Small but critical: semi-natural habitat fragments promote bee abundance in cotton agroecosystems across both Brazil and the United States     

Cusser  Sarah  Grando  Carolina  Zucchi  Maria Imaculada  López-Uribe  Margarita M.  Pope  Nathaniel S.  Ballare  Kimberly  Luna-Lucena  Danielle  Almeida  Eduardo A. B.  Neff  John L.  Young  Kenneth  Jha  Shalene 《Landscape Ecology》2019,34(7):1825-1836

Landscape Ecology - Bees are the most important pollinators of crops worldwide. For most bees, patches of semi-natural habitat within or adjacent to crops can provide important nesting and food...  相似文献   

Regeneration and characterization of Swertia chirata Buch.-Ham. ex Wall. plants from immature seed cultures     

Rituparna Kundu Chaudhuri  Amita Pal  Timir Baran Jha 《Scientia Horticulturae》2009

First generation immature seeds (R₁) were collected from a field transferred micropropagated plant and seeds were induced to develop organogenic calli in Swertia chirata, a traditional revenue earning medicinal plant. Half strength MS medium with different growth regulators namely, BA, Kn (2.22–4.44 μM), NAA (2.69–5.37 μM), and 2.26 μM 2,4-D were used to induce callus and organogenesis. Isolated shoots produced roots either in the same medium or in presence of NAA (2.69–10.74 μM) or IBA (2.46–9.8 μM). Fully developed plantlets were successfully transplanted to soil and the fertile seed bearing plants developed. Occasionally plants derived from more than 56 weeks old calli showed some morphological variations. Such variations in regenerated plants is not reflected in their chromosomal constitution, with normal 2n = 26 chromosomes. Likewise, no variation was observed in DNA fingerprinting patterns among the short-term raised culture regenerants, which were morphologically similar to that of the donor plant illustrating their genetical uniformity and clonal fidelity. On the contrary, variation in DNA fingerprinting patterns was observed in long-term culture raised plants.  相似文献   

Management of Sesbania aculeata Incorporation and Nitrogen on the Performance of Transplanted Rice in Calcareous Soil     

Sanjay Kumar Chaudhary  Shankar Jha  Yogeshwar Singh 《Communications in Soil Science and Plant Analysis》2018,49(14):1739-1749

Two field experiments were conducted to optimize the days for decomposition of dhaincha (Sesbania aculeata) with different nitrogen (N) levels and scheduling in transplanted rice in calcareous soil in a split-plot design with three replications. Incorporation of dhaincha one day before transplanting (1-DBT) obviated the need for allowing N gap. Nitrogen scheduling as 50% at active tillering + 40% at panicle initiation + 10% at flowering recorded the maximum grain yield (59.05 q ha^?1) and N–?phosphorus (P)–?potassium (K) uptake. The different N fractions in post-harvest soil were in the order of total N> total hydrolyzable N> non-hydrolyzable N> exchangeable ammonium (NH₄⁺)–?N and nitrate (NO₃^?)–?N. Thus, in calcareous soil, rice may be transplanted immediately after burying the dhaincha without any time gap along with 80 kg N ha^?1. Also, application of nitrogenous fertilizer in three splits, delaying N application until active tillering stage, is beneficial for improving rice productivity.  相似文献   

Sunflower allelopathy for weed control in agriculture systems     

Lakhpat Singh Rawat  R. K. Maikhuri  Yateesh M. Bahuguna  N. K. Jha  P. C. Phondani 《Journal of Crop Science and Biotechnology》2017,20(1):45-60

Recent developments in weed science and allied aspects have involved several interdisciplinary approaches. In this context, indiscriminate use of herbicides for weed control has become a questionable subject, which besides controlling the weeds, the chemical herbicides are harmful in many ways to soil, crops, other plants and the environment as a whole. Taking into consideration ecologically sound weed management, in modern days the reliance on chemical herbicides has decreased and a shift towards naturally occurring biological herbicides has received great attention throughout the world. Sunflower is an annual dicotyledonous plant, herbaceous, erect, and a native of North America. It is thermo and photo-insensitive, hence it can be grown year round in sub-tropical and tropical countries. Only two spp. Helianthus annuus L. and Helianthus tuberosum are cultivated for food, the remaining spp., are ornamentals weeds and wild plants. However, H. annuus is allelopathic and inhibits the growth and development of other plants thus reducing their productivity. Sunflower is a major oil-yielding crop in India and its cultivation in northwest India started 25 to 30 years ago in areas located in the plains. In this region, rice-wheat rotation became very popular owing to its high yields; however, these crops are highly infested by weeds, thus farmers use herbicides for their control. Hence, this rotation consumes a maximum quantity of herbicides in this region, which has resulted in several problems viz., environmental pollution, human health hazards, and development of herbicide resistance in weeds. Thus, serious ecological questions about the reliance on herbicides for weed control in this rotation have been raised. One of the alternatives to overcome these problems is with the use of allelopathic strategies, including the use of weed-smothering crops for weed management and for the sustainability of agriculture. The field, pot culture, and laboratory studies have shown that inclusion of sunflower crops in rotation and intercropping considerably reduced the weed population in the current and succeeding crops. Rhizosphere soil of sunflower drastically smothered the weed germination, population, and biomass. The residual suppression effect of sunflower also persisted in the next crop up to 75 days. Thus, it is conceptualized that the inclusion of such oilseed crops before the rice crop in the rice-wheat rotation may provide satisfactory weed control in the succeeding rice crops and may minimize the use of herbicides. Likewise, the replacement of sorghum by summer sunflower oilseed crops may also help in the control of summer as well as winter weeds. More studies in this direction may provide avenues for satisfactory weed management in agro-ecosystems and may help to minimize the use of herbicides and thereby pave the way to develop sustainable agricultural practices for biodiversity conservation and enhancing biological integrity.  相似文献   

