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气刺微割技术是近十几年来兴起的一种全新采胶技术。从社会经济发展、气刺微割在提高采胶劳动生产率上的优势、气刺微割需增加的费用三个方面,分析气刺微割技术在经济上的可行性。 相似文献
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4年的气刺微割试验结果表明，气刺微割能明显提高产量和割胶劳动生产率，降低干胶含量，而死皮等副作用不明显。采用气刺微割后，必须控制增产幅度，以保持胶树的长期高产稳产。 相似文献
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气刺微割技术是近十几年来兴起的一种全新采胶技术。连续13年在PR107品系上进行的气刺微割试验。结果表明：气刺微割在年割胶刀数比对照少10%的情况下,产量稍比对照的高;死皮等副作用不明显,证明该技术是安全的。 相似文献
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气刺微割技术是应用在巴西橡胶树采胶生产上的一项新技术,核心是乙烯气体高效刺激技术,刺激强度为每周期施用30 mL乙烯,每月3个周期,进行高部位树皮短割线采胶。连续10 a的试验结果表明,气刺微割使得割胶效率大大提高,胶乳干胶含量保持正常水平,树皮产胶解剖结构、功能正常。长流胶是气刺微割获得高产的重要保证。气刺微割是一种安全、高效和可持续的橡胶树采胶技术。 相似文献
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详细介绍了云南植胶区进行气刺微割采胶新技术试验的研究内容及应用实施情况，通过4 a的微割试验示范研究，比较系统的分析了云南微割采胶试验的产量效应、干含、割胶速度、耗皮量、死皮性状、净增长率等生产性数据。说明了微割采胶新技术具有操作简单、割胶速度快、产量好、节约原生树皮、死皮较轻等特点，并能显著降低割胶劳动强度，有效的提高割胶劳动生产率。全面的掌握了这一新技术的应用原理、实施技术、材料配用、操作规程、安全风险，积累了良好气刺微割推广应用基础。 相似文献
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以玉米进行C4光合的全展第5位叶片为材料,分析从叶基部到顶部的解剖结构和叶绿素含量变化,研究玉米C4光合叶片"花环"结构随叶片发育的变化规律。结果表明,玉米第5位叶从基部到顶部都具有完整的典型"花环"结构,维管束鞘细胞(BSC)和叶肉细胞(MC)的体积在叶片发育过程中具有渐变性,从叶基部到顶部BSC和MC均呈先增大后变小的趋势,而且叶绿素a、b和a+b含量呈相同的变化趋势,说明BSC和MC细胞体积与叶绿素含量的变化具有相关性。叶绿素a/b总体呈上升趋势,说明玉米第5叶基部到顶部的光合途径存在C3向C4转变的过程。玉米第5叶不同部位C4光合途径发育的渐变性比前3叶更为明显。 相似文献
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Microcystins (MCs) are the most frequently found cyanobacterial toxins in freshwater systems. Many MC variants have been identified and variants differ in their toxicity. Recent studies showed that the variants MC-LW and MC-LF might be more toxic than MC-LR, the variant that is most abundant and mostly used for risk assessments. As little is known about the presence of these two variants in The Netherlands, we determined their occurrence by analyzing 88 water samples and 10 scum samples for eight MC variants ((dm-7-)MC-RR, MC-YR, (dm-7-)MC-LR, MC-LY, MC-LW and MC-LF) by liquid chromatography with tandem mass spectrometry detection. All analyzed MC variants were detected, and MC-LW and/or MC-LF were present in 32% of the MC containing water samples. When MC-LW and MC-LF were present, they contributed to nearly 10% of the total MC concentrations, but due to their suspected high toxicity, their average contribution to the total MC toxicity was estimated to be at least 45%. Given the frequent occurrence and possible high toxicity of MC-LW and MC-LF, it seems better to base health risk assessments on the toxicity contributions of different MC variants than on MC-LR concentrations alone. 相似文献
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以MC812和郑单958为试验材料,分析其子粒灌浆和脱水特性,研究不同基因型玉米品种子粒灌浆和脱水特性的差异。结果表明,百粒干物重在品种间存在显著差异,MC812平均百粒干物重较郑单958高2.64 g。与郑单958相比,MC812子粒达到最大灌浆速率的时间(Tmax)平均提前4.40 d,灌浆起始势(R0)高0.25,活跃灌浆期(P)长1.33 d。MC812灌浆渐增期的平均灌浆速率显著高于郑单958,灌浆缓增期则与郑单958相当。MC812生理成熟时子粒含水量略低于郑单958,但差异不显著。收获时的子粒含水量在品种间呈极显著差异,MC812收获时的子粒含水量则较郑单958低5个百分点。生理成熟后的脱水速率在品种间呈极显著差异,MC812分别较郑单958高0.15%/d。穗粒数、百粒重和产量在品种间呈极显著差异,MC812产量较郑单958高6.67%、穗粒数和百粒重分别较郑单958高8.56%和8.04%。 相似文献
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Martins A Moreira C Vale M Freitas M Regueiras A Antunes A Vasconcelos V 《Marine drugs》2011,9(10):1715-1730
Blooms of toxic cyanobacteria are becoming increasingly frequent, mainly due to water quality degradation. This work applied qPCR as a tool for early warning of microcystin(MC)-producer cyanobacteria and risk assessment of water supplies. Specific marker genes for cyanobacteria, Microcystis and MC-producing Microcystis, were quantified to determine the genotypic composition of the natural Microcystis population. Correlations between limnological parameters, pH, water temperature, dissolved oxygen and conductivity and MC concentrations as well as Microcystis abundance were assessed. A negative