Reduced nutrient uptake in peach trees with paclobutrazol

ISHS Acta Horticulturae 463: VIII International Symposium on Plant Bioregulation in Fruit Production. 6 Pag., 4 Tabl. The definitive version is available at: http://www.actahort.org/Paclobutrazol (Pbz) is a triazol that effectively inhibits vegetative growth in peach. Changes in mineral element concentration have been generally found. However, uneven distribution of the elements in the soil may partially account for these differences. The trees were treated with 2 g Pbz/tree shortly AFB. Reductions of 40% in leaf area and of 29% in dry weight were recorded in Pbz-treated peach. Nutrient concentration on dry weight basis varied little (about 11%). However, global assimilation of nutrients on a leaf basis, when compared with controls, decreased up to the same extend as dry weight (25%). From these results it can be inferred that the mineral fertilization in Pbz-treated peach trees can be reduced to the same extend as the expected reduction in vegetative growth, consequently reducing production costs and environmental contamination.Peer reviewe

Effect of iron chlorosis on mineral nutrition and lipid composition of thylakoid biomembrane in Prunus persica (L.) Bastch

The effect of iron chlorosis on mineral, thylakoid lipids and fatty acids composition of field grown peach tree leaves was studied. Significant differences were found in iron extracted by using α, α′-dipyridyl (active iron), total iron, P, K, Cu and the P/Fe and Fe/Mn ratios. The levels of total chlorophyll, total glycolipids and phospholipids were reduced under iron chlorosis. A slight iron deficiency does not modify the fatty acid composition of thylakoid membranes, while a strong deficiency changes the proportion of some fatty acids.Work was carriedout under the following research projects CICYT AGR90-0792 and CONAI-DGA: PCA-4/91.Peer Reviewe

Crop-load effects on vegetative growth, mineral nutrient concentration and leaf water potential in Catherine' peach

Variations of crop-load in the peach (Prunus persica (L.) Batsch.) cv. Catherine by thinning the fruitlets at petal fall affected fruit and vegetative growth of trees. Shoot length, and fresh and dry weight decreased exponentially as the cropping level increased, while the relative increment in trunk girth decreased linearly. Yield increased following a quadratic pattern, while fruit size, measured as mean fruit weight, decreased exponentially as the crop load increased. Mineral element analysis in leaves has shown that Mn concentration decreased linearly with increasing numbers of fruits borne by the tree, both before and after harvest, while the other elements analysed (P, K, Ca, Mg, Fe, Cu, and Zn) did not show any variation. Leaf water potential during the time of fruit growth also decreased exponentially as the crop-load increased.Peer reviewe