However, the schedule to follow and the best dosage have yet to be satisfactorily established.”
“Salinity limits

crop productivity, in part by decreasing shoot concentrations of the growth-promoting and senescence-delaying hormones cytokinins. Since constitutive cytokinin overproduction may have pleiotropic effects on plant development, two approaches Selleck Pexidartinib assessed whether specific root-localized transgenic IPT (a key enzyme for cytokinin biosynthesis) gene expression could substantially improve tomato plant growth and yield under salinity: transient root IPT induction (HSP70::IPT) and grafting wild-type (WT) shoots onto a constitutive IPT-expressing rootstock (WT/35S::IPT). Transient root IPT induction increased root, xylem sap, and leaf bioactive cytokinin concentrations 2- to 3-fold without shoot IPT gene expression. Although IPT induction reduced root biomass (by 15%) in control (non-salinized) plants, in salinized plants (100 mM NaCl for 22 d), increased cytokinin concentrations delayed stomatal closure and leaf senescence and almost doubled shoot growth (compared with WT plants), with concomitant increases in the essential nutrient K(+) (20%) and decreases in the toxic ion Na(+) (by 30%) and abscisic acid (by 20-40%) concentrations in transpiring mature leaves. Similarly, WT/35S::IPT plants (scion/rootstock) grown with 75 mM NaCl for 90 d had higher ML323 in vivo fruit trans-zeatin concentrations (1.5-

to 2-fold) and yielded 30% more than WT/non-transformed BAY 80-6946 mw plants. Enhancing root cytokinin synthesis modified both shoot hormonal and ionic status, thus ameliorating salinity-induced decreases in growth and yield.”
“To go ahead in understanding the nature of rubber reinforcement and evaluate the kinetics of filler clusters destruction during stretching of filled rubber, the styrene-butadiene rubber both unfilled and filled with various contents of silica particles with and without surface treatment was tested under quasistatic loading up to failure. The

Klueppel-Schramm model was used for description of strain softening, evaluation of both the rubber and filler network parameters as the functions of the filler volume content. It was found that an elastic modulus as a function of filler volume content follows Guth-Gold equation, confirming the hydrodynamic nature of the rubber reinforcement; the effectiveness factor depends on filler surface treatment. Hydrodynamic amplification factor increases with increase of filler volume content, its value depends on filler particles surface treatment. The decrease of hydrodynamic amplification factor during stretching correlates with the increase of viscoelastic strain. Taking into account the viscoelastic strain improves the description of the stress-strain response of filled rubber for loading-unloading process with the parameters obtained for active loading. (C) 2011 Wiley Periodicals, Inc.