Savaliram Goga Ghane

Differential growth, physiological and biochemical responses of niger (Guizotia abyssinica Cass.) cultivars to water-deficit (drought) stress

The present study demonstrates the effect of polyethylene glycol-8000 (PEG) and percent field capacity (FC%)-induced water-deficit stress on growth, water status, productivity and various biochemical parameters in Guizotia abyssinica Cass. cultivars (IGP 76, GA 10, No. 71 and IGPN 2004) at seedling and maturity stages of the plant. Cultivar GA 10 showed higher, IGP 76 and No. 71 moderate, and IGPN 2004 least reduction in percent seed germination given PEG stress treatments (0, 10 and 20%). A similar pattern was observed for decreased growth and water content of the seedlings and plants of the cultivars exposed to both kinds of water-deficit stresses. The productivity (number of capitula per plant, number of seeds per capitula and 1,000-seed weight) and total chlorophyll content of cultivar IGPN 2004 was significantly higher in comparison to other cultivars given different FC% treatments (100, 80 and 60%). Significantly higher accumulation of proline, glycine betaine and total soluble sugars and lower damage to membrane lipids under increased water-deficit stress (i.e., at 80 and 60% FC) conditions in cultivar IGPN 2004 suggested its more tolerance capacity to water-deficit stress in comparison to other cultivars. Besides, antioxidant enzyme activities (superoxide dismutase, catalase, ascorbate peroxidase and guaiacol peroxidase) partially demonstrated variations in the tolerance of the cultivars to water-deficit stress. The results suggest that cultivar IGPN 2004 could be considered as more tolerant, and IGP 76 and No. 71 as moderately tolerant, whereas GA 10 was more sensitive to water-deficit stress.

Growth and physiological alterations in Niger cultivars under drought stress

Aim of the present study was to determine differential responses in growth and physiology of tolerant (cv. IGPN 2004) and sensitive (cv. GA 10) cultivars of Niger (Guizotia abyssinica Cass.) using in vitro grown calli under water deficit conditions. The calli were subjected to drought stress using PEG-8000 (–0.16,–0.45,–0.87,–1.42 bar) for 15 d and relative growth rate (RGR), percent tissue water content (% TWC), osmolytes (proline–Pro, glycine betaine—GB, total soluble sugars—TSS) accumulation, malondialehyde (MDA) content as well as antioxidant enzyme activities such as superoxide dismutase (SOD), ascorbate peroxidase (APX) and catalase (CAT) were analysed. Our findings showed that RGR and percent TWC was decreased significantly with the intensity of drought stress in both cultivars, but the RGR reduction was least (five folds) in cv. IGPN 2004 than in cv. GA 10 (6.2 folds). In osmolyte accumulation such as Pro and GB, cv. IGPN 2004 was found superior (5.5 and ten folds higher, respectively) to tolerate drought stress than GA 10; however, no change was observed in TSS accumulation. Further, it was noted that cv. IGPN 2004 caused least oxidative damage to the membranes. It also exhibited better SOD, CAT and APX activities and had higher α-tocopherol content. The least reduction in growth and MDA content and higher osmolytes and antioxidant activities in cv. IGPN 2004 revealed more drought stress tolerance at cellular level. It was suggested that increased drought tolerance of cv. IGPN 2004 was coupled with its better maintenance of RGR, percent TWC, reduced lipid peroxidation, more accumulation of osmolytes and higher antioxidant enzymes.

Growth, physiological, and biochemical responses in relation to salinity tolerance for In Vitro selection in oil seed crop Guizotia abyssinica Cass.

The calli cultures of Guizotia abyssinica (niger) cultivars IGP 76 and GA 10 were exposed to different levels of salt treatments (0, 30, 60, and 90 mM NaCl), in order to evaluate growth, physiological, and biochemical responses. A significant decrease in relative growth rate and tissue water content of GA 10 calli than IGP 76 under salt-stress conditions was associated with higher sodium ion accumulation. Osmotic adjustment revealed by the osmolytes (proline, glycine betaine, and total soluble sugars) accumulation was significantly higher in IGP 76 salt-stressed calli as compared to GA 10. The sustained growth and better survival of IGP 76 calli was correlated with lower malondialdehyde content and increased superoxide dismutase, ascorbate peroxidase, and catalase activities and higher α-tocopherol content in comparison to GA 10. The higher osmolytes accumulation and presence of better antioxidant system suggested superior adaptation of IGP 76 calli on salt-containing medium for prolonged periods in comparison to GA 10. The regeneration frequency, organogenesis, and acclimatization response of the plants derived from salt-adapted calli was comparatively lower than the plants derived from control calli of IGP 76. The growth, physiological, and biochemical characterization of the salt-tolerant regenerated plants exposed to stepwise long-term 90 mM NaCl treatment revealed no significant changes in comparison to the control. Thus, our results suggests the development of an efficient protocol for in vitro selection and production of salt-tolerant plants in self-incompatible crop, niger, and an alternative to traditional breeding programs to increase the abiotic stress tolerance.

Cytopalynological studies in some Convolvulaceae members from northern Western Ghats, India

ABSTRACT This paper presents a cyto-palynological study of four species of Convolvulaceae from the northern Western Ghats of India. Ipomoea clarkei and Operculina tansaensis are endemic to the region, whereas I. diversifolia and O. turpethum show wide distribution. A new cytotype with 2n = 28 was reported for I. diversifolia. The chromosome number 2n = 30 in O. turpethum was in conformity with earlier reports. Chromosome numbers for I. clarkei and O. tansaensis (both with 2n = 30) were reported for the first time. Meiosis was found to be normal. At diakinesis 14 bivalents were observed for I. diversifolia while I. clarkei and O. tansaensis showed 15 bivalents. In all the species, chromosomes were small with median region centromeres. The largest chromosome was recorded in I. clarkei (2.15 ± 0.25 µm) and the shortest for I. diversifolia (1.62 ± 0.19 µm). The karyotypes were symmetrical and exhibited Stebbins’s 4a category. Pollens were pantoporate-echinate in both the Ipomoea species and tricolpate-smooth in Operculina. Abbreviations: THL, total haploid chromosome length; CVCL, coefficient of variation of chromosome length; MCA, mean centromeric asymmetry; L, length of the largest chromosome; MCL, mean chromosome length; r, mean arm ratio; R, ratio between the largest and the smallest chromosome of the complement; St, type of asymmetry.

Proximate composition, antioxidant activities and phenolic composition of Cucumis sativus forma hardwickii (Royle) W. J. de Wilde & Duyfjes

In the present investigation, nutritional, anti-nutritional and antioxidant potential of Cucumis sativus forma hardwickii was evaluated for the first time. The results revealed that leaf and fruit of Cucumis sativus f. hardwickii were rich source of ash, carbohydrate, fat, fibre and proteins. In addition, appreciable amounts of Vitamin C and E were also observed. Considerable antinutritional factors in leaf and fruit were noted which can be reduced by different processing methods. In sequential solvent extraction, methanol found to be the best in the extraction of antioxidants, which was supported with the highest antioxidant activities. Among all ¬¬the extracts, it was noted that leaves extracted with methanol had higher amount of phenols and flavonoids than fruit. In addition, the potent radical scavengers mainly phenolics were detected using RP-HPLC where tannic acid, gallic acid and hydroxybenzoic acid were also quantified in leaf and fruit. Superior antioxidant potential may be due to the presence of other bioactive compounds present in fruit. Additional research on bioactive properties of this plant is needed to explore this neglected wild cucumber for nutraceutical purpose and as a functional food.