盐碱地低盐水池塘网箱套养漠斑牙鲆技术研究     

薄学锋  张汉珍  刘金明  苑春亭  王法琴 《渔业现代化》2008,35(3)

根据漠斑牙鲆(Paralichthys lethostigma)适广温、广盐和较强的抗逆性等优良生态习性,采用地下卤水、盐碱地渗水,通过合理淡水配兑使其适合漠斑牙鲆生理生长需求,在我国中纬度地区利用盐碱地低盐水养殖过洋、暖温性漠斑牙鲆。2004-2005年,利用盐碱地低盐水池塘虾池设置网箱套养漠斑牙鲆349.5m2,产鱼3.749t,产虾55.065t,其中2005年虾池设置网箱套养漠斑牙鲆306m2,产鱼3.245t,平均10.6kg/m2,平均全长34.0cm,体重527.4g,养殖成活率为90.5%,产虾49.003t,平均408.4kg/亩,平均规格11.9cm,养殖成活率为71.23%。虾池设置网箱套养漠斑牙鲆,可充分利用水体空间,促使池塘高产高效,提高养殖经济效益。  相似文献   

常压灌水器在低压条件下水力性能试验研究   总被引：3，自引：0，他引：3  

马晓鹏  龚时宏  王建东  田金霞  胡明罡 《灌溉排水学报》2009,(5)

鉴于目前国内低压滴灌系统中的滴灌带(管)基本沿用常压滴灌下使用的滴灌带(管),对常压滴灌系统中使用较多的国内6种单翼迷宫和内镶片式滴灌带在低压下的水力性能进行了试验研究,试验结果表明,在2~8 m和6~14 m水头压力范围拟合的流量与压力关系式不相同,在2~8 m水头压力范围的流态指数明显高于在6~14 m水头压力范围的流态指数。在较低压力下测定灌水器的制造偏差时,相比额定压力下所测定的结果表现出增大的趋势,即由于灌水器制造工艺和材料配方引起的制造偏差,在工作压力较低时表现的更为明显。  相似文献   

水稻苗期根系铵钾离子吸收的交互作用研究     

燕金香李福明  褚光徐春梅陈松章秀福王丹英 《中国水稻科学》2017,31(4):409-416

【目的】为探讨水稻幼苗根系NH_4~+、K~+吸收的交互作用,深化水稻养分吸收理论,【方法】采用溶液培养的方法,对低钾及高钾浓度下水稻在有铵和无铵时的K~+吸收动力学特征进行了研究,对不同钾浓度下水稻根系NH_4~+的吸收速率进行了比较。【结果】1)当K~+0.2 mmol/L时,水稻根系通过高亲和转运系统吸收K~+服从Michaelich-Menten动力学方程;NH_4~+的存在显著降低K~+的最大吸收速率(Vmax),且降幅随着NH_4~+浓度的增加而增大;NH_4~+对水稻根表载体与K~+的亲和力(Km)影响较小,在1.62 mmol/L NH_4~+浓度下,水稻品种齐粒丝苗和沪科3号的Km分别下降了12.33%和16.46%,远低于Vmax 47.30%和39.21%的降幅。2)当K~+0.5 mmol/L时,水稻根系K~+低亲和转运系统发挥作用,K~+吸收速率随浓度的增加而不断增加,呈不饱和特征;但在相同K~+浓度下,水稻根系的K~+吸收速率随NH_4~+浓度的增加而下降。3)水稻根系对NH_4~+的吸收速率随着NH_4~+浓度的增加而增加;在相同NH_4~+浓度下,水稻根系对NH_4~+的吸收速率受K~+浓度的影响很小。【结论】NH_4~+抑制水稻苗期根系K~+的高亲和转运和低亲和转运,NH_4~+对K~+高亲和吸收的影响主要是由于铵竞争细胞膜上的钾载体所致;外界K~+浓度的变化对水稻幼苗的NH_4~+吸收速率影响很小。水稻铵钾的交互作用主要表现在NH_4~+对K~+吸收的抑制作用。  相似文献   

Polymerisation of gluten proteins in developing wheat grain as affected by desiccation     

