Physiological Responses to Drought Stress in Jatropha curcas Seedlings

Aims: The aim of the study was to investigate the physiological mechanisms of Jatropha curcas seedlings exposed to drought and the possible influence of seedling age. Study Design: A pot experiment was carried out using a completely randomized design with two seedling ages (2- and 3-month-old seedlings), two treatments per age (Watered: fully irrigated, and Unwatered: Not irrigated), six replicates (24 pots). Place and Duration of Study: The experiment was performed in a greenhouse facility located at the Experimental Station “Mauro Deidda” (Department of Agriculture of University of Sassari) at Ottava (Sassari, Italy) between June and September 2011. Methodology: To investigate the responses of 2- and 3-month-old J. curcas seedlings exposed to drought stress on 4th, 8th, 12th, 19th, and 26th day from treatment’s beginning, leaf and soil water content, biometric, gas exchange, and chlorophyll a fluorescence measurements were performed; on 26th day from treatment’s beginning, biometric destructive measurements were carried out. Results: Results support the hypothesis that J. curcas is appropriate to be cultivated in areas with limited water availability or prolonged periods of drought and highlight that mechanisms of drought response are highly influenced by seedling age. J. curcas seedlings maintained a good leaf water status by means of an effective stomatal closure, associated with a reduced aboveground growth and an increased root:shoot ratio. Under drought stress, 2-month seedlings showed a higher allocation of resources to roots compared to 3-month seedlings. Drought resulted in more detrimental effects on the photosynthetic response of 3-month seedlings, inducing the reduction of stomata conductance and the loss of photosystem II integrity. 2-month seedlings were instead able to activate mechanisms of drought tolerance through the activation of excess energy dissipation mechanisms. Conclusion: In the early stage of crop establishment, the transplanting of J. curcas 2-month seedlings proved to be more effective in order to avoid water stress related consequences

Vitamin D prevents pancreatic cancer-induced apoptosis signaling of inflammatory cells

Combined approaches based on immunotherapy and drugs supporting immune effector cell function might increase treatment options for pancreatic ductal adenocarcinoma (PDAC), vitamin D being a suitable drug candidate. In this study, we evaluated whether treatment with the vitamin D analogue, calcipotriol, counterbalances PDAC induced and SMAD4-associated intracellular calcium [Ca2+]i alterations, cytokines release, immune effector function, and the intracellular signaling of peripheral blood mononuclear cells (PBMCs). Calcipotriol counteracted the [Ca2+]i depletion of PBMCs induced by SMAD4-expressing PDAC cells, which conditioned media augmented the number of calcium flows while reducing whole [Ca2+]i. While calcipotriol inhibited spontaneous and PDAC-induced tumor necrosis factor alpha (TNF-\u3b1) release by PBMC and reduced intracellular transforming growth factor beta (TGF-\u3b2), it did not counteract the lymphocytes proliferation induced in allogenic co-culture by PDAC-conditioned PBMCs. Calcipotriol mainly antagonized PDAC-induced apoptosis and partially restored PDAC-inhibited NF-\u3baB signaling pathway. In conclusion, alterations induced by PDAC cells in the [Ca2+]i of immune cells can be partially reverted by calcipotriol treatment, which promotes inflammation and antagonizes PBMCs apoptosis. These effects, together with the dampening of intracellular TGF-\u3b2, might result in an overall anti-tumor effect, thus supporting the administration of vitamin D in PDAC patients

Protection of ash (Fraxinus excelsior) trees from ozone injury by ethylenediurea (EDU): Roles of biochemical changes and decreased stomatal conductance in enhancement of growth

Treatments with ethylenediurea (EDU) protect plants from ozone foliar injury, but the processes underlying this protection are poorly understood. Adult ash trees (Fraxinus excelsior), with or without foliar ozone symptoms in previous years, were treated with EDU at 450 ppm by gravitational trunk infusion in MayeSeptember 2005 (32.5 ppm h AOT40). At 30-day intervals, shoot growth, gas exchange, chlorophyll a fluorescence, and water potential were determined. In September, several biochemical parameters were measured. The protective influence of EDU was supported by enhancement in the number of leaflets. EDU did not contribute its nitrogen to leaf tissue as a fertiliser, as determined from lack of difference in foliar N between treatments. Both biochemical (increase in ascorbate-peroxidase and ascorbic acid, and decrease in apoplastic hydrogen peroxide) and biophysical (decrease in stomatal conductance) processes regulated EDU action. As total ascorbic acid increased only in the asymptomatic trees, its role in alleviating O3 effects on leaf growth and visible injury is controversial

Potential and perspectives of <i>Jatropha curcas</i> plantations in marginal land of Ghana

Jatropha curcas L. is a perennial drought-resistant plant well adapted to marginal lands in arid and semiarid and tropical regions (Divakara et al. 2010). J. curcas is a valuable multipurpose crop and has recently gained lot of importance for the biodiesel production by oilseed and secondary products such as soap, fertilisers, bio-pesticides, cosmetics, and medicine. Furthermore, this energy crop offers the ecological advantage to mitigate soil degradation and desertification and to reclaim wasteland (Achten et al. 2008). Community-based Jatropha initiatives for local use, like small J. curcas plantations in marginal lands, agro-forestry systems with J. curcas intercropping, and agro-silvo-pastoral systems can be seen as efficient opportunities to increase rural development in developing countries. The integration of J. curcas into the rural economy at the village level is able to guarantee access to sustainable and affordable energy, increase rural income, create employment opportunities, and alleviate poverty. Although the global interest, Jatropha physiological properties and agronomic management practices are not thoroughly unravelled (Behera et al. 2010). This contribution will highlight some J. curcas scientific research challenges in the framework of an EU-AID international cooperation project implemented in the West Mamprusi District of the Northern Region of Ghana. Through J. curcas plantations, the main project aims are to provide adequate access and security of sustainable renewable energy supply to rural communities of Ghana, improving their livelihood, and to reduce desertification effects in degraded areas. Within this project, several agronomic experimental works are being carried out, in order to improve the knowledge of J. curcas agronomical management practices which could be specifically addressed to the Ghanaian context. Biometric measurement results of J. curcas propagation (direct seed vs pre-cultivated seedlings) and intercropping systems with cereals are shown