Potential of Bacillus altitudinis KMS-6 as a biocontrol agent of Meloidogyne javanica

Journal of Pest Science - Root-knot nematodes are among the most dangerous plant pathogens. Biological control is a safer and effective way to manage such pests. In this context, bacterial strain...     

Rainwater Composition at a Regional Representative Site of a Semi-Arid Region of India

Rainwater samples (N = 51) were collected at Rampur, an areafree from anthropogenic activity during the monsoon of 1997 and1998. The concentration of ions follows a general pattern as Ca> NH₄ > Mg > SO₄ > Cl > F >Na > NO₃ > K > HCOO >CH₃ COO. The pH of precipitation ranges between 5.9 and 7.4. The levels of Ca and Mg at this site are higher than otherremote sites, probably dominated by particles of soil origin.Good correlation between Ca, NO₃, SO₄, HCOO and CH₃COO indicate that a fraction of NO₃, SO₄, HCOOand CH₃COO may be derived from soil or associated with Ca and Mg after neutralization. The order of neutralization factorCa (2.19) > NH₄ (1.26) = Mg (1.26) indicates that majorneutralization occurred by Ca. Factor analysis suggested thatCa, Mg, Na, K, NO₃, SO₄, HCOO and CH₃COO arecontributed by soil. NH₃ is known to exist as(NH₄)₂SO₄, NH₄NO₃ and NH₄Cl. Theymay be formed in the atmospheric water droplets by scavenging ofaerosols and reaction of gaseous species.     

Interference of benomyl and methyl-2-benzimidazolecarbamate (MBC) with DNA metabolism and nuclear divisions in Fusarium oxysporum

Methyl-1-(butylcarbamoyl)-2-benzimidazolecarbamate (benomyl) severely decreased DNA synthesis when applied at 3.5 × 10^?6M during the G1 phase of germinating conidia of Fusarium oxysporum; nuclear divisions were completely inhibited at a fungicide concentration of 10 × 10^?6M. The same concentration applied only after the S phase also completely inhibited the nuclear divisions. This dual interference of benomyl with DNA formation and mitosis might be related to a disturbed phosphorus metabolism.     

Differential heat sensitivity of two cool-season legumes,chickpea and lentil,at the reproductive stage,is associated with responses in pollen function,photosynthetic ability and oxidative damage

Increasing temperatures are adversely affecting various food crops, including legumes, and this issue requires attention. The growth of two cool-season food legumes, chickpea and lentil, is inhibited by high temperatures but their relative sensitivity to heat stress and the underlying reasons have not been investigated. Moreover, the high-temperature thresholds for these two legumes have not been well-characterised. In the present study, three chickpea (ICCVO7110, ICC5912 and ICCV92944) and two lentil (LL699 and LL931) genotypes, having nearly similar phenology with respect to flowering, were grown at 30/20°C (day/night; control) until the onset of flowering and subsequently exposed to varying high temperatures (35/25, 38/28, 40/30 and 42/32°C; day/night) in a controlled environment (growth chamber; 12 hr/12 hr; light intensity 750 µmol m⁻² s⁻¹; RH-70%) at 108 days after sowing for both the species. Phenology (podding, maturity) was accelerated in both the species; the days to podding declined more in lentil at 35/25 (2.8 days) and 38/28°C (11.3 days) than in chickpea (1.7 and 7.1 days, respectively). Heat stress decreased flowering–podding and podding–maturity intervals considerably in both the species. At higher temperatures, no podding was observed in lentil, while chickpea showed reduction of 14.9 and 16.1 days at 40/30 and 42/32°C, respectively. Maturity was accelerated on 15.3 and 12.5 days at 38/28°C, 33.6 and 34 days at 40/30°C and 45.6 and 47 days at 42/32°C, in chickpea and lentil, respectively. Consequently, biomass decreased considerably at 38/28°C in both the species to limit the yield-related traits. Lentil was significantly more sensitive to heat stress, with the damage—assessed as reduction in biomass, reproductive function-related traits (pollen viability, germination, pollen tube growth and stigma receptivity), leaf traits such as membrane injury, leaf water status, photochemical efficiency, chlorophyll concentration, carbon fixation and assimilation, and oxidative stress, appearing even at 35/25°C, compared with 38/28°C, in chickpea. The expression of enzymatic antioxidants such as superoxide dismutase, catalase, ascorbate peroxidase, glutathione reductase and non-enzymatic antioxidants declined remarkably with heat stress, more so in lentil than in chickpea. Carbon fixation (assessed as Rubisco activity) and assimilation (assessed as sucrose concentration, sucrose synthase activity) were also reduced more in lentil than in chickpea, at all the stressful temperatures, resulting in more inhibition of plant biomass (shoot + roots), damage to reproductive function and severe reduction in pods and seeds. At 38/28°C, lentil showed 43% reduction in biomass, while it declined by 17.2% in chickpea at the same time, over the control temperature (30/20°C). At this temperature, lentil showed 53% and 46% reduction in pods and seed yield, compared to 13.4% and 22% decrease in chickpea at the same temperature. At 40/30°C, lentil did not produce any pods, while chickpea was able to produce few pods at this temperature. This study identified that lentil is considerably more sensitive to heat stress than chickpea, as a result of more damage to leaves (photosynthetic ability; oxidative injury) and reproductive components (pollen function, etc.) at 35/25°C and above, at controlled conditions.