First record of geophagy in Jungle Babbler (Turdoides striata) prior to egg-laying: an instinct for calcium supplement.

Geophagy has been documented in different animal taxa including Aves and particularly in Passeriformes. However, no geophagic activity has been reported in the genus Turdoides of the family Leiothrichidae belonging to the passerine order. Studies reveal the behaviour of geophagy to be aiding in nutrient supplementation, toxin neutralisation, cytoprotection, gut pH stabilisation and parasite liberation. Here, we provide a record of geophagy in Jungle Babbler Turdoides striata in a peri-urban area of Berhampur city in India. Although this species, being insectivorous, was thought to be feeding on insects, nevertheless, close observations confirmed the activity to be a case of geophagy, which was followed up by nest-building, egg-laying and hatching. The soil samples from the geophagic sites (Ca = 2415 mg/kg) contained 130% more Ca than that of the non-geophagic sites (Ca = 1050 mg/kg). The biochemical requirement of calcium throughout the reproductive phase of Turdoides sp. may corroborate the soil consumption instinct, which was also extrapolated from the reproductive success observed, because the demand for calcium in birds remains high during the egg-laying time. Although the possible explanations for geophagy, reported for the first time in this species, were oriented specifically towards Ca supplement, the present findings provide impetus for furthering research in this domain.

Rice with SUB1 QTL possesses greater initial leaf gas film thickness leading to delayed perception of submergence stress.

BACKGROUND AND AIMS: Submergence tolerance in rice is primarily attributed to the action of the SUB1 gene, but other associated traits such as leaf gas film (LGF) thickness, leaf hydrophobicity, porosity and leaf density have been known to aid submergence tolerance in rice. However, association of these traits with SUB1 quantitative trait locus (QTL) has not been demonstrated. In this study, we aim to investigate (1) whether the presence of the SUB1 QTL in the genetic background has any influence on the thickness of the LGF and (ii) whether its removal has any impact on stress perception and submergence tolerance in Sub1 and non-Sub1 rice. METHODS: We examined 12 genotypes (including both Sub1 and non-Sub1 types) for different leaf traits such as initial LGF thickness, leaf hydrophobicity, tissue porosity and leaf density in order to work out the relatioship of these traits to the SUB1 QTL in rice. Furthermore, we investigated the changes in the gene expression profile and different metabolic processes in selected genotypes in the presence and absence of their LGF to study its impact on stress perception and adaptation. KEY RESULTS: The initial thickness of the LGF and hydrophobicity seemed to have a highly positive correlation with the presence of the SUB1 QTL in the genetic background of rice; however, other leaf traits such as porosity and density seemed to be independent of it. Artificial removal of the LGF resulted in partial loss of tolerance, showing increased ethylene production and early induction of anoxia-related genes (SUB1A-1, ACS5, Ramy3D and ADH1) which manifested symptoms such as increased stem elongation, faster chlorophyll and starch breakdown, and partial loss of quiescence in SUB1-containing rice genotypes. Stripping of the LGF resulted in early and enhanced induction of SUB1A-1, indicating a quicker perception of stress. CONCLUSIONS: The presence of SUB1 in the genetic background positively influences surface hydrophobicity and the concomitant LGF thickness of rice. Furthermore, LGF helps in terms of providing better ethylene dissipation and reduced in planta accumulation, owing to the slowing down of ethylene-induced leaf senescence under submergence stress.

Preformed aerenchyma determines the differential tolerance response under partial submergence imposed by fresh and saline water flooding in rice.

Plant's response to fresh- and saline-water flooding and the resulting partial submergence, seems different due to the added complexities of element toxicity of salinity. We identified a few rice genotypes which can tolerate combined stresses of partial submergence and salinity during saline water flooding. To gain mechanistic insights, we compared two rice genotypes: Varshadhan (freshwater-flooding tolerant) and Rashpanjor (both fresh- and saline-water flooding tolerant). We found greater ethylene production and increased "respiratory burst oxidase homolog" (RBOH)-mediated reactive oxygen species (ROS) production led to well-developed constitutive aerenchyma formation in Rashpanjor, which makes it preadapted to withstand fresh- and saline-water flooding. On the contrary, an induced aerenchyma formation-dependent tolerance mechanism of Varshadhan worked well for freshwater flooding but failed to provide tolerance to saline-water flooding. Additional salt stress was found to significantly inhibit the induced aerenchyma formation process due to the dampening of ROS signaling by the action of metallothionein in Varshadhan. Besides, inconspicuous changes in ionic regulation processes in these two genotypes under saline-water flooding suggest preadapted constitutive aerenchyma formation plays a more significant role than elemental toxicity per se in tolerating combined stresses encountered during saline water flooding in rice. Overall, our study indicated that well-developed constitutive aerenchyma provide an adaptive advantage during partial submergence due to saline water flooding in rice as the key process of induced aerenchyma formation is hampered in the presence of salinity stress coupled with partial submergence.

Ionic selectivity and coordinated transport of Na+ and K+ in flag leaves render differential salt tolerance in rice at the reproductive stage.

