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71.
M. Das P. H. Zaidi M. Pal & U. K. Sengupta 《Journal of Agronomy and Crop Science》2002,188(4):219-224
An experiment was undertaken using open‐top chambers to study the effect of CO2 enrichment on crop growth and to assess the variation related to the time of CO2 exposure. In general, enriched CO2 conditions (600 ± 50 p.p.m.) in the chamber positively affected the growth and development of mungbean (Vigna radiata), a short‐duration (60–65 days) summer pulse crop. However, there was significant variability in the effect of the crop stage/time of CO2 exposure. It was observed that high CO2 exposure at an early growth stage [0–20 days after germination (DAG)] had a larger effect than that at a later growth stage (21–40 DAG). The experiment also provided a means of assessing the short‐ and long‐term effects of elevated CO2 on the carbon exchange rate at both stages of exposure. The study revealed that the sensitivity of plants to high CO2 was more pronounced with respect to net photosynthetic rate. The overall photosynthetic activity gave greater growth and development of plants under high CO2. 相似文献
72.
Clinogyne dichotoma , Salisb, belonging to the family Marantaceae, is a perennial crop with remarkable morphological characteristic. Present study on the anatomical features revealed their adaptability in waterlogged low-lying marshy lands unsuitable for the cultivation of any other crop. 相似文献
73.
对不同压力和温度下压制的加拿大一枝黄花(Solidago canadensis L.)燃烧块的燃烧特性进行了试验分析。结果表明,不同压力压制的燃烧块其燃烧效率差异显著;不同温度下压制出的燃烧块其燃烧效率差异极显著,燃烧时间和无焰燃烧温度差异显著;不同压力、温度及两者的交互作用与各指标间的差异均不显著。经多重比较,各种压力下,60℃压制出的燃烧块是最优的,可以为用户提供优质的燃烧块。同时,压制燃烧块过程中,加温不应超过70℃,否则燃烧块的燃烧特性会明显变差。 相似文献
74.
Processing chamber is an important part of high-frequency electromagnetic water processor. To determine what kind of processing chamber has better effect of antiscaling, the software, Ansoft Maxwell, which is based on the finite element method, is applied to simulate electromagnetic energy distribution in two common processing chambers. One processing chamber is set with coaxial electrodes and the other one is wrapped by spirals. The electromagnetic energy released to water and the distribution of instantaneous energy density of each chamber are compared. According to the simulation analysis, when the same electrical excitation is imposed on the same volume of water, electromagnetic energy of processing chamber with coaxial electrodes is far more than that of processing chamber wrapped by spirals. However, the electromagnetic energy of processing chamber with coaxial electrode decreases from the anode to the cathode, while the electromagnetic energy of processing chamber wrapped by spirals is distributed evenly. These analysis results can be definitely instructive to design the chamber of high-frequency electromagnetic processor. 相似文献
75.
对BIFMA M7.1-2007《办公家具系统、部件和座椅中散发的挥发性化合物测试方法》标准进行了解读,概述了该标准的适用范围、试验原理和方法,以及该标准在实际应用中的局限性,提出了控制办公系统家具中甲醛和VOC污染物以提高办公场所空气质量的指导意见。 相似文献
76.
Carlson D Fernandez JA Poulsen HD Nielsen B Jacobsen SE 《Journal of animal physiology and animal nutrition》2012,96(2):198-205
Saponin-containing feed additives have shown positive effects on pig performance. Quinoa hull has high saponin content and may be of interest as a feed additive. This study aimed to evaluate quinoa hull meal (QHM) as a feed additive in a pig diet. The effects of QHM were assessed for three dosages of South American (SA) origin (100, 300 and 500 mg/kg) and one dosage of Danish (DK) quinoa (300 mg/kg). In addition, the effect of dietary SA-QHM and SA-QHM-extract on jejunal epithelial physiology was studied ex vivo in Ussing chambers. The experiment included 400 piglets weaned at 28 ± 2 days of age and the experimental period was 4 weeks. Piglets were weighed initially and finally and feed intake registered. The ex vivo studies were performed with epithelium from 40 pigs receiving control or SA-QHM. Epithelium from each pig was placed into eight Ussing chambers, where four concentrations of SA-QHM-extract were added. Epithelial permeability, Na(+)-dependent glucose transport and serotonin (5-HT) and theophylline-induced secretion were measured. The results showed that QHM had no influence on piglet's growth (p = 0.41) or feed intake (p = 0.17). In spite of a large difference in saponin content between SA-QHM and DK-QHM (28.7% and 2.0% w/w respectively) the source did not affect pig performance. The ex vivo studies revealed no effect (p > 0.05) of adding QHM-extract into the medium. The permeability and glucose induced absorption were highest (p = 0.003 and p = 0.04 respectively) in epithelium from pigs that consumed 100 or 300 mg/kg SA-QHM. The secretory response to 5-HT was not affected (p = 0.59) by dietary treatments, but the theophylline-induced secretion decreased (p = 0.02) with increasing dietary SA-QHM. The changes in epithelial physiology measured ex vivo did not affect animal performance in vivo in this study. 相似文献
77.
