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61.
Micro-environmental factors viz., soil moisture and light intensity are important factors that affect natural regeneration
in forests. These factors vary spatially depending on the overhead canopy density of the forest. The present study focused
on studying the effect of variation of soil moisture and light intensity on natural regeneration of sal species (Shorea robusta) under different micro-environments due to overhead canopy of varying forest density. Experimental plots of 40m× 40m size
were laid under different overhead canopy densities in a small sal forested watershed in the foot hills of Himalayas in Nainital District of Uttarakhand State, India. The plots were monitored
on a long term basis for soil moisture at multi depths, light intensity and natural regeneration of sal. The results of the study revealed that the natural regeneration was highest under C1 (up to-0.30) canopy followed by C2
(0.30–0.50), and C3 (0.50–0.70) canopies. The C3 canopy showed the dying back of sal shoots over 4 years of study. The highest R2 value of linear regression between incremental score of plot regeneration and average soil moisture content was obtained
as 0.156 for average soil moisture content during non-monsoon months at 100 cm depth. The R2 value between incremental score of plot regeneration and annual average light intensity was obtained as 0.688 which indicated
that the regeneration is largely dependent on the light intensity conditions during the year. The multiple linear regression
analysis between the incremental score of regeneration and the average light intensity and average soil moisture content revealed
that that about 80% of variation in regeneration is explained by both the factors. 相似文献
62.
REASON FOR PERFORMING STUDY: Computational fluid dynamics (CFD) models provide the means to evaluate airflow in the upper airways without requiring in vivo experiments. HYPOTHESIS: The physiological conditions of a Thoroughbred racehorse's upper airway during exercise could be simulated. Methods: Computed tomography scanned images of a 3-year-old intact male Thoroughbred racehorse cadaver were used to simulate in vivo geometry. Airway pressure traces from a live Thoroughbred horse, during exercise was used to set the boundary condition. Fluid-flow equations were solved for turbulent flow in the airway during inspiratory and expiratory phases. The wall pressure turbulent kinetic energy and velocity distributions were studied at different cross-sections along the airway. This provided insight into the general flow pattern and helped identify regions susceptible to dynamic collapse. RESULTS: The airflow velocity and static tracheal pressure were comparable to data of horses exercising on a high-speed treadmill reported in recent literature. The cross-sectional area of the fully dilated rima glottidis was 7% greater than the trachea. During inspiration, the area of highest turbulence (i.e. kinetic energy) was in the larynx, the rostral aspect of the nasopharynx was subjected to the most negative wall pressure and the highest airflow velocity is more caudal on the ventral aspect of the nasopharynx (i.e. the soft palate). During exhalation, the area of highest turbulence was in the rostral and mid-nasopharynx, the maximum positive pressure was observed at the caudal aspect of the soft palate and the highest airflow velocity at the front of the nasopharynx. CONCLUSIONS AND CLINICAL RELEVANCE: In the equine upper airway collapsible area, the floor of the rostral aspect of the nasopharynx is subjected to the most significant collapsing pressure with high average turbulent kinetic during inhalation, which may lead to palatal instability and explain the high prevalence of dorsal displacement of the soft palate (DDSP) in racehorses. Maximal abduction of the arytenoid cartilage may not be needed for optimal performance, since the trachea cross-sectional area is 7% smaller than the rima glottidis. 相似文献
63.
Arvind Kumar Rai Rakesh Bhardwaj Amish Kumar Sureja 《Communications in Soil Science and Plant Analysis》2017,48(9):1052-1058
Effect of different manures and pine needles application on soil biological properties and phosphorus availability was evaluated in sandy loam soils. Fertilizers nitrogen, phosphorus, and potassium (NPK); Sesbania aculeata green manure (GM); farm yard manure (FYM); and vermicompost (VC) were applied alone or in combination with pine needles. Microbial biomass carbon, dehydrogenase, and alkaline phosphatase activity increased significantly due to manures and NPK. Pine needles reduced the microbial biomass carbon (MBC) and dehydrogenase activity in FYM and VC but increased in NPK and GM. Acid phosphatase activities were found to be significantly increased by pine needles application in NPK, FYM, VC, and GM as compared to without pine needles counterparts. No significant differences were found in soil solution phosphorus in manure treated soil due to pine needle application, but phosphorus uptake was reduced significantly in these treatments. Pine needles application clearly influenced the soil biological properties without any perceptible effect on nutrient release from the manures. 相似文献
64.
