Morphology and physiology of zinc‐stressed mulberry plants     

Rajesh Kumar Tewari  Praveen Kumar  Parma Nand Sharma 《植物养料与土壤学杂志》2008,171(2):286-294

The aim of this study was to induce symptoms of zinc deficiency and Zn excess and to relate the generation of reactive oxygen species (ROS) and the altered cellular redox environment to the effects of Zn stress in mulberry (Morus alba L.) cv. Kanva‐2 plants. The antioxidative responses of Zn‐stressed mulberry plants were studied by determining malondialdehyde content (MDA, a measure of lipid peroxidation) as indicator of oxidative damage and the ratio of dehydroascorbate (DHA) to ascorbic acid (AsA) as an index of the cellular redox state. The Zn‐deficiency effects appeared as faint paling and upward cupping of the young emerging leaves. The paling intensified with time, and affected leaves finally developed necrotic spots. At advanced stage of Zn deficiency, newly emerged leaves were spindle‐shaped, pale, and small in size. Apart from their stunted appearance, the plants supplied excess Zn did not show any specific visible symptom. Leaf water status of mulberry plant was affected in Zn‐stressed plants. Deficient leaves had decreased water potential (Ψ) and specific water content (SWC), contained less tissue Zn, less chloroplastic pigments, and high tissue Fe and Mn concentrations. However, excess supply of Zn was found to increase Ψ and decrease tissue Fe. Both hydrogen peroxide and MDA accumulated in leaves of Zn‐stressed plants. While the concentration of DHA did not vary in Zn‐deficient leaves, it was increased in leaves of plants supplied excess Zn. The ratio of the redox couple (DHA to AsA) was increased both in Zn‐deficient or Zn‐excess plants. The activities of superoxide dismutase (EC 1.15.1.1), catalase (EC 1.11.1.6), peroxidase (EC 1.11.1.7), and ascorbate peroxidase (EC 1.11.1.11) increased in Zn‐stressed plants. The results suggest that deficiency or excess of Zn aggravates oxidative stress through enhanced generation of ROS and a disturbed redox homeostasis in mulberry plants.  相似文献   

A first-approximation simple dynamic growth model for forest teak plantations in Gujarat state of India     

Vindhya Prasad Tewari  Bilas Singh 《Southern Forests》2018,80(1):59-65

Tectona grandis (teak) is one of the most important tropical timber species occurring naturally in India. In India, teak is the single most important commercial timber species. Scientifically sound growth models, based on advanced modelling techniques, are often not available, although they are necessary for the successful management of teak stands in the country. Long-term forest planning requires mathematical models. In this paper, an attempt is made to develop a dynamic growth model based on the limited data, consisting of three annual measurements, collected from 15 teak sample plots in Gujarat state of India. A biologically consistent whole-stand growth model is presented, which uses the state-space approach for modelling rates of change of dominant height, stand density and stand basal area. A simple model containing few free parameters performed well and is particularly well suited to situations where available data are scarce.  相似文献   

Seasonal effect on rooting behaviour of important bamboo species by culm cuttings     

Y. A. Gulabrao  R Kaushal  S.K. Tewari  J.M.S. Tomar  O.P. Chaturvedi 《林业研究》2012,23(3):441-445

We investigated the influence of season on the rooting behaviour of eight important bamboo species viz., Bambusa balcooa, B.bambos, B. nutans, B. tulda, B. vulgaris, Dendrocalamus giganteus, D.hamiltonii and D. strictus. We collected 2 3 node culm cuttings in three growing seasons viz. spring (March), summer (June) and rainy (August)from superior candidate plus clumps (CPCs) centralized in the germ-plasm garden. Cuttings were placed horizontally in sand and were provided with intermittent misting at regular intervals. Bamboo species exhibited differential rhizogenesis behavior in different seasons. The study reveals significant variation in sprouting and rooting behaviour indifferent bamboo species. B. bambos had maximum rooting (78.89%),followed by B. vulgaris (74.44%). In general, the potential of different bamboo species for rooting was found to be in the order: B. bambos > B.vulgaris > B. balcooa > D. hamiltonii > B. tulda > D. strictus > D.giganteus >B. nutans. The maximum rooting was recorded in spring(56.67%), which was closely followed by summer (54.58%). In winter season, minimum rooting (36.67%) was observed. The interaction effect of species × season was also significant on sprouting and rooting parameters. In B. balcooa, B. nutans, B. vulgaris, D. hamiltonii and D.strictus, cuttings collected in summer season showed maximum sprouting and rooting, whereas, B. bambos, B. tulda and D. giganteus had maximum rooting in spring. The maximum number of roots developed per cutting was observed in B. tulda (43.8) during spring season.  相似文献   

