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  • Author or Editor: K. Uriu x
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Chloride and boron toxicity symptoms and tissue concentrations were characterized and distinguished in kiwifruit. Dormant cane, bud, emerging leaves, blade and petiole samples were taken from February through October 1989 from three vineyards - a high chloride, a high boron and a low boron, low chloride control. Chloride toxicity symptoms started showing in early summer on basal leaves. By late summer, necrosis symptoms were on mid-shoot and leaves near the shoot terminal. In boron toxicity, interveinal chlorotic areas appeared first followed by marginal necrosis. Symptoms were seen on basal leaves in early spring, progressively affecting upper leaves by harvest. The high chloride vineyard accumulated chloride from early spring with the petiole concentrating more chloride than the blade. In the high boron vineyard, boron increased greatly in the blade but not in the petiole. Another sampling procedure other than mid-season leaf samples could be emerging leaves for detecting high chloride and dormant cane tips, buds or emerging leaves for high boron.

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Abstract

Concentrations of several mineral elements in leaflets of Pistacia vera L. cv. Kerman, did not differ significantly with leaflet position. Thus, leaflets may be used instead of whole leaves in leaf sampling. Analyses of leaflets indicated that N, P, and Zn concn were relatively high initially. They then dropped rapidly during leaf expansion, reaching a steady state in early summer. Manganese increased from an initially low level and then remained fairly constant. Potassium, Mg, Cl, and B behaved similarly to Mn, but reached constant levels later in the season. Leaves from bearing branches were lower in N and P, but higher in K than leaves from nonbearing branches. It is recommended, in determining mineral element status, that leaves from nonbearing branches be sampled during the month prior to harvest, as most elements are then at a steady state.

Open Access
Authors: and

Abstract

Radial trunk growth measured by the Verner dendrometer was reduced markedly due to competition for assimilates and water by greatly stimulated fruit growth resulting from the application of 2,4-D. These responses were accompanied by reduced water tension within the 2,4-D-treated trees, as indicated by less diurnal trunk shrinkage than that which occurred in control trees.

Open Access

Abstract

Water potential, diffusive resistance, and abscisic acid (ABA) were measured at 10-12 day intervals from May to October in leaves from irrigated and non-irrigated peach (Prunus persica L. cv. Fay Elberta) trees, and measurements were taken at intervals from sunrise to sunset on September 8. Leaf water potential, before sunrise, was between −5 and −8 bars in irrigated trees during the entire season whether drip irrigated at 100% evapotranspiration (ET) or 50% ET. Non-irrigated trees showed a decrease in pre-dawn leaf water potential with time, following a pattern similar to that of decreasing soil moisture. Leaf water potential values taken during the afternoon were not associated with soil moisture and did not reflect the stressed condition of the trees. In non-irrigated trees stomatal resistance at mid-day increased rapidly after mid-summer as leaf water potential decreased. ABA concentration in leaves from irrigated trees ranged from 30 to 80 ng/g fresh wt during the entire season. In non-irrigated trees the ABA concentration increased sharply after mid-summer; this was associated with an increase in leaf diffusive resistance and a decrease in leaf water potential. Diurnal variations in leaf water potential were associated with changes in soil moisture, air temperature, relative humidity, and stomatal resistance. Leaf diffusive resistances were similar for all treatments until 1100 hr after which a notable increase occurred with increasing stress, ultimately leading to stomatal closure. ABA concentrations in leaves from irrigated and non-irrigated trees increased as leaf diffusive resistance increased; however in stressed trees, high levels of ABA in the morning were not associated with closed stomata.

Open Access

Abstract

Withholding irrigation of walnut trees (Juglans regia L. cv. Ashley) for one growing season significantly reduced trunk growth and kernel weight. Tree survival and return cropping were unaffected. When irrigation was resumed kernel weight was significantly heavier than that from trees irrigated the previous year.

Open Access

Abstract

Fruit growth and final size were greater on lightly cropped than on moderately heavily cropped cherry (Prunus avium L. cv. Buriat) trees. A wax-based antitranspirant (AT), sprayed 1 week before harvest, increased fruit size on both lightly and moderately heavily cropped trees. Although the lightly cropped AT-treated trees had the largest fruit at harvest, the response to AT was greatest on the moderately heavily cropped trees. Thus, AT can improve fruit grade-size, and probably monetary returns, particularly on heavily cropped trees. High rates of AT application, however, can adversely affect fruit appearance.

Open Access

Abstract

An antitranspirant film was used as a research tool to determine which part of the sweet cherry (Prunus avium L.) fruit is the principal path for absorption of external water (rain). Antitranspirant applied to the entire fruit surface reduced water intake to half that of control fruit or fruit treated only on the top and/or bottom. A preliminary field trial investigated the film’s “rain-coating” effect as a possible means for reducing cherry cracking.

Open Access

Abstract

A firm-forming antitranspirant sprayed on trees of ‘Halford’ and ‘Vivian’ cling peach [Prunus persica (L.) Batsch] 1-2 weeks before harvest, increased fruit growth and substituted for a preharvest irrigation. Such replacement of the final irrigation can enable timely entry of harvest equipment to the orchard, unhampered by a wet soil surface, without a reduction in fruit growth.

Open Access

Abstract

Maleic hydrazide (MH) was readily translocated in the apricot tree, as indicated by inhibition of shoot growth and seed abortion in the fruits. However, cambial activity was undisturbed, and trunk growth proceeded normally.

Open Access

Abstract

A film-forming antitranspirant sprayed on trees of olive (Olea europa L. cv. Sevillano) increased equally the growth of bagged (to prevent spray contact) and unbagged fruit. Hence, enhanced fruit growth depends upon film formation on stomata-bearing leaf surfaces, rather than direct contact of fruit by the spray.

Open Access