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  • Author or Editor: John Sacalis x
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It has previously been demonstrated that exceedingly high concentrations of 2,4-D, when taken up by cut carnations, inhibit petal senescence, while application of low concentrations of this synthetic auxin promote petal senescence. The mode of action of such high concentrations of 2,4-D has not been elucidated.

In previous work, it was observed that significant amounts of volatiles always emanated from those flowers treated with high 2,4-D, and which displayed inhibition of ethylene synthesis as well as petal senescence. In the present work, the headspace of treated flowers was therefore tested by gas chromatography after enclosure for a short period of time. Two of the major constituents of the volatiles produced by the treated flowers were found to be ethanol and acetaldehyde.

Since ethanol has formerly been shown to delay senescence in carnation flowers, and since 2,4-D has been shown to induce alcohol dehydrogenase, it is suggested that the mode of action of 2,4-D in this case is by means of the ethanol produced as a result of the 2,4-D treatment.

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Abstract

Treatement of cut roses with sugers such as surcose appreciably extends their postharvest life. Sucrose serves as a metabolic energy source, but it is probable that sucrose may play additional roles in restricing the loss of water from floral tissue.

Open Access

Abstract

Ethylene evolution from callus tissue of rose (Rosa hybrida L.) grown in air tight vessels was enhanced by the presence of auxin and cytokinin in the culture medium. Increased ethylene levels did not adversely affect the fresh weight gain of rose callus tissue.

Open Access

Abstract

Cut roses (Rosa hybrida L. cv. White Butterfly) pulsed with 14C-sucrose were analyzed for changes in total and labeled sucrose, glucose, fructose and starch after chases of various periods in either water or sucrose solution. Changes of 14C in an ethanol-insoluble fraction defined as the “cell wall fraction” were also studied. Changes in total amounts of each sugar did not correspond to changes in their respective labeled sugars, and these dissimilariteis in pattern indicated rapid turnover of each sugar in stems, and moderate turnover in leaves, with a general movement of 14C out of both leaves and stems. In flower heads, there was an initially short, overall incorporation of labeled sugars, followed by a gradual increase of 14C-glucose and 14C-fructose, but not 14C-sucrose. Starch turnover was appreciable in flower heads and in leaves, but not in stems. The leaves of roses held in the water chase showed the greatest turnover of starch. Incorporation of 14C into that portion of the ethanol-insoluble fraction designated “cell wall fraction” was greater in flower heads of roses chased in sucrose than those chased in water, but the type of chase solution used had little effect on incorporation of 14C into the “cell wall fraction” of leaf and stem tissue.

Open Access

Abstract

14C-sucrose, when taken up into the xylem, moved rapidly into leaves and flower heads of cut roses (Rosa hybrida L.) Outward lateral movement of 14C occurred rapidly along the entire length of stem at a uniform rate, regardless of l4C-sucrose concentration within the xylem and associated tissues. The quantity of 14C inverted sugars found in xylem tissue after uptake of 14C sucrose, and the rapid hydrolysis of sucrose passing through xylem of isolated stem segments suggests the involvement of invertase located in the xylem.

Open Access

Abstract

Labeling patterns of absorbed 14C sugars in petal discs of ‘Forever Yours’ rose (Rosa hybrida L.) revealed that most of the sucrose was absorbed undegraded indicating that inversion was not a prerequisite for absorption of sucrose by petal tissue.

Open Access
Authors: and

Abstract

Studies were conducted to determine the involvement of ACC movement from extrapetal portions with initiation of petal senescence. During early senescence, ACC in all portions except the calyx displayed transient increases in levels of ACC. The largest increase in ACC specific concentration occurred in the receptacle. Removal of petals at harvest resulted in accumulation of ACC in the ovary and receptacle. [14C]ACC applied to the styles moved to the petals within 24 hr, but during this time, very little 14C was found in the receptacle. Although the major rise in ACC occurred in styles, ovary, receptacle, and petals between days 6 and 10 of aging, a secondary transient peak of ACC was always observed between days 2 and 4 only in the receptacle. It is suggested that the receptacle may contribute significantly to the initiation of petal senescence by acting as a source of ACC. Chemical names used: 1-aminocyclopropane-1-carboxylic acid (ACC).

Open Access

Abstract

In the paper by John N. Sacalis and Dominic Durkin, J. Amer. Soc. Hort. Sci. 97(4):481-484, 1972, an erroneous list of numbers was given in Table 3 (on page 484) to represent radioactivity in c.p.m. The corrected Table appears below, and can be clipped and pasted over Table 3 in Vol. 97(4):484.

Open Access

Abstract

Movement of 14C was studied in cut roses and carnations using a pulse of 14C-sucrose and a distilled water chase. The label moved selectively to leaves and stems, but not to flower heads during the pulse. During the chase, however, 14C moved from leaves and stems into the flower heads. Age had no effect on this movement into rose flower heads, but movement of 14C into carnation flower heads diminished as cut carnations aged.

It was established by girdling cut rose stems that assimilates are translocated from leaves and stems to flower heads via the phloem.

Open Access

Abstract

Respiration of petal discs from rose (Rosa hybrida L.) was measured by standard manometric techniques gave evidence for the presence of cyanide-resistant respiration. During early stages of rose petal expansion oxygen uptake by petal discs was only slightly inhibited by ImM KCN. In conjunction with 10−1mM salicyl hydroxamic Acid (SHAM), an inhibitor specific for the alternate cyanide-resistant pathway, 1mM KCN greatly reduced oxygen uptake in these petal discs. SHAM alone had no effect on petal disc respiration.

Open Access