An effective antioxidant defense provides protection against zinc deficiency‐induced oxidative stress in Zn‐efficient maize plants     

Rajesh K. Tewari  Praveen Kumar  Parma Nand Sharma 《植物养料与土壤学杂志》2019,182(5):701-707

Maize plants (Zea mays L. cv. Ganga 2 and cv. Jaunpuri satha) were grown in solution culture under glasshouse conditions at deficient (0 µM) and normal (1 µM) levels of Zn supply. Appearance of visible effects characteristic of Zn deficiency, depression in plant growth, and dry matter yield of the plants indicated that Ganga 2 was more susceptible to Zn deficiency than Jaunpuri satha. Higher susceptibility of Ganga 2 to Zn deficiency was also manifested by a greater decrease in plant dry mass and an increased accumulation of TBARS (thiobarbituric acid reactive substance, describing lipid peroxidation). While total SOD activity was decreased in Zn deficient plants of Ganga 2, it was increased marginally in case of Jaunpuri satha. The marginal increase in total SOD activity in the Zn‐deficient Jaunpuri satha plants was a result of a marked increase in non‐CuZn SOD and only a slight decrease in CuZn SOD. Though Zn deficiency increased H₂O₂ concentration and the activities of H₂O₂‐scavenging enzymes in both the cultivars, there was less increase in H₂O₂ concentration and the activities of peroxidase, ascorbate peroxidase and glutathione reductase were more prominently increased in the Zn‐efficient Jaunpuri satha. Plants of the susceptible variety, Ganga 2, accumulated higher concentrations of glutathione disulfide. It is concluded that the significant decreases in the activities of CuZn SOD (CN‐sensitive SOD) and glutathione reductase, and high concentrations of H₂O₂ predisposed Zn‐deficient Ganga 2 plants to more severe oxidative stress than those of Jaunpuri satha and, therefore, contributed to a greater decrease in dry matter production.  相似文献   

Magnesium deficiency induced oxidative stress and antioxidant responses in mulberry plants     

Rajesh Kumar Tewari  Praveen Kumar  Parma Nand Sharma 《Scientia Horticulturae》2006

The aim of the study was to implicate induction of oxidative stress and antioxidative responses with the effects of Mg deficiency in mulberry plants. Mulberry (Morus alba L.) cv. Kanva-2 plants grown in hydroponics were subjected to deficiency of Mg. Mg-deficient plants developed visible symptoms—deep interveinal chlorotic mottling and necrosis in the older and middle leaves. The decreases in the dry matter yield of plants and concentrations of sugars and starch in the leaves of Mg-deficient plants are suggestive of decreased photosynthetic activity. Mg-deficiency decreased concentrations of photosynthetic pigments, and increased concentrations of H₂O₂ and ascorbate and activities of antioxidative enzymes—peroxidase (POD), ascorbate peroxidase (APX) and superoxide dismutase (SOD). The results suggest induction of oxidative stress by enhancing generation of ROS and inducing alterations in redox status, accompanied by activation of antioxidant machinery including induction of some new SOD isoforms in Mg-deficient mulberry plants. Despite significant increase in H₂O₂, lipid peroxidation was decreased in Mg-deficient plants.  相似文献   

Prevalence and molecular characterization of bovine Cryptosporidium isolates in India     

Paul S  Chandra D  Ray DD  Tewari AK  Rao JR  Banerjee PS  Baidya S  Raina OK 《Veterinary parasitology》2008,153(1-2):143-146

A survey based on PCR assay of 18S SSU rRNA gene revealed a 30.2% infection with Cryptosporidium spp., out of 457 faecal samples collected from neonatal bovine calves across three different regions of India. The PCR-RFLP pattern of the gene in all the positive cases established the species as Cryptosporidium parvum. Highest prevalence was recorded in the monsoon months (37.3%) and in the calves showing acute diarrhoea (32.3%). The calves below 15 days of age were mostly affected (45.1%). The infection was more prevalent in the northern parts (35.4%) of the country than in the eastern or southern parts. Results indicated that C. parvum was the only species of Cryptosporidium prevalent in bovine calves in three different geographical regions of India.  相似文献   