《Scandinavian Journal of Forest Research》2012,27(1-4):441-453
Cuttings were made from six‐year‐old seedlings of Picea abies L. (Karst.) that had been studied in the Stockholm phytotron. The seedlings belonged to four full‐sib families, one being of French origin, one of North‐Swedish origin and two being hybrids between parents of North‐Swedish and French origin. Nine clones from each family were included. After the rooting phase, the cuttings were exposed to the same cultivation regimes as the seedling ortets. Characteristics of growth rhythm, percentage free growth and leader length were recorded during the 2nd to the 5th growth period (GP). Plagiotropic growth habit was recorded in the 3rd to the 5th growth period, and, characteristics of the rooting phase were studied. A juvenile behaviour very similar to that characterizing growth periods 2–3 of the seedlings was observed for growth rhythm characteristics and for free growth capacity during GP2 of the cuttings. The absolute value of the differences between each observation of the seedling ortets in GP6 and the means of the cuttings in GP2 produced a new variable that quantified the degree of rejuvenation. This new variable was meaningfully calculated only for growth rhythm and growth pattern variables. A gradual reversion of the growth rhythm occurred for the cuttings, which corresponded to the change with increasing age for the seedlings. The capacity for free growth, on the contrary, disappeared already in GP3 for the cuttings, except for the French family. A large variation in the rejuvenation ability between families was observed. Furthermore, the rejuvenation ability was negatively correlated with the ability to grow plagiotropically. 相似文献
78.
《Scandinavian Journal of Forest Research》2012,27(1-4):55-66
In full‐sib families of Picea abies (L.) Karst. (Norway spruce) the dynamics of juvenile growth and the inheritance of the most important growth characters were analysed in six growth periods in climate chambers followed by two additional growing seasons in a nursery. The full‐sib families were of French and North Swedish origin including both within and between provenance crosses. All growth rhythm characters changed over time. For instance, number of days to budbreak increased, whereas days to budset decreased, as growth periods advanced. Concurrent with the changes in growth rhythm, free growth decreased with increasing age. Half of the total variation for different growth rhythm characters within a growth period could in most cases be explained by provenance effects. Early selection is, therefore, meaningful to reduce damage by frost and mortality. Furthermore, the actual distances between family means decreased substantially with increasing age, and the actual length of the shoot elongation period decreased from 31 days during the second growth period to 16 days during the sixth. We suggest therefore that selection together with some treatment in the nursery that alters the growth rhythm of the seedlings are the best ways to increase frost resistance. Tree height was influenced by a set of complex gene actions that changed over time. Provenance effects were important during the first two growth periods. Subsequently, non‐accumulative within provenance family variance took over. If this pattern holds true in general, juvenile selection for height growth in Norway spruce cannot be made as early as that for growth rhythm. 相似文献
79.
通过提取动脉脉搏波特征参数,建立了间接测定大鼠动脉血压的多元回归方程。结果表明:脉搏波周期、K值、脉搏波波图面积等参数与动脉收缩压有较好的相关性,与颈动脉有创血压测定法数值比较,有较小差异(P>0. 05),表明所筛选的脉搏波特征参数能准确地反映动脉的每搏收缩压值,但与舒张压相关性较差。该方法简便、准确、稳定性好,便于长期动态观察。 相似文献
80.