significant correlation was observed between toxic (with mcy genes) to non-toxic (without mcy genes) genotypes ratio and the overall Microcystis density. The highest proportions of toxic Microcystis genotypes were found 4-6 weeks before and 8-10 weeks after the peak of the bloom, with the lowest being observed at its peak. These results suggest positive selection of non-toxic genotypes under favorable environmental growth conditions. Significant positive correlations could be found between quantity of toxic genotypes and MC concentration, suggesting that the method applied can be useful to predict potential MC toxicity risk. No significant correlation was found between the limnological parameters measured and MC concentrations or toxic genotypes proportions indicating that other abiotic and biotic factors should be governing MC production and toxic genotypes dynamics. The qPCR method here applied is useful to rapidly estimate the potential toxicity of environmental samples and so, it may contribute to the more efficient management of water use in eutrophic systems. 相似文献
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Yuan Zhou Fu-Quan Chen Si Chen Qiong Xiao Hui-Fen Weng Qiu-Ming Yang An-Feng Xiao 《Marine drugs》2021,19(9)
In this work, the physicochemical properties of maleic anhydride (MAH)-modified κ-carrageenan (κCar) (MC) were characterized and compared with those of native κ-carrageenan (NC). The Fourier transform infrared spectrum of MC exhibited that κCar was successfully modified. Thermogravimetric analysis indicated that the thermal stability of MC was decreased. When the degree of substitution was 0.032, MC exhibited a low gel strength (759 g/cm2), gelling temperature (33.3 °C), and dehydration rate (60.3%). Given the excellent film-forming ability of κCar, MC films were then prepared and were found to have better mechanical and barrier properties (UV and water) than NC films. With regard to optical properties, MC films could completely absorb UV light in the range of 200–236 nm. The water contact angle of MC films was higher than that of NC films. Moreover, the elongation at break increased from 26.9% to 163%. These physicochemical property changes imply that MC can be employed in polysaccharide-based films. 相似文献
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Kernel water relations play a key role in controlling the duration of grain filling. This duration is controlled by the relationship between kernel water and biomass development, as it determines the timing kernels reach a critical percent moisture content (MC, measured on a fresh weight basis) at which biomass accumulation stops. The time in which this critical percent MC is attained can be affected by the timing kernel net water uptake stops (i.e. maximum water content is reached), or by the relationship between water loss and biomass deposition after maximum water content is attained. Which of the two mechanisms could be behind genotypic differences in maize (Zea mays L.) grain-filling duration was unknown. We also studied the relationship between kernel water and volume development, as it was unknown in this species. Thirteen commercial hybrids were evaluated under different growing environments, and weight, water content and volume of their kernels were measured throughout grain filling. 相似文献
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《Field Crops Research》2006,95(2-3):223-233
