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1.
Paddy and Water Environment - Most of the lands of the southern coastal zone of Bangladesh are protected from tidal flooding and storm surges by embankments constructed during the 1960s and 1970s,...  相似文献   
2.
Rice (Oryza sativa) plants acquired excess photosynthates in the form of nonstructural carbohydrates (NSCs) in their stems and grain. Despite keen interest in rice NSC, the dynamics of NSC accumulation, translocation and re-accumulation have not yet been well investigated. AG1 and AG2 QTLs associated with flooding tolerance through catalyzing starch into soluble sugar in germinating seeds. Here we conducted three experiments, greenhouse and field to lay the groundwork for large-scale diversity studies on grain NSC and some agronomic traits under direct-seeded rice (DSR) system, using elite lines incorporating AG1, AG2 and AG1-AG2 QTLs into the popular varieties PSB Rc82 and Ciherang-Sub1 along with the donors Kho Hlan On (AG1) and Ma-Zhan Red (AG2). In germinating seedlings, soluble sugars increased, while starch concentration decreased gradually especially in the tolerant checks and AG1-AG2 introgression lines under flooded soil. Soluble sugar accumulation in stem started to increase from the vegetative stage and peaked at the panicle initiation stage then gradually decreased towards the maturity stage. But Sub1-AG lines had higher sugar and starch concentrations at different growth stages than other genotypes in wet season 2016 and dry season 2017. Plant survival rate was positively correlated with the stem NSC at the early vegetative stage (21 days after sowing), and stem NSC was positively associated with plant height at different growth stages. Among the tested seeding rate, the most suitable seeding rate, 4 g/m2 with shallow burial depth (0.5 cm), resulted in better seedling establishment, relatively higher seedling vigor index and higher leaf area index under flooding in DSR system. Introgression of AG1-AG2 QTLs had no any negative impact on nonstructural carbohydrate, germination rate, and growth and biomass production.  相似文献   
3.
Jia W  Mondal SP  Naqi SA 《Avian diseases》2002,46(2):437-441
In order to verify a commonly held assumption that only Massachusetts (Mass) serotype of infectious bronchitis virus (IBV) was prevalent in the United States between the 1930s (when IBV was first isolated) and the 1950s (when the use of commercial IBV vaccines began), we examined 40 IBV field isolates from the 1940s. Thirty-eight of those isolates were recognized as Mass serotype viruses based on their reactivity to Mass-specific monoclonal antibody (Mab) and neutralization by Mass-specific chicken serum. The remaining two isolates, N-M24 and N-M39, that did not react with Mass-specific Mab, resisted neutralization by Mass-specific chicken serum, and were neutralized only by homologous chicken antibody were identified as non-Mass IBV. When the first 900 nucleotides (nt) from the 5'-end of the spike (S1) glycoprotein gene and their deduced amino acid (aa) sequences were compared, the two non-Mass isolates differed from each other by 24% and 28%, respectively. In a similar comparison, the non-Mass viruses N-M24 and N-M39 differed from M28, a Mass-type isolate from the 1940s, by 21% and 22% (nt) and 28% and 27% (aa), respectively. These data indicate that antigenic and genetic diversity among IBV isolates existed even in the 1940s. Interestingly, when the N-terminal region of the S1 of M28 was compared to that of M41, a prototype Mass virus that has undergone countless number of in vivo and in vitro host passages, the two viruses differed by only 2% (nt) and 4% (aa). This finding suggests that frequent genetic changes are not inherent in all IBV genomes.  相似文献   
4.
We studied leaf litter fall, decomposition and nutrient release patterns of Shorea robusta and Tectona grandis by using a litter bag technique to better understand the release pattern of nutrients to soil from leaf litter. Annual litterfall varied from 13.40 ± 2.56 t ha?1 a?1 for S. robusta to 11.03 ± 3.72 t ha?1 a?1 for T. grandis and the decay constant (k) of decomposed leaf litter was distinctly higher for T. grandis (2.70 ± 0.50 a?1) compared to S. robusta (2.41 ± 0.30 a?1). Biomass loss was positively correlated with the initial litter C, WSC, C/N and ash content in S. robusta and N, P and K concentration for T. grandis. Biomass was negatively correlated with lignin and L/N ratio for S. robusta and L, WSC, L/N and C/N ratio for T. grandis (P < 0.01). Nutrient use efficiency (NUE) and nutrient accumulation index (NAI) of S. robusta was higher than for T. grandis. The retranslocation of bioelements from senescent leaves ranked as P > N > K. Annual N, P and K input to soil through litterfall differed significantly between the two species in the following order: N>K>P. S. robusta was superior in terms of K and P return and T. grandis was superior in terms of N return. The two tree species showed a similar patterns of nutrient release (K > P > N) during decomposition of their leaf litter. Nutrients of N, K and P were the primary limiting nutrients returned to soil through litterfall with important roles in soil fertility and forest productivity.  相似文献   
5.
