ABSTRACT
Being a universal reducing agent nicotinamide adenine dinucleotide phosphate hydrogen (NADPH) plays an important role in the cellular metabolism and the implementation of anti-stress reactions in plants. There are only a few enzymes that ensure the NADPH pool formation in cells. Among them, the most important are glucose-6-phosphate dehydrogenase (G6PDH, EC 1.1.1.49), malate dehydrogenase decarboxylating (DMDH, malic enzyme, EC 1.1.1.40) and NADP-isocitrate dehydrogenase (NADP-IDH, EC 1.1.1.42). The presented investigation is devoted to studying the influence of the individual and combinative effects of NaCl and γ-radiation as abiotic stress factors on biometric indicators and activity of these NADPH-generating enzymes, on organic content, and the formation of paramagnetic centers as defense reaction in corn (Zagatala-68 genotype) sprouts. It was found that 100 mM NaCl had an inhibitory effect on the development of sprouts. Relatively lower doses (50 Gy and 100 Gy) of γ-radiation had a positive, but its higher doses (150 Gy and 200 Gy) had a negative effect on this process. 500 Gy was a lethal dose (LD) for the corn sprouts. Combinative stress in all cases considerably delayed the development of sprouts. G6PDH showed the highest activity in the first, whereas, NADP-IDH showed the same activity in the last days of the experiment. All three enzymes, especially the G6PDH, have been activated in both root and stem tissues under the influence of stress factors (either radiation or salt). Combinative stress (γ-radiation + salt) also led to an induction of these activities which was necessary to neutralize the negative consequences of stress factors. Stress factors in all cases also had a negative effect on the content of organic matter in seedlings. Ionizing gamma radiation, which resulted in the formation of new paramagnetic centers as an anti-stress defense reaction in many cases was observed in wheat seedlings, but not in corn sprouts, which clearly shows that there are some differences in the protective mechanisms of these C3- and C4-types of plants to γ-radiation.
ABSTRACT
A single crystalline layered semiconductor In1.2Ga0.8S3 phase was grown, and by intercalating p-aminopyridine (NH2-C5H4N or p-AP) molecules into this crystal, a new intercalation compound, In1.2Ga0.8S3·0.5(NH2-C5H4N), was synthesized. Further, by substituting p-AP molecules with p-ethylenediamine (NH2-CH2-CH2-NH2 or p-EDA) in this intercalation compound, another new intercalated compound-In1.2Ga0.8S3·0.5(NH2-CH2-CH2-NH2) was synthesized. It was found that the single crystallinity of the initial In1.2Ga0.8S3 samples was retained after their intercalation despite a strong deterioration in quality. The thermal peculiarities of both the intercalation and deintercalation of the title crystal were determined. Furthermore, the unit cell parameters of the intercalation compounds were determined from X-ray diffraction data (XRD). It was found that increasing the c parameter corresponded to the dimension of the intercalated molecule. In addition to the intercalation phases' experimental characterization, the lattice dynamical properties and the electronic and bonding features of the stoichiometric GaInS3 were calculated using the Density Functional Theory within the Generalized Gradient Approximations (DFT-GGA). Nine Raman-active modes were observed and identified for this compound. The electronic gap was found to be an indirect one and the topological analysis of the electron density revealed that the interlayer bonding is rather weak, thus enabling the intercalation of organic molecules.
