Silicon (Si) has been known to augment plant defense against biotic and abiotic pressures. Maize (Zea maize L.) is classified as a Si accumulator and is relatively susceptible to alkaline stress. In this study, seeds of maize were grown in pots and exposed to various concentrations of Na2CO3 (0, 25, 50, and 75 mM) with or without 1.5 mM Si in the form of sodium metasilicate Na2O3Si.5H2O for 25 ...

Cellular Na(+)/K(+) ratio is a crucial parameter determining plant salinity stress resistance. We tested the function of plasma membrane Na(+)/K(+) cotransporters in the High-affinity K(+) Transporter (HKT) family from the halophytic Arabidopsis (Arabidopsis thaliana) relative Thellungiella salsuginea. T. salsuginea contains at least two HKT genes. TsHKT1;1 is expressed at very low levels, whil...

Blood-tissue transport of 42 K, 8a Rb, and 22 Na was studied in perfused gracilis muscles of dogs to ascertain the influence of capillary wall, interstitial space, and muscle cell membranes on overall transport kinetics. Single-injection and continuous-infusion techniques were used, with T-1824 or 51 Cr-hemoglobin as nondiffusible references. Results were as follows: (1) Extraction (E) of the d...

Understanding mechanisms of salt tolerance, physiological responses to salt stress, and screening genotypes for breeding programs are important scientific issues remained to be investigated in pistachio. Therefore, current study was carried out to investigate response of different pistachio cultivars (G1, G2, Kaleghochi and UCB1) to salinity treatments (0.6 as control, 10, 20 dS m-1 using salin...

Ionic stress is one of the most important components of salinity and is brought about by excess Na+ accumulation, especially in the aerial parts of plants. Since Na+ interferes with K+ homeostasis, and especially given its involvement in numerous metabolic processes, maintaining a balanced cytosolic Na+/K+ ratio has become a key salinity tolerance mechanism. Achieving this homeostatic balance r...

To study the size and structure of the Na,K-pump molecule, the ultrastructure of phospholipid vesicles was examined after incorporation of purified Na,K-ATPase which catalyzes active coupled transport of Na+ and K+ in a ratio close to 3Na/2K. The vesicles were analyzed by thin sectioning and freeze-fracture electron microscopy after reconstitution with different ratios of Na,K-ATPase protein to...

Na(+)/K(+)-ATPase (sodium pump) is an important target for the development of botanical pesticide as it is responsible for transforming chemical energy in ATP to osmotic work and maintaining electrochemical Na(+ )and K(+ )gradients across the cell membrane of most animal cells. Celangulin IV (C-IV) and V (C-V), which are isolated from the root bark of Celastrus angulatus, are the major active i...

Epinephrine and amylin stimulate glycogenolysis, glycolysis, and Na+-K+-ATPase activity in skeletal muscle. However, it is not known whether these hormones stimulate glycolytic ATP production that is specifically coupled to ATP consumption by the Na+-K+pump. These studies correlated glycolysis with Na+-K+-ATPase activity in resting rat extensor digitorum longus and soleus muscles incubated at 3...

Soil salinity is a major abiotic stress that results in considerable crop yield losses worldwide. However, some plant genotypes show a high tolerance to soil salinity, as they manage to maintain a high K+/Na+ ratio in the cytosol, in contrast to salt stress susceptible genotypes. Although, different plant genotypes show different salt tolerance mechanisms, they all rely on the regulation and fu...

Vesicles containing a purified shark rectal gland (sodium + potassium)-activated adenosine triphosphatase-(NaK ATPase) were prepared by dialyzing for 2 days egg lecithin, cholate, and the NaK ATPase purified from the rectal gland of Squalus acanthias. These vesicles were capable of both Na+ and K+ transport. Studies of K+ transport were made by measuring the ATP-stimulated transport outward of ...