Modifications of water status, growth rate and antioxidant system in two wheat cultivars as affected by salinity stress and salicylic acid.

Salicylic acid (SA) has an important role in drought-tolerance in wheat (Triticum aestivum L.) but its relevance to the salinity-tolerance is not well understood. In the present study, possible roles of SA and salinity responses were examined using two wheat cultivars i.

Uranium accumulation and its phytotoxicity symptoms in Pisum sativum L.

Environmental contamination by uranium (U) and other radionuclides is a serious problem worldwide, especially due to, e.g. mining activities.

Physiological changes of a green alga (Micractinium sp.) involved in an early-stage of association with Tetrahymena thermophila during 5-year microcosm culture.

Endosymbioses between phototrophic algae and heterotrophic organisms are an important symbiotic association in that this association connects photo- and heterotrophic metabolism, and therefore, affects energy/matter pathways and cycling in the ecosystem. However, little is known about the early processes of evolution of an endosymbiotic association between previously non-associated organisms. In previous studies, we analyzed an early process of the evolution of an endosymbiotic association between an alga and a ciliate by using a long-term culture of an experimental model ecosystem (CET microcosm) composed of a green alga (Micractinium sp.

Changes in the water status and osmotic solute contents in response to drought and salicylic acid treatments in four different cultivars of wheat (Triticum aestivum).

Salicylic acid (SA) controls growth and stress responses in plants. It also induces drought tolerance in plants. In this paper, four wheat (Triticum aestivum L.

Mannose accommodation of Vigna angularis cells on solid agar medium involves its possible conversion to sucrose mediated by enhanced phosphomannose isomerase activity.

Mannose is an unusable carbon source for many plants. In our study we compared the effects of mannose and sucrose on growth and sucrose levels in azuki bean (Vigna angularis) cells grown in liquid media and in solid media. The suspension cells grew actively in a liquid medium containing 90 mM sucrose but not in that containing 90 mM mannose, where the intracellular sucrose levels were reduced to 20% or less of those in sucrose-grown cells.

Different effects of galactose and mannose on cell proliferation and intracellular soluble sugar levels in Vigna angularis suspension cultures.

Plant cells utilize various sugars as carbon sources for growth, respiration and biosynthesis of cellular components. Suspension-cultured cells of azuki bean (Vigna angularis) proliferated actively in liquid growth medium containing 1% (w/v) sucrose, glucose, fructose, arabinose or xylose, but did not proliferate in medium containing galactose or mannose. These two latter sugars thus appeared distinct from other sugars used as growth substrates.

Copper extrusion after accumulation during growth of copper-tolerant yeast Yarrowia lipolytica.

The Cu2+-tolerant yeast Yarrowia lipolytica accumulated Cu2+ until the late logarithmic phase. Thereafter, Cu2+ was temperature-dependently extruded into phosphate-limited culture medium containing high concentrations of heavy metal ions but not into 10 mM 2-(N-morpholino)ethane sulfonic acid (MES) buffer (pH 6.0).

Effect of copper on acid phosphatase activity in yeast Yarrowia lipolytica.

Acid phosphatase (APase) activity of the yeast Yarrowia lipolytica increased with increasing Cu2+ concentrations in the medium. Furthermore, the enzyme in soluble form was stimulated in vitro by Cu2+, Co2+, Ni2+, Mn2+ and Mg2+ and inhibited by Ag+ and Cd2+. The most effective ion was Cu2+, especially for the enzyme from cultures in medium containing Cu2+, whereas APase activity in wall-bound fragments was only slightly activated by Cu2+.

Characteristics of copper tolerance in Yarrowia lipolytica.

We discovered that a mutant strain of the dimorphic yeast Yarrowia lipolytica could grow in the yeast form in high concentrations of copper sulfate. The amount of metal accumulated by Y. lipolytica increased with increasing copper concentrations in the medium.

Relief of arsenate toxicity by Cd-stimulated phytochelatin synthesis in the green alga Chlamydomonas reinhardtii.

In most photosynthetic organisms, inorganic arsenic taken up into the cells inhibits photosynthesis and cellular growth. In a green alga, Chlamydomonas reinhardtii, 0.5 mM arsenate inhibited photosynthesis almost completely within 30 min.

Changes in the levels of phytochelatins and related metal-binding peptides in chickpea seedlings exposed to arsenic and different heavy metal ions.

Phytochelatin-related peptides were analyzed in chickpea plants exposed to six different heavy-metal ions. Cadmium and arsenic stimulated phytochelatin and homophytochelatin synthesis in roots but other metals did not. These metals, however, caused an overall increase in the precursors, glutathione, homoglutathione and cysteine.

Possible roles of phytochelatins and glutathione metabolism in cadmium tolerance in chickpea roots.

The possible roles of phytochelatin (PC) and glutathione (GSH) in the heavy metal detoxification in plants were examined using two varieties (CSG-8962 and C-235) of chickpea ( Cicer arietinumL.). The seedlings were grown for 5 days and the roots were treated with 0-20 micro M CdSO(4) for 3 days.

Impacts of fly-ash on soil and plant responses.

Coal combustion produces carbon dioxides, SO x, NO x and a variety of byproducts, including fly-ash, flue gas and scrubber sludge. Fly-ash consists of minute glass-like particles and its deposition on leaves inhibits the normal transpiration and photosynthesis of plants. Fly-ash also affects the physicochemical characteristics of soil because it is generally very basic, rich in various essential and non-essential elements, but poor in both nitrogen and available phosphorus.