印度热带干旱地区沙漠柚木(Tecomella undulata)同龄林极限林分密度与基面积模型     

Vindhya Prasad Tewari 《林业研究》2010,21(1):13-18

对用于评价印度拉贾斯坦邦热带干旱区沙漠柚木极限林分密度的公式进行了研究。对5个不同密度的林分基面积预测模型进行测试和比较,这些模型属非线性生长函数的轨迹不变量代数差形式。这些模型可根据林分变量,如优势高／公顷、立木数／公顷,预测林分基面积,还可用于评估不同造林方案。利用所收集的22块样地的数据建立模型。使用各种可能的树龄数据结构,用定性和定量标准比较了这些替代模型。使用Akaike信息准则差异统计来分析各种模型的预测能力。结果表明：Hui和Gadow提出的模型预测效果最好,推荐在本研究区域内使用该模型来预测沙漠柚木林分基面积。但是,此模型并未使用间伐林分数据,因此,不能准确地预测林木有明显自然死亡的林分基面积。  相似文献   

Long term effect of soil solarization on soil properties and cauliflower vigor     

T. A. Sofi  A. K. Tewari  V. K. Razdan  V. K. Koul 《Phytoparasitica》2014,42(1):1-11

The effect of soil solarization on physical, chemical and biological properties of soil was studied, along with the response of cauliflower seedlings following solarization. Nursery beds were covered with transparent polyethylene sheet and soil temperature and moisture were recorded. Soil samples were collected five times for analysis. Three cauliflower nurseries were raised at 30-day intervals; germination was recorded 10 days after sowing and seedling length 30 days after sowing. The maximum temperature in solarized soil ranged from 40.2–47.2°C, with an increase of 5.2° to 9.9°C over non-solarized soil. There was a conservation of 5.48% moisture in solarized soil as compared with non-solarized. Solarization significantly increased electrical conductivity, organic carbon, nitrogen and potassium over pre-solarized soil. The mean pH, EC, Ca, Mg, N, P, K and C recorded in solarized soil was higher than in non-solarized. Soil solarization reduced the population of fungi from 25.68 x 10⁴ to 4.8 x 10⁴, bacteria from 20.28 x 10⁶ to 5.66 x 10⁶, actinomycetes from 31.60 x 10⁵ to 4.40 x 10⁵, and reduction in population was recorded even after 90 days, when compared with non-solarized soil. Solarization effectively reduced (>97%) population of plant parasitic and free living nematodes. Cauliflower seedlings in solarized soil had a better vigor index than non-solarized soil. Present findings reveal that soil solarization could be exploited for nutrient management and soilborne pests control, with a better vigor index of vegetable nursery.  相似文献   

Genetical assessment of diploid progenitors of <Emphasis Type="Italic">S. scabra</Emphasis> by isozyme,RAPD and STS markers: a possible strategy for improvement of drought tolerant allo-tetraploid <Emphasis Type="Italic">S. scabra</Emphasis> species     

Sanchita Tewari  Amaresh Chandra 《Euphytica》2008,162(1):39-50

Assessment of genetic variations of two progenitors of S. scabra was investigated employing isozyme, RAPD and STS markers. Earlier reports have conclusively indicated S. seabrana and S. viscosa as two diploid progenitors of allo-tetraploid S. scabra. A total of 476 RAPD bands generated from 32 primers, 104 STS fragments from 17 primer pairs and 73 isoforms from 14 enzyme systems indicated significant sharing of these bands to S. scabra with that of S. seabrana in comparison to its other progenitor i.e., S. viscosa. High frequencies of isozyme band sharing between S. seabrana and S. scabra (0.125–0.30) as well as high genetic similarities (59%) of it with S. seabrana as reveled from dendrogram analysis indicated impact of close proximity of the occurrence of S. seabrana in the development of S. scabra. The proportion of bands shared by RAPD (40%) and STS (40%) markers were also observed high between S. seabrana and S. scabra. However, the numbers of unique bands were less in all these species. More correspondence and sharing of bands by S. seabrana towards S. scabra suggested using selected lines of S. seabrana the genetic base of allo-tetraploid, drought tolerant S. scabra lines can be broaden.  相似文献   

Inheritance of partial resistance to race 2 of Albugo candida in canola-quality mustard (Brassica juncea) and its role in resistance breeding     

Bansal  Thiagarajah  Stringam  & Tewari 《Plant pathology》1999,48(6):817-822

The inheritance of partial resistance to race 2 of Albugo candida was studied in a canola-quality line of Brassica juncea . This partially resistant line was crossed with the susceptible B. juncea cultivar Commercial Brown. F₁, F₁(reciprocal), F₂, BC and doubled haploid generations from the cross were inoculated with a zoospore suspension of race 2 to study segregation of partial resistance. The partially resistant phenotype appeared to be controlled by a single dominant gene that has variable expression. This partial resistance can have implications in breeding for disease resistance against white rust, as adult plants did not develop hypertrophic growth or stagheads under greenhouse and field conditions.  相似文献