Priyanka CHANDRA Amoolya WUNNAVA Pooja VERMA Amaresh CHANDRA Rakesh Kumar SHARMA 《土壤圈》2021,31(3):496-509
Drought stress affects plant growth and causes significant issues in meeting global demand for food crops and fodder. Drought can cause physiological, physicochemical, and morphological changes in plants, which negatively affects plant growth and productivity. To combat this under the increasing global threat of water shortage and rapid population expansion, it is crucial to develop strategies to meet global food demands. Plant growth-promoting rhizobacteria (PGPR) may provide a safe solution to enhancing crop yields through various mechanisms. These soil bacteria can provide drought tolerance to crop plants, allowing them to survive and thrive in water-scarce conditions. Productions of phytohormones, free radical-scavenging enzymes, and stress-combating enzymes that can increase tolerance to drought-induced stress are key features of plant-associated microbial communities. This review summarizes the beneficial properties of microbes that help plants tolerate water scarcity and highlights the bacterial mechanisms that enhance drought tolerance in plants. 相似文献
65.
Anjula Pandey Rakesh Singh J. Radhamani D. C. Bhandari 《Genetic Resources and Crop Evolution》2010,57(6):929-936
Ziziphus nummularia (Burm. f.) Wight et Arn. is a multipurpose wild economic species well adapted to dry and hot climates of north-western plains,
central India and dry regions of peninsular India. This species is reported here for its potential value in drier regions
of India and may be considered for future plant genetic resource programmes. 相似文献
66.
Different plasticizers (P) such as glycerol, 1,2 propanediol, trimethylol propane, thiodiglycol, and formamide (30% by weight w.r.t. soy protein) were used to prepare soy protein films (coded as SP) by compression molding at 140 °C and 20 MPa. The SP films were immersed in 0.5% (w/v) benzilic acid solution for 26 h to get arylated soy protein films (SP-B) with the evolution of CO2, leading to the formation of diphenylhydroxymethane (DPHM) on the surface. Lotus leaf like structure, on the surface of SP-B film, with high hydrophobicity has been created, supported by the existence of nano/micro spheres. The SP-B and SP films were characterized by Fourier transformed infrared spectroscopy, scanning electron microscopy, thermogravimetric analysis, tensile testing, optical transmittance, contact angle, and biodegradation experiments. The mechanical properties, transmittance, and contact angle of SP-B films increased significantly, compared with SP. The SP-B films exhibited high water resistance in the range of 67–82%. These results indicated attractive interactions (often termed as π-interactions) of DPHM aromatic groups took place in the SP-B films resulting in the formation of nanospheres or microspheres. This work provided a good way for increasing the surface hydrophobicity and the mechanical properties of the protein materials through non-covalent interactions. 相似文献
67.
Phytochemical investigation of Annona squamosa twigs, resulted in isolation and identification of twelve known (1-12) compounds among them one 1-(4-β-D-glucopyranosyloxyphenyl)-2-(β-D-glucopyranosyloxy)-ethane (11) is synthetically known but first time isolated from natural sources. Their structures were elucidated using 1D and 2D NMR spectroscopic analysis. The isolated compounds (2-8, 11) were evaluated for H+ K+-ATPase activity. Three of these compounds (+)-O-methylarmepavine (2), N-methylcorydaldine (3), isocorydine (6) showed promising anti-secretory activity. Activity of these compounds, comparable to the standard drug omeprazole is novel to our finding. Moreover, there is no information accessible regarding the pharmacological effect of A. squamosa on the gastrointestinal system. This study is the first of its kind to show the significant anti-ulcer effect of A. squamosa. The present study aimed to evaluate the gastroprotective effect of A. squamosa (AS) and to identify its active constituents. Anti-ulcer activity was evaluated against cold restraint (CRU), pyloric ligation (PL), aspirin (ASP), alcohol (AL) induced gastric ulcer and histamine (HA) induced duodenal ulcer model and further confirmed through in vitro assay of H+ K+-ATPase activity and plasma gastrin level. AS and its chloroform and hexane fraction attenuated ulcer formation in CRU, PL, HA model and displayed anti-secretory activity in vivo through reduced free, total acidity and pepsin in PL, confirmed by in vitro inhibition of H+ K+-ATPase activity with corresponding decrease in plasma gastrin level. Cytoprotection of AS was apparent with protection in AL, ASP models and enhanced mucin level in PL. 相似文献
68.
