Changes in the degree of fatty acid (FA) desaturation are implicated plant responses to various abiotic stresses, including heat, salt and drought. However, it is still not known whether decreased levels linolenic acid, found many plants subjected drought stress, reflect a mechanism defence or damage. We addressed this question by generating tobacco cells ectopically overexpressing two FA desaturases: cytosolic FAD3 plastidic FAD8. A remarkable increase ratio total linoleic acids resulted...

A NaCl-tolerant cell line which was selected from ovular callus of ;Shamouti' orange (Citrus sinensis L. Osbeck) proved to be a true variant. This conclusion is based on the following observations. (a) Cells have been removed selection pressure for at least four passages retain same NaCl tolerance as do cells are kept constantly 0.2 molar NaCl. (b) Na(+) and Cl(-) uptake considerably lower in salt-tolerant (R-10) than salt-sensitive (L-5) given external concentration. (c) Growth markedly...

Shamouti orange (Citrus sinensis L. Osbeck) salt-tolerant cells were grown under low water potential conditions induced by polyethylene glycol (PEG), NaCl, and CaCl(2). On the basis of equal osmotic potentials, PEG was least inhibitory, NaCl next, CaCl(2) most inhibitory. The relation between growth capacity ion content can be summarized as follows. (a) Internal K(+) concentration a major factor which changed in presence PEG, probably played key role determining capacity. (b) concentrations...

The transfer of the glucosyl moiety from uridine diphosphate glucose in presence Acetobacter xylinum cell-free extracts led to formation a mixture alkali-soluble and -insoluble cellodextrins. Typical cellulose fibrils could not be detected by electron microscopy this product. Immediately after release into medium, formed whole cells is "prefibrous" form which passes through Millipore filters 0.45 0.8 micro pore diameter. Non-filtrable arise material probably process crystallization involving...

A protein whose level is markedly increased upon exposure of cultured citrus cells and whole plants to NaCl, was shown specifically catalyze the reduction phosphatidylcholine hydroperoxide in presence glutathione. This enzymatic activity be independent a similar exhibited by glutathione S-transferase plants. finding corroborates significant homology (52%) accounted between deduced amino acid sequence gene encoding for this that mammalian phospholipid peroxidases. While enzyme known well...

Abstract Several genes encoding putative glutathione peroxidase have been isolated from a variety of plants, all which show the highest homology to phospholipid hydroperoxide isoform. observations suggest that proteins are involved in biotic and abiotic stress responses. Previous studies on regulation gpx1, Citrus sinensis gene isoform, led conclusion salt-induced expression gpx1 transcript its encoded protein is mediated by oxidative stress. In this paper, we describe induction...

Salt-tolerant selected cells of Shamouti orange (Citrus sinensis) and Sour aurantium) grew considerably better than nonselected at any NaCl concentration tested up to 200 millimolar. Also, the growth response each treatment was identical in two species. However, performance species under osmotic stress induced by polyethylene glycol (PEG), which is presumably a nonabsorbed osmoticum, significantly different. The cell lines were more sensitive cells. salt adapted apparently also PEG. In...

Four selected NaCl-tolerant cell lines of Sour orange (Citrus aurantium) were compared with the nonselected line in their growth and internal ion content Na+, K+, Cl− when exposed to increasing NaCl concentrations. No difference was found among various Na+ uptake, all these took up similar or even larger amounts than NaCl-sensitive line. Exposure cells equal external concentrations NaCl, resulted a greater loss K+ from This observation leads conclusion that ability retain high levels are...

Abstract— Several recent reports indicate that the photosynthetic machinery possesses a device whereby relative distribution of absorbed light energy into two reaction centers can be varied in response to environment which photosynthesizing cells or chloro‐plasts are placed. Conditions reported affect this include electron acceptor donor system employed, concentration magnesium ions, and preillumination history preparation. These observations described discussed terms their relevance...

1 Ascorbate is concluded to serve as an electron donor at a site which prior photosystem 2. This conclusion supported by the following observations: Addition of ascorbate doubled apparent rate oxygen uptake in presence diquat. NADP+ photoreduction was not affected addition ascorbate, while concomitant evolution markedly inhibited. Both these reactions were sensitive 3-(3,4-dichlorophenol)-1,1-dimethylurea normal Hill reaction. shawed red-drop phenomenon ascorbate. 2 did two either heat-or...