24-epibrassinolide effects on in vitro callus tissue formation,growth, and regeneration in wheat varieties with contrasting drought resistance

Effects were investigated of kinetin replacement on 24-epibrassinolide (24-EB) in the in vitro cultured embryonic explants that were obtained from two varieties of spring soft wheat (Triticum aestivum L.)— Bashkirskaya 26 (drought resistant) and Salavat Yulaev (weakly resistant), differing in drought resistance, on the calli formation, its growth indices, contents of ABA and cytokinins, morphological and histological parameters, as well as their regenerative capacity. The resistant Bashkirskaya 26 variety, in contrast to the Salavat Yulaev variety, was characterized by a significantly higher frequency of calli formation in the culture of immature embryos on the 24-EB induction medium, higher increase in fresh and dry weights, and a large number of morphogenetic centers. On the medium containing kinetin, the Salavat Yulaev calli were characterized by an increased level of ABA throughout the experiment with a maximum of 15–25 days, whereas, in the Bashkirskaya 26 calli, the maximum ABA accumulation occurred on the seventh to 11th day of cultivation, after which a decrease in the hormone content was observed. It was found that calli of both varieties cultivated on the 24-EB medium against the background of absence in the ABA content changes were characterized by an increased content of endogenous cytokinins, especially significant in Bashkirskaya 26 calli. Calli of both varieties were characterized by a high regenerative capacity in all the studied variants of the regeneration medium. At the same time, the maximum capacity for regeneration and formation of regenerants with a single callus were revealed by replacing kinetin with 24-EB, especially pronounced in a resistant variety. The combination of the results obtained demonstrates the efficacy of 24-EB introducing instead of kinetin into the in vitro culture medium for explants of two varieties of spring soft wheat that differ in drought resistance, as evidenced by an increase in the frequency of callus formation from immature embryos, as well as the number of morphogenetic centers in the resulting calli.     

The involvement of wheat and common bean lectins in the control of cell division in the root apical meristems of various plant species

The effects of wheat germ agglutinin (WGA) and phytohemagglutinin (PHA) at the concentration of 1 mg/l on the rate of cell division in the root apical meristem of wheat (Triticum aestivum L.), barley (Hordeum vulgare L.), rice (Oryza sativa L.), and common bean (Phaseolus vulgaris L.) seedlings were compared. WGA enhanced cell division in the roots of barley and rice approximately similarly as in wheat roots but did not affect division of meristematic cells in the roots of common bean seedlings. In contrast PGA enhanced mitotic activity in the root apical meristem of common bean seedlings but did not affect division in the wheat and barley roots. Seedling treatment with lectins shifted the hormonal balance in them toward accumulation of growth activators (IAA and cytokinins). The relationship between lectin and hormonal systems in the control of cell division is discussed.     

Interaction between Signal Pathways upon Formation of Plant Defense in Response to Environmental Stress Factors

Russian Journal of Plant Physiology - In the course of evolution, plants have developed numerous specific regulatory signal pathways, which are hormonal for the most part. Phytohormones comprise...     

Lectin involvement in the development of wheat tolerance to cadmium toxicity

In the roots of bread wheat (Triticum aestivum L.) seedlings, the effects of pretreatment with 28 nM wheat germ agglutinin (WGA) and successive action of 1 mM cadmium acetate on growth, phytohormone balance, lignin deposition, and also cadmium accumulation and distribution were studied. Priority data on cadmium-induced ABA-mediated reversible accumulation of WGA in the roots, which was accompanied by its excretion in the medium of seedling incubation, were obtained. Pretreatment with WGA exerted a clear protective effect on seedling growth in the presence of cadmium, which was based on a decrease in the amplitude of stress-induced shifts in the balance between IAA and ABA and preventing the reduction in the cytokinin level. Acceleration of lignification of the cell walls in the basal parts of roots of seedlings pretreated with WGA and subjected to stress is shown, and this limits cadmium entry into the plant.