《Journal of Cereal Science》2017

The breadmaking quality of wheat is affected by the composition of gluten proteins and the polymerisation of subunits that are synthesised and accumulated in developing wheat grain. The biological mechanisms and time course of these events during grain development are documented, but not widely confirmed. Therefore, the aim of this study was to monitor the accumulation of gluten protein subunits and the size distribution of protein aggregates during grain development. The effect of desiccation on the polymerisation of gluten proteins and the functional properties of gluten were also studied. The results showed that the size of glutenin polymers remained consistently low until yellow ripeness (YR), while it increased during grain desiccation after YR. Hence, this polymerisation process was presumed to be initiated by desiccation. A similar polymerisation event was also observed when premature grains were dried artificially. The composition of gluten proteins, the ratios of glutenin to gliadin and high molecular weight-glutenin subunits to low molecular weight-glutenin subunits, in premature grain after artificial desiccation showed close association with the size of glutenin polymers in artificially dried grain. Functional properties of gluten in these samples were also associated with polymer size after artificial desiccation.  相似文献   

Responses of glutamine synthetase activity and gene expression to nitrogen levels in winter wheat cultivars with different grain protein content     

《Journal of Cereal Science》2017

Glutamine synthetase (GS) plays a central role in plant nitrogen (N) metabolism, which improves crops grain protein content. A pot experiment in field condition was carried out to evaluate GS expression and activity, and grain protein content in high (Wanmai16) and low grain protein (Loumai24) wheat cultivars under two N levels (0.05 and 0.15 g N kg⁻¹ soil). High nitrogen (HN) resulted in significant increases in GS1 and GS2 expression at 10 days after anthesis (DAA), and higher GS activity during the entire grain filling stage. HN also significantly increased yield, grain protein content and protein fraction (except for glutenin of Luomai24) in two wheat cultivars, which indicated that it increased grain yield and protein content by improving nitrogen metabolism. Wanmai16 showed higher grain protein content, gliadin and glutenin content, and had higher expression level of GS2 both in flag leaves and grains at early grain filling stage. However, Luomai24 had greater yield and higher expression level of GS1. The difference expression of GS2 and GS1 genes indicates they had various contributions to the accumulation of protein and starch in wheat grains, respectively. The results suggest that GS2 would be serving as a potential breeding target for improving wheat quality.  相似文献   

Kernel vitreousness and protein content: Relationship,interaction and synergistic effects on durum wheat quality     

《Journal of Cereal Science》2017

Four sets of durum samples were used in this study to further understand the interrelationships among hard vitreous kernels (HVK), protein content, and pigment concentration, with a focus on the interaction and synergistic effects of protein content and vitreousness on durum quality. HVK level increases with higher protein content in the range of 9.5–12.5%, but this relationship is less evident in durum samples with high protein content (12.5–14.5%). Both protein content and kernel vitreousness can significantly affect durum milling quality. White starchy kernels (WSK) in low protein durum have a very detrimental impact on milling and pasta processing quality, but high protein content can mitigate the adverse impact of WSK on durum quality. Although protein content plays a dominant role, higher HVK might contribute positively to pasta firmness. There was no significant difference in yellow pigment content between HVK and WSK. However, pigment loss from semolina to dough was higher for WSK than HVK. Despite the difference in protein content, HVK and WSK have little difference in gluten strength. The monomeric protein was preferentially accumulated in HVK. The glutenin proteins of HVK and WSK were similar in the ratios of 1Bx/1By and HMW/LMW-GS.  相似文献   

斜流泵小流量工况压力脉动数值模拟与实验     

张德胜  刘俊龙  耿琳琳  石磊  张俊杰 《农业机械学报》2017,48(2):117-125

基于标准的Smagorinsky亚格子尺度模型,对斜流泵全流场进行大涡模拟并结合压力脉动实验对小流量工况下的压力脉动和内部流场进行研究。实验结果表明,叶轮进口处的脉动幅值最高,随着流量的降低压力脉动幅值逐渐增加,不同工况下叶轮进口、叶轮出口、导叶进口的压力脉动主频为叶频,但导叶出口脉动主频随着流量的变化而变化。大涡模拟表明,0.8Qopt工况下叶轮进口流动状态较好,叶轮进口轴面速度变化较小,而在0.4Qopt工况下叶轮进口流动状态较复杂,轴面速度变化较大,0.4Qopt工况时叶轮进口冲角增加以及受到相邻叶片叶顶泄漏流的影响,在t*=0.041 6时叶片进口吸力面已发生流动分离,当叶轮从t*=0.041 6旋转到t*=0.124 9时,叶片吸力面流动分离加剧,轮缘处的轴面速度明显升高,同时分离涡的旋转强度也逐渐增强,导致该区域的静压下降,逆压梯度上升,促使回流的产生,当回流到达叶片进口时进口处的静压逐渐恢复,因此叶轮进口流动分离是引起叶轮进口压力脉动幅值增加的重要因素。  相似文献   