Genetic Resources and Crop Evolution - Cicer arietinum L. (chickpea) is one of the most significant legume crops domesticated in the Fertile Crescent. This study was aimed to characterize a diverse...  相似文献   
6.
R.C. Mondal 《Geoderma》1973,9(1):35-41
Ground waters with electrical conductivity of 4.9–7.4 mmhos/cm, a pH of 7.7–8.8 and a Mg/Ca ratio of 0.8–41.5 were equilibrated with a Na-illite in the presence and absence of CaCO3. In the presence of CaCO3, exchangeable Ca, exchangeable Ca+Mg and the exchangeable Ca/Mg of the equilibrated clay increased but exchangeable Mg and Na decreased. The pH values of the ground waters were positively correlated with (1) exchangeable Ca, (2) exchangeable Ca+Mg, and (3) exchangeable Ca/Mg ratio, both in the presence and absence of CaCO3.  相似文献   
7.
Clinical exercise testing in the normal Thoroughbred racehorse   总被引:1,自引:0,他引:1  
To evaluate normal cardiorespiratory and metabolic responses of Thoroughbred horses to a standardised treadmill exercise test, we examined 28 horses ranging in age from 1 to 4 years. The group consisted of eight yearlings, eight 2-year-olds and twelve 3 and 4-year-olds. All horses except the yearlings were in training, and either racing or ready to race, at the time of examination. None of the horses had histories of performance problems. On the first day the horses received a full physical examination, resting electrocardiogram, upper respiratory tract endoscopy and either one or two acclimatisation runs on the treadmill. The following day they were given an exercise test on a treadmill inclined at 6 degrees (+10% slope). The test consisted of 3 min at 4 m/sec, 90 sec at 6 m/sec and 60 sec intervals at 8, 10, 11, 12 and 13 m/sec. During the last 15 sec of each step, blood samples were collected for plasma lactate determination, expired respiratory gases were obtained using an open flow mask system for measurement of oxygen uptake, and heart rate was measured using telemetry electrocardiogram. From these measurements, various derived values were calculated, which have been used by others as indices of exercise capacity. These values included: V200 (speed at HR of 200 bpm), VHRmax (speed at which horses reached maximum HR), VO2-200 (oxygen uptake at a HR of 200 bpm), VO2max (maximum oxygen uptake), VLA4 (speed at which horses reached a plasma lactate of 4 mmol/l) and HRLA4 (HR at which horses reached a plasma lactate of 4 mmol/l). The yearlings had significantly lower values than the older age groups for most of the derived values.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
8.
9.
Heat stress adversely affects wheat production in many regions of the world and is particularly detrimental during reproductive development. The objective of this study was to identify novel quantitative trait loci (QTL) associated with improved heat tolerance in wheat (Triticum aestivum L.) and to confirm previous QTL results. To accomplish this, a recombinant inbred line (RIL) population was subjected to a three-day 38°C daytime heat stress treatment during early grain-filling. At maturity, a heat susceptibility index (HSI) was calculated from the reduction of three main spike yield components; kernel number, total kernel weight, and single kernel weight. The HSI, as well as temperature depression (TD) of the main spike and main flag leaf during heat stress were used as phenotypic measures of heat tolerance. QTL analysis identified 14 QTL for HSI, with individual QTL explaining from 4.5 to 19.3% of the phenotypic variance. Seven of these QTL co-localized for both TD and HSI. At all seven loci, the allele for a cooler flag leaf or spike temperature (up to 0.81°C) was associated with greater heat tolerance, indicated by a lower HSI. In a comparison to previous QTL results in a RIL population utilizing the same source of heat tolerance, seven genome regions for heat tolerance were consistently detected across populations. The genetic effect of combining three of these QTL, located on chromosomes 1B, 5A, and 6D, demonstrate the potential benefit of selecting for multiple heat tolerance alleles simultaneously. The genome regions identified in this study serve as potential target regions for fine-mapping and development of molecular markers for more rapid development of heat tolerant germplasm.  相似文献   
10.
Mannose binding approximately 50 kDa homotetrameric lectin, purified from edible Arum maculatum tuber, was analyzed through SDS-PAGE and studied for its agglutination property using rabbit erythrocytes. Cross reactivity of the purified lectin was verified through western blot using Colocasia esculantum(Family, Araceae) tuber lectin antibody. The insecticidal activity of Arum maculatum tuber lectin (ATL) was tested against two economically important sucking pests, Lipaphis erysimi and Aphis craccivora, in an artificial diet. The LC(50) values for L. erysimi and A. craccivora were determined to be 21 microg/mL and 16 microg/mL, respectively. Addition of alpha-d-mannose in ATL-supplemented diet reduced the aphid mortality. Two major receptor proteins of ATL (approximately 40 kDa and approximately 35 kDa) were detected from the brush border membrane vesicle (BBMV) protein of L. erysimi and A. craccivora guts, respectively, using ligand-binding assay. Alpha-d-Mannose was found to be a deterrent to such binding of ATL to the BBMV receptors.  相似文献   
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