MAIN CONCLUSION: The present study shows that salt tolerance in the reproductive stage of rice is primarily governed by the selective Na+ and K+ transport from the root to upper plant parts. Ionic discrimination at the flag leaf, governed by differential expression of Na+- and K+-specific transporters/ion pumps, is associated with reduced spikelet sterility and reproductive stage salt tolerance. Reproductive stage salt tolerance is crucial in rice to guarantee yield under saline condition. In the present study, differential ionic selectivity and the coordinated transport (from root to flag leaf) of Na+ and K+ were investigated to assess their impact on reproductive stage salt tolerance. Four rice genotypes having differential salt sensitivity were subjected to reproductive stage salinity stress in pots. The selective Na+ and K+ transport from the root to upper plant parts was observed in tolerant genotypes. We noticed that prolonged salt exposure did not alter flag leaf greenness even up to 6 weeks; however, it had a detrimental effect on panicle development especially in the salt-susceptible genotype Sabita. But more precise chlorophyll fluorescence imaging analysis revealed salinity-induced damages in Sabita. The salt-tolerant genotype Pokkali (AC41585), a potential Na+ excluder, managed to sequester higher Na+ load in the roots with little upward transport as evident from greater expression of HKT1 and HKT2 transporters. In contrast, the moderately salt-tolerant Lunidhan was less selective in Na+ transport, but possessed a higher capacity to Na+ sequestration in leaves. Higher K+ uptake and tissue-specific redistribution mediated by HAK and AKT transporters showed robust control in selective K+ movement from the root to flag leaf and developing panicles. On the contrary, expressions of Na+-specific transporters in developing panicles were either down-regulated or unaffected in tolerant and moderately tolerant genotypes. Yet, in the panicles of the susceptible genotype Sabita, some of the Na+-specific transporter genes (SOS1, HKT1;5, HKT2;4) were upregulated. Apart from the ionic regulation strategy, cellular energy balance mediated by different plasma-membrane and tonoplastic H+-pumps were also associated with the reproductive stage salt tolerance in rice.

Antioxidative efficiency of Triticum aestivum L. exposed to chromium stress.

Wheat (Triticum aestivum L. cv Sonalika) seedlings were grown in presence of K2Cr2O7 (10, 50 and 100 ppm) for 7 days and growth, total chlorophyll, activities of antioxidative enzymes like superoxide dismutase (SOD; EC 1.15.1.1), catalase (CAT; EC 1.11.1.6) and guaiacol peroxidase (POX; EC 1.11.1.7) and lipid peroxidation were determined in root and shoot tissues. Growth of the seedlings was significantly (p < or = 0.05) depressed and at 100 ppm, root length was reduced by 63% and shoot length by 44% in comparison to the respective controls. Total chlorophyll loss in shoots was about 46% at 10 ppm of K2Cr2O7 which further increased to 80% at 100 ppm. Both in root and shoot tissues, activities of SOD and CAT declined with increase of metal in growth medium and it was significant (p < or = 0.05) even at lowest concentration of the metal tested. But POX activity showed a different trend. In root tissues it was decreased whereas in shoots, there was many fold increase in the activity (about 370% over control at 100 ppm). Malondialdehyde (MDA) content increased both in root and shoot tissues, but it reached significant (p < 0.05) level at 50 ppm in roots and at 100 ppm in shoot tissues. Even though antioxidative enzyme activities were not assayed in germinating embryos, inhibition in germination percentage (by 40% at 100 ppm) and increase in lipid peroxidation level (by 71% over control at 100 ppm) were observed in 2-day-old embryos, germinated in presence of K2Cr2O7 (10, 50 and 100 ppm). The results indicated the imposition of oxidative stress situations both during germination and early stages of seedling growth by Cr6 stress, which might be one of the probable reasons behind Cr toxicity in plants.

Parental Presence in Dental Operatory as a Behaviour Management Tool on Children in Bhubaneswar, Odisha, India

Objective: To interpret the change in child's behaviour in presence/absence of parents during dental care. Material and Methods: Sixty children were examined till the age of 12 years visiting the out patient department of pediatric dentistry where parents along with the child were allowed in the operatory. After sometime parents were asked to leave and behavioural changes were noted. During revisit again the behaviour was noted according to Frankl scale. McNemar test was applied to test the behaviour response of children with parental absence/presence. The significance level was set at 5 %. Results: In 1st visit, 78.3% showed positive behaviour and 21.7% showed negative behaviour in parental absence, indicating that the child has more likelihood of showing positive behaviour in the presence of parents (p<0.001). More positive behaviour of the children is noticed, when the parents are present in 3 -5 year age group. In other 6-8 and 9-12 year age group, no difference was noticed in the presence or absence of the parents (p>0.05). In second visit, the negative behaviour reduced. When parents were absent 21.7% showed negative behaviour (p=0.000). This indicated that the child has more likelihood of showing positive behaviour in the presence of parents. Age group-wise analysis revealed that in the 3-5 years age group presence or absence of parents is a significant factor for child's behaviour. This factor is a non-issue in the elder age group like 6-8 years and 9-12 years. When the parents are absent, no significant difference was observed (p>0.05). Conclusion: There was no significant difference in parental presence/absence in elder children while the same can't be said for younger children.