breaking dormancy and do not affect germination. Abscisic acid, however, effectively inhibits stratified and scarified seeds. Dormancy and germination appear to be hormonally controlled. It is suggested that the endogenous inhibitor constitutes a block to nitrate reductase activity in the endosperm. Presumably the inhibitor blocks specific DNA transcription sites in the aleurone cells, but can be overcome by after‐ripening (inhibitor decay), abrasion (inhibitor leaching) or nitrate induction.

Peach tree [Prunus persica (L.) Batsch] short life, a disease complex resulting in premature death of peach trees, appears to be caused ultimately by cold injury to the vascular cambium. Indoleacetic acid (IAA) concentrations from the vascular cambium region of peach trees grown under various cultural practices were quantitated by thin-layer densitometry. Fall-pruned trees and trees in nonfumigated soil showed an elevated IAA level with respect to controls. It is suggested that early breaking of dormancy of the vascular cambium of peach trees, caused by an altered growth hormone balance, is responsible for the predisposition of certain trees to the cold injury death of peach tree short life.

1991 Investigations of proliferative and senescent callus of soybean. -Physiol Plant. 81: 513-517, Different expiant sources from several Glycine max (L,) Merr, cultivars and several G. soja F. J. Herm Piant Introductions were tested for calius production. Embryo axis explants produced callus most readily; hence, they were selected for media response studies and microscopic evaluation. Two callus types, proliferative and senescing, were identified and characterized hy light and scanning electron microscopy (SEM), Proliferative callus was composed of chloroplast-containing cells interspersed with colorless meristematic areas, while senescing callus contained mostly large, vacuoiate cells without chloroplasts. In SEM preparations a furry, layered, mucilaginous coating was seen on the outer surface of the senescing callus, while proliferative callus cells had uncoated, smooth or wrinkled surfaces. The mucilage contained glucose and galactose.

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