Plant Growth Regulators in Water Stress Tolerance

The present review provides an insight into the relationship between plant growth regulators and water stress with emphasis on metabolic events that regulate growth regulator balance and physiological responses. Possible mechanisms by which ABA controls stomatal function and growth under stress, and interacts with proteins and important osmo-protectants, have been discussed. ABA involvement in signal transduction and root-shoot communication through its effects on gene and gene products is also included. A brief description of involvement of other growth regulators such as cytokinins, ethylene, polyamines and brasssinosteroids in water stress tolerance is also provided. Salient achievements in exploiting the potential of growth regulators in the resistance to water stress in some horticultural crops are also given. Gaps in existing information on plant growth regulator research in water stress tolerance have been summarized

Various cells of the immune system and intestine differ in their capacity to reduce hexavalent chromium

The cells of the immune system form a strong line of defence against foreign substances. The present study was undertaken to investigate the capacity of different cells of Wistar rats to reduce potentially carcinogenic hexavalent chromium (Cr-VI) into less toxic trivalent chromium in vitro. 5× 106 cells were incubated with 10 or 25 μ g ml-1 of Cr (VI) in the form of K2Cr2O7 at 37° C in the presence of 5% CO2 in air. At various time periods the remaining amount of Cr (VI) was measured and the percentage of Cr (VI) reduced was calculated. Among the single cell suspensions from the splenic cells a peak reduction of 55% was observed with the total spleen cells, 40% with the B-lymphocyte-enriched subpopulation, 10% with T-lymphocytes and 24% with the macrophages. The reduction by splenic and peritoneal macrophages was similar. Total thymocytes reduced 54% of the Cr (VI). Since the most common route of entry of chromium is through drinking water and food, intestinal cells were also investigated. Among the intestinal cells the maximum reduction of 100% (of 10 μ g ml-1) was observed with the upper villus cells and 72% with the middle villus cells while reduction was the least (4%) with the crypt cells. The reduction in the intestinal loop in situ was 100%. The time taken by each cell type for the peak reduction to Cr (VI) was markedly different. The findings thus show that the capacity of different cells in the body differs vastly in their capacity and time taken to reduce hexavalent chromium. The most efficient handling of Cr (VI) by the intestine, due to the presence of a variety of cells and bacteria, protects the body from its adverse effects

Gut microflora & toxic metals: chromium as a model

The gastrointestinal tract (GIT) is exposed to various environmental pollutants including metals, that contaminate food and water which may have toxic effects on body. GIT has large amount of microbes that live in symbiosis and help the host in different ways. The resident gut microflora have a significant role to play in detoxification and elimination of the harmful metals from the body. Chromium is a naturally occurring heavy metal found commonly in environment in trivalent (Cr III) and hexavalent (Cr VI) forms. Cr (VI) compounds have been shown to be potent occupational carcinogens. The reduction of Cr (VI) to Cr (III) results in the formation of reactive intermediates that together with oxidative stress and oxidative tissue damage, and a cascade of cellular events including modulation of apoptosis regulatory gene p53 contribute to the cytotoxicity, genotoxicity and carcinogenicity of Cr(VI)-containing compounds. The data discussed here with reference to chromium show that gut microflora have a marked capacity to cope with the increased load of ingested metals and may contribute significantly in the protection against metal toxicity

Effect of Paclobutrazol on Fruit Quality Attributes in Mango (Mangifera indica L.) Cv. Totapuri

Paclobutrazol application restricts vegetative growth while improving flowering and fruiting in mango. In the present study, effect of soil drenching with Paclobutrazol @ 3.0ml m-1 canopy diameter, applied during the 3rd week of August, on fruit quality attributes was investigated in cv. Totapuri. Parameters like fruit weight, total soluble solids (TSS), % acidity, and content of ascorbic acid, carotenoids, lycopene and individual sugars was estimated. Paclobutrazol application increased average fruit weight, TSS and content of ascorbic acid and total carotenoids, and reduced the acidity in fruits compared to fruits in untreated trees. Lycopene content was only marginally influenced by paclobutrazol. In fruits of paclobutrazol treated trees, increase of 23.4% in total sugars, 29.6% in reducing sugars, 77.4% in glucose and 27.8% in sucrose content was recorded over fruits from the untreated trees. Results indicated that, paclobutrazol application improved quality in mango fruit

