Salt tolerant screening in eucalypt genotypes (Eucalyptus spp.) using photosynthetic abilities, proline accumulation, and growth characteristics as effective indices

Eucalypts are highly regarded plantation trees due to their fast growing nature, high water consumption, tolerance to abiotic stresses, and ease of conversion to pulp and paper. We screened five genotypes of Eucalyptus camaldulensis (T5, BD4, 1-7-1, H1, and SH4) and three genotypes of the E. camaldulensis × Eucalyptus urophylla hybrid (H4, 58H2, and 27A2) for salt tolerance. Fresh weight and leaf area in hybrid genotypes (H4, 58H2, and 27A2) were greater than those in the E. camaldulensis population after plantlets were subjected to 200 mM NaCl for 14 d. The chlorophyll a content in hybrid genotypes decreased by 19.71–37.11% compared to 51.45–66.00% decline in E. camaldulensis. Similarly, total chlorophyll content was retained at a high level in the hybrid population, leading to stabilization of the net photosynthetic rate. The amount of proline, an osmolyte, was significantly increased in all Eucalyptus genotypes when exposed to 200 mM NaCl. Multivariate analyses of proline accumulation, photosynthetic pigment degradation, diminishing chlorophyll fluorescence, P _n reduction, and growth inhibition in salt-stressed plantlets of Eucalyptus genotypes were performed to classify salt-tolerant- and salt-sensitive groupings. The hybrid eucalypt genotypes H4, 58H2, and 27A2 were identified as salt tolerant while the selection genotypes of E. camaldulensis, T5, BD4, 1-7-1, H1, and SH4, were classified as salt susceptible.     

17O, 14N and 15N n.m.r. studies of the Co2+ complexes of cyclo(Pro17O-Gly15N) and cyclo(Gly17O-Pro) in aqueous solution

The complexation of cyclo(Pro17O-Gly15N) and cyclo(Gly17O-Pro) with Co2+ ions has been studied by 17O, 14N and 15N n.m.r. spectroscopy in aqueous solution. 17O, 14N and 15N transverse relaxation times and chemical shifts were measured as a function of temperature. The 17O n.m.r. studies unequivocally demonstrate that the cobaltous ion binds to the peptide oxygen of both compounds. The hyperfine coupling constant and the peptide residence times were found to be A = -0.165 MHz and -0.145 MHz, tau m = 16, and 92 microseconds for cyclo(Pro17O-Gly15N) and cyclo(Gly17O-Pro), respectively. The 14N and 15N studies of labeled cyclo(Pro17O-Gly15N) do not indicate binding at either the Gly15N or the Pro14N site.     

Exogenous NaCl salt elicitor improves centelloside content and physio-morphological adaptations in indian pennywort (Centella asiatica)

Journal of Plant Biochemistry and Biotechnology - Salt elicitation in therapeutic plants is one of the most popular techniques to enrich targeted secondary metabolites at cellular levels....     

2,3′-Diamino-4,4′-stilbenedicarboxylic acid sensitizer for dye-sensitized solar cells: quantum chemical investigations

The metal-free organic dye sensitizer 2,3′-diamino-4,4′-stilbenedicarboxylic acid has been investigated for the first time for dye-sensitized solar cell applications. Density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations (performed using the hybrid functional B3LYP) were carried out to analyze the geometry, electronic structure, polarizability, and hyperpolarizability of 2,3′-diamino-4,4′-stilbenedicarboxylic acid used as a dye sensitizer. A TiO₂ cluster was used as a model semiconductor when attempting to determine the conversion efficiency of the selected dye sensitizer. Our TD-DFT calculations demonstrated that the twenty lowest-energy excited states of 2,3′-diamino-4,4′-stilbenedicarboxylic acid are due to photoinduced electron-transfer processes. Moreover, interfacial electron transfer between a TiO₂ semiconductor electrode and the dye sensitizer occurs through electron injection from the excited dye to the semiconductor’s conduction band. Results reveal that metal-free 2,3′-diamino-4,4′-stilbenedicarboxylic acid is a simple and efficient sensitizer for dye-sensitized solar cell applications.     

Universal Optimality of Nearest Neighbour Balanced Block Designs using Second Order Correlated Models

Block designs for observations correlated in one dimension are investigated. Santharam and Ponnusamy (1995) investigated the universal optimality of Nearest Neighbour balanced block designs (NNBD) using first order correlated models (AR(1), MA(1) and ARMA(1,1)). In this article we have investigated the universal optimality of NNBD using second order correlated models (ar(2), and MA (2)).     

CULTURE AND BIOCHEMICAL ANALYSIS OF A TEA ALGAL PATHOGEN,CEPHALEUROS PARASITICUS1

To assess the current situation regarding the incidence of red rust disease in tea plants, an extensive survey was conducted in southern Indian tea plantations covering different tea cultivars and agroclimatic zones. The results indicated that the incidence of disease was more severe in tea seedlings than clones in all the agroclimatic zones. On the other hand, a simple, reliable, and reproducible technique was standardized for culturing Cephaleuros parasiticus G. Karst. isolated from infected tea leaves. Ten isolates were obtained, of which two were screened based on growth rate and culture characters for further studies. Ten culture media were tested for the culturing of C. parasiticus in which Trebouxia and Bristol media were the best followed by George, Go algal, and tea leaf extract media. Variations between isolates (Valparai C. parasiticus field number 27 [VCP27], Munnar C. parasiticus field number 11 [MCP11], and University of Texas culture number 2412 [UTEX2412]) of C. parasiticus were studied based on the growth pattern, protein expression profile, and cellular constituents in the filaments. The quantitative estimation of cellular constituents showed that there was no significant difference in these constituents among isolates. The detection of amino acids in the filaments of C. parasiticus isolates showed 16 free forms and 11 bound forms. Amino acids in bound form were higher in all the isolates than in free form of amino acids. The three isolates of C. parasiticus were closely related, with bands lying between the molecular weight of 116 and 35 kDa.