Rakesh Sharma 《Communications in Soil Science and Plant Analysis》2020,51(8):1065-1077
ABSTRACT Knowledge of spatial variability in soil properties is critical for effective nutrient management plan in crop production. Poor productivity of apple orchards in Indian Himalayan Region (IHR) is due to lack of information on the variability of soil properties important for enhancing productivity in the region. The study was conducted in apple orchards with the hypothesis that spatial variability of soil properties is high due to adoption of varied management and passive soil factors. The major objectives of the study were to assess the spatial variability of soil parameters, viz. soil pH, electrical conductivity, soil organic carbon along with plant available soil nitrogen (N), phosphorus (P), potassium (K), exchangeable calcium (Ca), and exchangeable magnesium (Mg) at a regional scale through geostatistical methods. Coefficient of variation (CV) indicated that the fertility parameters varied from medium to high in heterogeneity (CV > 20%). Available N was found critical/medium in 69.6% of soil samples and might be one of the limiting nutrients for crop growth, P and K were in high, and OC in very high range. Significant correlation was found between OC with N; pH with K, Ca and Mg and EC with OC, P and K. The semivariogram parameters indicated that the spatial distribution of soil fertility parameters were inconsistent and showed strong to weak degree of spatial dependence for all parameters. The study highlighted the importance of delineation of soil fertility management zones in the apple growing region as a guide for precise and site-specific nutrient. 相似文献
69.
Prakash Chand Ghasal Yashbir Singh Shivay Mukesh Choudhary Rakesh Kumar Verma 《Archives of Agronomy and Soil Science》2017,63(11):1597-1612
Field experiments were conducted to evaluate the effects of zinc (Zn) fertilization on yield potentiality and quality of promising wheat varieties during winter seasons of 2013–14 and 2014–15 at the research farm of the Indian Agricultural Research Institute, New Delhi. Among genotypes, HD 2967 genotype proved as best in realizing the highest grain yield (4.89 Mg ha?1), net returns and benefit–cost ratio besides increased protein (13.4%) and wet gluten (29.4%) content in grain. Highest grain Zn concentration and recovery efficiency (RE) recorded in HD 2851 and HD 2687, respectively. HD 2932 registered lowest grain hardiness index (GHI) followed by PBW 343, indicating their better bread-making quality. With respect to Zn fertilization, application of 1.25 kg Zn Zn–ethylene diamine tetra acetic acid (Zn–EDTA) + 0.5% foliar spray at maximum tillering and booting stages resulted in the highest yields, grain Zn concentration and RE followed by 2.5 kg Zn (ZnSO4·7H2O) + 0.5% foliar spray at both stages. These treatments are also superior most with respect to grain quality parameters such as protein, wet gluten and starch content. From profitability viewpoint, 2.5 kg Zn (ZnSO4·7H2O) + 0.5% two foliar sprays were most remunerative with maximum net returns and benefit–cost ratio. 相似文献
70.
Chiter M. PARIHAR Malu R. YADAV Shankar L. JAT Aditya K. SINGH Bhupender KUMAR Vijay POONIYA Sanatan PRADHAN Rakesh K. VERMA Mangi L. JAT Raj K. JAT Muli D. PARIHAR Hari S. NAYAK Yashpal S. SAHARAWAT 《土壤圈》2018,28(6):952-963
Conservation agriculture(CA)-based best-bet crop management practices may increase crop and water productivity, while conserving and sustaining natural resources. We evaluated the performance of rainy season maize during 2014 under an ongoing long-term trial(established in 2008) with three tillage practices, i.e., permanent bed(PB), zero tillage(ZT), and conventional tillage(CT) as main plots, and four intensified maize-based cropping systems, i.e., maize-wheat-mungbean, maize-chickpea-Sesbania(MCS), maizemustard-mungbean, and maize-maize-Sesbania) as subplot treatments. In the seventh rainy season of the experiment, maize growth parameters, yield attributes, yield, and water-and energy-use efficiency were highest at fixed plots under ZT. Maize growth parameters were significantly(P 0.05) superior under ZT and PB compared with CT. Maize yield attributes, including cobs per m~2(7.8), cob length(0.183 m), grain rows per cob(13.8), and grains per row(35.6), were significantly higher under ZT than CT; however, no significant effect of cropping systems was found on maize growth and yield attributes. Zero tillage exhibited the highest maize productivity(4 589 kg ha~(-1)). However, among the cropping systems, MCS exhibited the highest maize productivity(4 582 kg ha~(-1)). In maize, water use was reduced by 80.2–120.9 mm ha-1under ZT and PB compared with CT, which ultimately enhanced the economic water-use efficiency by 42.0% and 36.6%, respectively. The ZT and PB showed a 3.5%–31.8% increase in soil organic carbon(SOC) at different soil depths(0–0.45 m), and a 32.3%–39.9% increase in energy productivity compared with CT. Overall, our results showed that CA-based ZT and PB practices coupled with diversified maize-based cropping systems effectively enhanced maize yield and SOC,as well as water-and energy-use efficiency, in northwestern India. 相似文献