Possible mechanism of gibberellin-induced chlorosis in lettuce seedlings

Abstract

Effects of gibberellin A3 (GA) on growth, pigments, protein, and nucleic acid content of the cotyledons of lettuce seedlings (Lactuca sativa L. cv. Grand Rapids) are reported. GA treatment increased both the total shoot and cotyledon fresh weights, and decreased chlorophyll content per cotyledon and on a dry weight basis. GA also decreased the protein content of the cotyledon, but increased the level of RNA and DNA measured on a dry weight basis. The hormone had no effect on the pheophytin: chlorophyll ratio, but increased the ratios of chlorophyll a: chlorophyll b, phytol: chlorophyll, and carotene: chlorophyll. GA also increased the sugar content of the cotyledons. Treatment of excised cotyledons with glucose had an effect similar to that of GA on chlorophyll and protein content. The data are discussed in relation to the mechanism of GA-induced chlorosis.

Characterization ofArabidopsis thalianaGCN2 kinase roles in seed germination and plant development

“…Our result is in agreement with the previous findings showing that a gibberellininsensitive gai mutant has higher chlorophyll contents 31,36 and exogenous application of GA leads to decreased chlorophyll contents and chlorosis. 37 This notion strengthens the hypothesis that AtGCN2 is implicated in the GA signaling pathway.…”

Control of the Light Saturation Point for Photosynthesis in Tomato

“…This change in chlorophyll a to b ratio along with the general reduction of chlorophyll content could be an indication of a reduction in the size of the photosynthetie unit. Das (1973) showed a decrease in chlorophyll and alteration of a to 6 ratio in lettuce following gibberellin treatment which was very similar to our data.…”

Influence of Essential Oils of some Medicinal and Aromatic Plants on Growth and Control of Botrytis fabae the Causal of Faba Bean Chocolate Spot

“…Also, the reduction in chlorophyll content of infected plants may be due to destructive effect of phytopathogens or their metabolites on chloroplasts (Hassan et al, 2006) or protein synthesis (Pundir et al, 1991). Such influence might subsequently lead to an inhibition in chlorophyll formation and chloroplast development (Das, 1973). Increasing photosynthetic pigments will expected to increase carbohydrate content in plant tissues.…”