Development of maize (Zea mays L.) kernels follows a predictable pattern involving rapid increase in dry weight and large changes in water content (WC). We showed previously that final kernel weight (KW) was closely correlated with maximum WC achieved during rapid grain filling. The objectives of the current work were (i) to test if percent moisture content (MC, measured on a fresh weight basis) could be used to normalize genetic and environmental variations in kernel development shown to affect final KW and (ii) to determine whether final KW could be predicted from kernel WC prior to rapid grain filling. The data examined included results from five hybrids varying more than 2-fold in final KW grown in the field, and from previously published results. When KW and WC were expressed relative to their maximum values obtained during kernel development, a single model described the relationship between dry weight accumulation and MC for the larger seeded hybrids (199–352 mg kernel−1) and published results (222–359 mg kernel−1). Two smaller seeded yellow-flint popcorn hybrids, however, accumulated less dry matter per unit moisture than expected. Nonetheless, all genotypes exhibited a common developmental relationship between kernel WC (expressed as a percent of the maximum value) and MC under well-watered conditions. A new model was developed to couple this developmental relationship to final KW. This model accurately predicted final KW from kernel WC values measured prior to rapid grain filling (∼80% MC; root mean square error, RMSE, of 28.9 mg kernel−1) for all hybrids examined and all published results for which KW and kernel WC data were available. The model also provided a simple means to determine whether final KW was limited by photosynthate supply during kernel development. 相似文献
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耐草甘膦和耐草铵膦是转基因作物育种重要的目标性状。将耐草甘膦基因MC1-EPSPS构建到含有bar基因的植物表达载体pTF101.1中，通过农杆菌介导法转入玉米材料Hi-II中，从而获得兼具耐受草甘膦和草铵膦性状的转基因玉米材料 CM8401。目的基因PCR检测显示，MC1-EPSPS和bar基因稳定整合到玉米基因组中。目的蛋白试纸条检测结果显示，MC1-EPSPS蛋白和PAT蛋白在转基因玉米世代间中表达稳定。田间除草剂耐受性鉴定试验表明，转基因玉米CM8401对草甘膦和草铵膦都具有良好耐受性，可耐受4倍推荐中剂量的草甘膦和草铵膦。 相似文献
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Roque L. Evangelista 《Industrial Crops and Products》2009,29(1):189-196
Whole lesquerella seeds with 6% (as is) and 12% moisture content (MC) were extruded at different residence times by varying screw speeds and feed rates. The temperature of the extrudate was recorded and its MC was determined. The extent of seed cooking was evaluated by measuring the protein solubility and thioglucosidase (TGSase) activity in the extrudate. Uncooked whole seeds (UWS), whole seeds cooked in seed cooker (CWS), and extrusion-cooked seeds (ECS) were screw pressed and the crude oils were analyzed for foots, free fatty acid (FFA), phosphorus, calcium, magnesium, and sulfur. The screw speed and feed rates employed resulted in residence times ranging from 22 to 110 s. The corresponding exit temperatures of the extrudates ranged from 88 to143 °C. Seeds with 6% initial MC dried to 4.3% at extrudate temperatures ≤125 °C regardless of residence time, while seeds with 12% initial MC came out at 7–9% MC, Extruding seeds with 6 and 12% starting MC for 34 and 41 s, respectively, provided the same degree of cooking as that of 12% MC CWS. All CWS and ECS tested negative for TGSase activity. ECS with 6% initial MC generated much higher foots (6.4–9.4%) in the oil compared with that of the 12% MC ECS (1–1.7%). The crude oils from CWS had the lowest FFA content at 1.25%. Crude oils from UWS and ECS had FFA ranging from 1.4–2.8%. The crude oil from 12% MC CWS had 374 ppm sulfur which was 3–8× higher than what were found in crude oils from 6% MC CWS and ECS. The highest P (23 ppm), Ca (14 ppm), and Mg (6 ppm) levels in the crude oil were from 12% MC CWS, which were comparable to total degummed oils. An 81% oil recovery from 6% MC ECS (22 s residence time) was obtained at 19 rpm expeller screw speed. Increasing the expeller's screw speed from 19 to 37 rpm decreased the oil recovery by 0.2%/rpm, increased the throughput by 3.3 kg/rpm from 70 to 130 kg/h, and reduced the press load from 91 to 67%. 相似文献