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  • Author or Editor: George C. Martin x
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Abstract

‘Bartlett’ pear trees were sprayed 2 weeks after full bloom or 4 weeks before harvest with a single application of succinic acid 2,2-dimethylhydrazide (Alar) at 1,000 or 2,000 ppm. Some trees that received 1,000 ppm were given a second application of Alar at 1,000 ppm 3 weeks after full bloom or 3 weeks before harvest. Alar was as effective as NAA at 10 ppm in preventing preharvest drop of fruits. Alar applied as a double spray early in the season or as a single or double spray late in the season was equally effective. Use of Alar as a preharvest drop spray provides great flexibility as it can be applied over a wide range of time. No undesirable side effects were noted from the use of Alar.

Open Access
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Abstract

In a study of the purity and stability of 1,2-14C(2-chloroethyl)phosphonic acid when used as a radioactive tracer, 3 out of 4 radioactive impurities detected were found in all standards tested. In addition, 7 other non-radioactive compounds were found in 1 of the 14C-CEPA standards. One contaminant was found to be in equilibrium with the 14C-CEPA. No contaminants were detected on GLC of the non-radioactive CEPA standard. 14C-CEPA was non-enzymatically bound to some constituents in extracts of peach fruits, cv. Halford, particularly to sugars.

Open Access

Abstract

A method is described for the rapid determination of percent water in walnut seed by use of near-infrared spectrophotometry.

Open Access

Abstract

In two consecutive growing seasons, extracts of prune flower and fruit tissue were bioassayed for hormonal activity. High levels of GA-like and neutral auxin-like compounds were evident in seed extracts in midseason during the period of rapid embryonic growth. An ABA-like inhibitor increased in the pericarp as maturity approached, while GA-like activity fell to negligible levels.

Open Access

Abstract

Concentration of abscisic acid (ABA), abscisic acid-glucose ester (ABA-GE), indoleacetic acid (IAA), zeatin (Z), zeatin riboside (ZR) and gibberellic acid (GA) were measured in ‘Winter Nebs’ pear (Pyrus communis L.) receptacles from anthesis to 12 days thereafter. Concentration of GA or IAA may signal subsequent growth rate for GA3-treated and pollinated receptacles. No correlations with growth were evident for Z or ZR. ABA-GE began massive accumulation prior to the senescence and abscission of control receptacles.

Open Access

Abstract

On 9 Mar. 1859, Alfred Russel Wallace dispatched a manuscript to Charles Darwin from the remote island of Ternate in the Moluccas. With his paper on species divergence, the young naturalist sent a request that, if the paper were judged to have merit, it should be passed on to Sir Charles Lyell, a leader in the English scientific establishment. When the paper arrived on 18 June, Darwin read it with dismay and distress (he had been preempted), but sent it the same day to Lyell, who also showed it to botanist Sir Joseph Dalton Hooker. The paper was read at the meeting of the Linnean Society of 1 July (along with some material of Darwin's) and appeared in print in the Journal of the Linnean Society the following month. Thus, 128 years ago, in the days of sailing ships and handset type, a manuscript sent from an obscure corner of the world took less than 6 months from manuscript to print and less than 3 months after arrival in England.

Open Access

Abstract

The influence of temperature on the growth and development of deciduous tree fruits has been inadequately investigated. In most cases only general field observations have been reported. The temperature conditions prior to and during such general observations are variable and cannnot be repeated precisely. To control temperature, limb sleeves and small chambers have been used to cover portions of limbs (2,3). Information from such devices is of limited value since they do not preclude the influence of the rest of the tree.

Open Access

Abstract

CGA-15281 was tested using an in vitro laboratory system with fruit-bearing shoots of ‘Manzanillo’ olive (Olea europeae L.). Foliar sprays produced greater fruit abscission and lower leaf abscission than stem feeding. Maximal fruit abscission with the least leaf abscission occurred at a concentration of 600 ppm, 23 to 25°C, and pH 7.

Open Access

Abstract

A nondestructive system for measuring volatile compounds, specifically ethylene, evolved from intact fruit of olive (Olea europaea L.) in the field is described. Polyethylene cans from 35-mm film cartridges are modified with a rubber septum for sampling. The lid is sealed around the fruit peduncle and remains in the field under all conditions. The can is removable to expose the fruit to normal conditions when sampling is not being done. Samples of the atmosphere inside the can are taken with a syringe for gas chromatographic analysis. Background ethylene evolution from the system is low. The system allows repeated monitoring of the same fruit over the duration of a season. Nineteen glues and sealants are evaluated for bonding, phytotoxicity, and ethylene evolution.

Open Access

Abstract

Foliar spraying the same French prune trees with 50, 100, or 150 ppm (2-chloroethyl) phosphonic acid (ethephon) in 3 continuous years thinned fruit and improved fruit size without deleterious phytotoxic effects on tree performance.

Open Access