Effects of chromium on the immune system

Chromium is a naturally occurring heavy metal found commonly in the environment in trivalent, Cr(III), and hexavalent, Cr(VI), forms. Cr(VI) compounds have been declared as a potent occupational carcinogen among workers in chrome plating, stainless steel, and pigment industries. The reduction of Cr(VI) to Cr(III) results in the formation of reactive intermediates that together with oxidative stress oxidative tissue damage and a cascade of cellular events including modulation of apoptosis regulatory gene p53, contribute to the cytotoxicity, genotoxicity and carcinogenicity of Cr(VI)-containing compounds. On the other hand, chromium is an essential nutrient required to promote the action of insulin in body tissues so that the body can use sugars, proteins and fats. Chromium is of significant importance in altering the immune response by immunostimulatory or immunosuppressive processes as shown by its effects on T and B lymphocytes, macrophages, cytokine production and the immune response that may induce hypersensitivity reactions. This review gives an overview of the effects of chromium on the immune system of the body

Effect of Spacing and Pruning on Growth, Yield and Quality of Cv. Deanna Fig (Ficus carica L.)

The effects of tree spacing (5x2m, 5x2.5m, 5x3m, 5x3.5m and 5x4m) and pruning (8 buds/cane, 6 buds/cane and 4 buds/cane) on vegetative growth, physiological parameters, fruit yield and quality were studied in fig (Ficus carica L.) cv. Deanna in the 3rd and 4th year of its growth during the period 2010-12. It was observed that with increase in tree spacing, growth parameters like leaf number, shoot length, internode length, tree-spread, tree height and tree circumference, along with fruit yield both in terms of fruit number and fruit weight per tree, declined gradually under different pruning levels. Increase in pruning level from 8 buds/cane to 4 buds/cane resulted in increased leaf number, shoot length and internode length. Yield characters, viz., fruit number/tree, fruit weight/tree, fruit number/hectare and fruit weight/hectare were marginally influenced by pruning. However, interaction effects of pruning and spacing were found to be non-significant. Consistently declining trends in photosynthesis rate and stomatal conductance, along with increase in leaf water potential value were observed with increase in spacing. Effects of spacing were more conspicuous than those of pruning. Best results for maintenance of vigour and fruit yield were observed under a spacing of 5x2m or 5x2.5m, and 4 buds/cane pruning. Although there was reduction in average fruit size under closer spacing when compared to wide spacing, fruit quality attributes like TSS and acidity were not affected by various treatments. Effects of closer spacing on growth and yield parameters were more pronounced in the 3rd year as compared to the 4th year, showing better response to treatments in young trees. Fruit yield calculated on per hectare basis showed highest fruit number of 116500-133750 and 274500-299500, and fruit weight of 54.5-62.0 and 158.77- 173.30 quintals/ha, respectively, during the 3rdand 4th year of planting under closer spacing of 5x2m and 4 buds/cane pruning

Response of Grape Rootstocks to Soil Moisture Stress

Studies on root and shoot morphology, endogenous hormones and water use efficiency in five grape rootstocks namely Dogridge, 1613 C, Salt Creek, St. George and Vitis champinii clone (VC Clone) at three levels of moisture stress viz., no stress (100% irrigation), 50% stress (50% irrigation) and 100% stress (without irrigation) for 14 days revealed that Dogridge and Salt Creek rootstocks maintained the highest ratios of root to shoot length and root to shoot dry weight as compared to other rootstocks. Water use efficiency increased with increased soil moisture stress and was the highest in Dogridge and Salt Creek. The abscisic acid content in the leaves of Dogridge was maximum at 50% stress followed by that of Salt Creek. Similarly the cytokinin content (both t-ZR and DHZR) was minimum in Dogridge and Salt Creek at 50% stress while it was maximum in 1613 C and St.George. The root to shoot length ratio was positively correlated with ABA content under moisture stress conditions. The higher levels of abscisic acid content in Dogridge and Salt Creek under soil moisture stress suggested their better drought tolerance capacity through a reduction of stomatal conductance and increased water use efficiency