Exogenously applied plant growth regulator protects rice from heat-induced damage by modulating plant defense mechanism     

Lakshmi  G.  Beena  R.  Soni  K. B.  Viji  M. M.  Jha  Uday Chand 《Journal of Crop Science and Biotechnology》2023,26(1):63-75

Journal of Crop Science and Biotechnology - This study was undertaken to investigate the effect of biostimulants such as spermidine (1 mM, 2 mM), indole-3-acetic acid...  相似文献   

Stress mitigating and immunomodulatory effect of dietary pyridoxine in Labeo rohita (Hamilton) fingerlings     

Mohammad Shahbaz Akhtar  Asim Kumar Pal  Narottam Prasad Sahu  Ciji Alexander  Sanjay Kumar Gupta  Arup Kumar Choudhary  Ashish Kumar Jha  Mysore Govindrajan Rajan 《Aquaculture Research》2010,41(7):991-1002

A 60‐day experiment was carried out to delineate stress mitigating and immunomodulatory role of dietary pyridoxine (PN) in Labeo rohita fingerlings exposed to endosulfan. Two hundred and seventy fingerlings were randomly distributed into six treatments in triplicates. Five iso‐caloric and iso‐nitrogenous purified diets were prepared with graded levels of pyridoxine. Six treatment groups were T₀ (10 mg PN+without endosulfan), T₁ (0 mg PN+endosulfan), T₂ (10 mg PN+endosulfan), T₃ (50 mg PN+endosulfan), T₄ (100 mg PN+endosulfan) and T₅ (200 mg PN+endosulfan). The role of pyridoxine on stress mitigation and immunomodulation was assessed by biochemical and haemato‐immunological parameters like aspartate aminotransaminase, alanine aminotransaminase, lactate dehydrogenase, malate dehydrogenase, superoxide dismutase and catalase were significantly (P<0.05) lower while acetylcholinesterase was significantly (P<0.05) higher in pyridoxine‐fed groups. Erythrocytes count, haemoglobin content and total serum protein, albumin, globulin, nitroblue tetrazolium and lysozyme activity were significantly (P<0.05) higher while cortisol and blood glucose were decreased significantly (P<0.05) in pyridoxine‐fed groups. Percentage survival after challenge with Aeromonas hydrophila was highest in T₀ group. The results obtained in present study indicate that dietary pyridoxine supplementation at 100 mg PN kg^?1 diet reduces the endosulfan‐induced stress and triggers immune response in L. rohita fingerlings.  相似文献   

Development of production management strategies for a long-duration rice variety: Rajendra Mahsuri—using crop growth model,DSSAT, for the state of Bihar,India     

Jha  Ranjeet K.  Kalita  Prasanta K.  Jat  Rajkumar 《Paddy and Water Environment》2020,18(3):531-545

Paddy and Water Environment - Increasing crop production is an inevitable demand of a current growing population all over the world. Implementation of best field crop practices potentially enables...  相似文献   

Biology and management of the invasive weed Ageratina adenophora (Asteraceae): current state of knowledge and future research needs     

A S Poudel  P K Jha  B B Shrestha  R Muniappan 《Weed Research》2019,59(2):79-92

Biological invasion is increasing worldwide and the management of invasive species is becoming an important priority for vegetation managers. Success of invasive species management depends on a thorough understanding of the biology of the organism in question and the effectiveness of current management efforts, in order to identify the best practices for management improvement. In this review, we synthesised current biological knowledge of a noxious invasive weed Ageratina adenophora to identify knowledge gaps and assessed management efforts to identify best practices. Finally, we proposed some priority areas for future research to fill knowledge gaps and improve management. Our analysis showed that A. adenophora has already invaded 40 countries, mainly in Asia, Oceania, Africa and Europe. Phenotypic plasticity, allelopathic interference and invasion‐mediated changes in the soil microbial community are the proposed mechanisms that facilitate rapid spread of this weed. However, allelopathy as a mechanism of invasion success of this weed has not been supported by ecologically meaningful experiments. Though mechanical, chemical and biological control measures have been used, their success remains limited and the weed continues to spread in new regions. Among seven biological control agents examined to date, gall fly (Procecidochares utilis) and leaf spot fungus (Passalora ageratinae) have been effective in limited areas to suppress growth of this weed. Some perennial native grasses (e.g. Setaria sphacellata and Lolium perenne) have shown potential to competitively suppress A. adenophora. In conclusion, understanding the invasion mechanisms, exploring further to identify effective biological control agents, combined with approaches of ecological restoration, could help in the management of this weed.  相似文献   

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     

Kalpna Bhandari  Kumari Sita  Akanksha Sehgal  Anjali Bhardwaj  Pooran Gaur  Shiv Kumar  Sarvjeet Singh  Kadambot H. M. Siddique  P. V. Vara Prasad  Uday Jha  Harsh Nayyar 《Journal of Agronomy and Crop Science》2020,206(6):734-758

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.  相似文献   

SNP variation within genes associated with amylose,total starch and crude protein concentration in field pea     

Ambuj Bhushan Jha  Bunyamin Tar’an  Marwan Diapari  Thomas D. Warkentin 《Euphytica》2015,206(2):459-471

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