基于GIS的低温冷冻灾害风险性评估     

史春彦  张前东  张艳菲  刘鹏  张鲁 《中国农学通报》2017,33(19):116-121

为了提高低温冷冻灾害的防御能力,为政府部门制定防灾减灾规划提供科学依据。本研究基于自然灾害形成机理及风险评估原理,以济南市长清区为例,利用气候资料、历史灾情数据、地理信息数据及社会经济等资料,采用层次分析法和加权综合评价法,借助GIS空间分析技术,通过对致灾因子危险性、敏感性、易损性和防灾减灾能力4个评价指标的空间评价,实现了对长清区低温冷冻灾害的风险性评估和综合区划。结果表明：长清区低温冷冻灾害总体表现为空间化强,没有规则的分布规律,综合风险性总体水平较高。文昌街道办事处、五峰山街道办事处、双泉乡的部分地区综合风险性最高,属于低温冷冻灾害的重点防御区域;轻、低风险主要分布在平安街道办事处、万德镇、马山镇、崮云湖街道办事处的部分辖区。该评估结果将对本地区农作物的种植规划及灾害防御措施的制定提供参考依据。  相似文献   

5种杀虫剂超低容量液剂对玉米田草地贪夜蛾的防治效果   总被引：1，自引：0，他引：1  

刘妤玲  张永生  张生  王芹芹  芮昌辉 《植物保护》2019,45(5):102-105

草地贪夜蛾是新入侵我国的迁飞性重大害虫,为害玉米的心叶、生长点及雄穗等,能引起严重的损伤、烂心、授粉不良等,导致玉米减产甚至绝产。本文评价了5种杀虫剂超低容量液剂通过低容量喷雾对玉米田草地贪夜蛾的防治效果。结果表明,在相同的原药成本下,6%甲维·茚虫威超低容量液剂和1%甲氨基阿维菌素苯甲酸盐超低容量液剂具有优异的保叶效果和杀虫效果,5%氯虫苯甲酰胺超低容量液剂在较低的用量下(有效用量1 g/667m~2)具有良好的保叶和杀虫效果,3%呋虫胺超低容量液剂对草地贪夜蛾幼虫基本无效,但有一定的保叶效果。  相似文献   

花期低温对水稻叶鞘生理及结实率的影响   总被引：1，自引：0，他引：1  

项洪涛  梁晓艳  郑殿峰  李琬  王彤彤  王畅  王立志  李冰  齐德强 《干旱地区农业研究》2019,37(2):114-122

盆栽条件下,以耐冷性不同的2个水稻（Oryza sativa L.）品种龙稻5（耐冷型）和龙粳11（冷敏型）为材料,于开花期在人工气候室进行低温（15℃,分别持续1,2,3,4,5 d）处理,研究开花期低温对不同耐冷性水稻结实率及叶鞘膜透性、抗氧化酶等生理指标的影响。结果表明：低温处理2 d时,龙稻5和龙粳11的花粉活力分别下降了8.21%和16.10%,差异达极显著水平;低温处理3 d后,龙稻5的结实率下降到99.90%,与CK相比差异达到显著水平;低温处理1 d后,龙粳11的结实率下降到60.04%,与对照相比差异达到极显著水平。低温处理提高了水稻叶鞘相对电导率和脯氨酸、可溶性蛋白含量,处理5 d时各指标达最大值,与CK相比,龙稻15和龙粳11分别提高了38.01%和20.77%、25.06%和84.85%、25.82%和23.63%。同时低温处理也提高了叶鞘超氧化物歧化酶（SOD）、过氧化物酶（POD）和过氧化氢酶（CAT）活性,处理3 d时酶活性达最大值,龙稻15和龙粳11分别较CK提高了10.57%和14.90%、86.26%和68.71%、17.73%和28.25%。综上所述,开花期低温引起水稻叶鞘膜脂过氧化程度升高,但也诱导水稻叶鞘抗氧化系统开启、保护酶活性上升以抵御低温伤害;开花期低温导致水稻花粉活力降低并引起结实率降低,耐冷品种较冷敏品种抵御能力强。  相似文献