Partial root zone drying irrigation in papaya (Carica papaya L.) for enhanced water use efficiency under limited water situations

Field experiments were conducted during 2015-17 at ICAR-Indian Institute of Horticultural Research, Hessaraghatta, Bengaluru, to standardize the partial root zone drying irrigation in papaya with 12 treatments in RBD design. The results indicated that better soil moisture in the root zone could be maintained under drip irrigation by shifting laterals on either side at fortnightly intervals as compared to fixed laterals with thesame amount of water. Significantly more primary roots (16.5/plant) were observed when irrigation was scheduled on one side with single emitter meeting 60% of the evaporative demand. PRD irrigation through shifting of laterals recorded significantly higher transpiration rate especially at 50% of ER (8.05 m mol m-2 s-1) as compared to the control (3.95m mol m-2 s-1). Further, the same treatment recorded significantly lower fruit cavity index (0.26) with relatively higher fruit volume (1388 cm3). Irrigating papaya only on one side with single emitter resulted in significantly higher T.S.S (13.0%). Higher water productivity (23.7 kg/m3) could be obtained by scheduling the irrigation at 40% evaporation replenishment through shifting of laterals with saving of substantial water (1285m3/ha) resulting in higher water use efficiency (237.4 kg/ha.mm)

Potential impact and controversy of stem cells in public health

Stem cells are versatile in the bodies which are able to both reproduce themselves and to produce more specialized cells. As such, they are of great potential values in repairing and regenerating damaged cells and tissues. Many different kinds of stem cells have been discovered. The most common are embryonic, foetal and adult stem cells. Stem cell research has the potential to provide an increased understanding of development and differentiation, as well as leading to treatments and cures for many diseases. They are important to the future of medicine and public health because with adequate research, stem cells have the potential to treat degenerative conditions through transplanting human stem cells into patients. With sufficient development of stem cell medicine, chronic diseases such as diabetes, heart disease, and Parkinson’s disease will be effectively managed. Embryonic stem cell (ESC) research has been a source of ethical, legal, and social controversy which has slowed the pace of stem cell science and shaped many aspects of its subsequent development

Effect of pretreatment with chromium picolinate on haematological parameters during dengue virus infection in mice

Background & objectives: Dengue virus (DV) has caused severe epidemics of dengue fever (DF) and dengue haemorrhagic fever (DHF) and is endemic all over India. We have earlier reported that exposure of mice to hexavalent chromium [Cr(VI)] compounds increased the severity of dengue virus infection. Trivalent chromium picolinate (CrP) is used worldwide as micronutrient and nutritional supplement. The present study was therefore, carried out to investigate the effects of CrP on various haematological parameters during DV infection of mice. Methods: The Swiss Albino smice were inoculated with dengue virus (1000 LD50, intracerebrally) and fed with chromium picolinate (CrP) in drinking water (100 and 250 mg/l) for 24 wk. Peripheral blood leucocytes and other haematological parameters, and spleens were studied on days 4 and 8 after virus inoculations and the findings were compared with those given only CrP and the normal control age matched mice. Results: CrP in drinking water for 24 wk had no significant effects on peripheral blood cells of mice. On the other hand, there was significant decrease in different haematological parameters following inoculation of normal mice with DV. In CrP fed mice the effects of DV infection were abolished on most of the haematological parameters. Interpretation & conclusions: The findings of present study showed that the adverse effects of DV infection, specially on platelets and leucocytes, were abrogated by pretreatment of mice with CrP. The therapeutic utility of CrP in viral infections including dengue needs to be studied in depth