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991.
烯效唑对杂交水稻温室秧苗形态、生理特性及产量的影响 总被引:2,自引:0,他引:2
在杂交水稻温室秧苗1 叶1 心期和寄秧15 d 后各喷施1 次50 ~200 mg·L- 1 烯效唑,可使苗高降低,植株干重、分蘖和总根数、白根数增加,茎基部变宽,叶片变宽变短,根系活力增强,叶片的可溶性糖、蛋白质、叶绿素含量及过氧化物酶(POD) 活性、光合速率提高;后期灌浆速率增大,有效穗增加。其中以喷施100 mg·L- 1 处理效果最好,1996 年小区试验比对照增产18-09 % ,1997 年大区对比试验较之对照增产16-20 % 。 相似文献
992.
The deep scattering layers (DSL) in the central equatorial Pacific form an important prey resource in a relatively oligotrophic habitat. In March of 2006, we used a calibrated 38‐kHz SIMRAD EK60 scientific sonar to assess the spatial distribution of the deep scattering layer relative to broad‐scale oceanographic features and fine‐scale physical and biological measurements. We conducted a single continuous transect from approximately 10°S to 20°N at 170°W while measuring acoustic backscatter, current velocity and direction, temperature, salinity, oxygen, and fluorescence with depth, coincident with marine mammal occurrence. These data were combined with remotely sensed sea surface height, chlorophyll, and sea surface temperature data to examine patterns in DSL distribution. To analyze DSL density with depth, acoustic backscatter was binned into surface (<200 m), mid (200–550 m) and deep (550–1000 m) layers. Backscatter was highly correlated with chlorophyll‐a and low sea surface height anomalies and was greatest near the equator. We found high diel variability in DSL depth and scattering intensity between the mid and surface layers as well as a shallowing of the deep layer moving northward across the equator. Marine mammal sightings consisted primarily of odontocetes with their distribution coincident with higher acoustic densities of their forage base. Shifts in DSL distribution and scattering intensity are an important component towards understanding the behavior and distribution of highly migratory predator species. 相似文献
993.
JENNIFER L. MCILWAIN EUAN S. HARVEY SIMON GROVE GLENN SHIELL HAMED AL OUFI NASR AL JARDANI 《Fisheries Oceanography》2011,20(6):497-516
The coastal shelf of the Gulf of Oman experiences periodic upwelling events during the summer months that are driven by the southwest monsoon. It is unclear what role these events play in the spatial and temporal distribution of the region’s fish assemblage. We carried out trials on two different video techniques to characterize the habitat and fish assemblage along the continental shelf margin near Muscat, Oman. Exploratory surveys with a drift stereo‐video revealed three main habitat types: Sand, Reef and Megabenthos. Three areas were chosen for additional sampling using stereo‐BRUVS (‘baited’ remote underwater‐video systems). On two separate occasions (November 2005 and March 2006) replicate stereo‐BRUVS were deployed in each area stratified by the main habitat types. For each teleost and elasmobranch species encountered on the video, an estimate of total body length and the relative abundance (MaxNi) was made. The stereo‐BRUVS recorded a wide range of demersal and pelagic teleosts including species of conservation interest such as sharks, rays and groupers. The drift stereo‐video recorded significantly fewer species than the stereo‐BRUVS (N = 15 versus N = 43). Species diversity from the stereo‐BRUVS increased by 96% in March 2006 (N = 41) compared to November 2005 (N = 23), a pattern consistent at all three areas. The structure of the overall fish assemblage (using canonical analysis of principal coordinates analysis) was highly variable both in time and space. There was ample evidence of strong habitat associations, particularly with depth and seasonal shifts in abundance and diversity. We argue the upward migration of oxygen‐depleted water into the shallow depths during the late monsoon displaces the demersal fish community along this coast. 相似文献
994.
黄海夏季底边界层动物的种类与丰度 总被引:1,自引:0,他引:1
2002年8月沿青岛至济州岛断面,在黄海的4个站位上进行了底边界层动物昼夜连续采样,对底边界层动物的种类组成及其丰度的变动进行了分析研究。结果显示,黄海夏季底边界层动物的主要类群是浅海底动物和中型浮游动物,种类丰度的昼夜差异不显著。主要种类有尖额谐猛水蚤(Euterpina acutifrons)、挪威小毛猛水蚤(Microsetella norvegica)、戴氏猛水蚤(Danielssenia sp.)、小拟哲水蚤(Paracalanus parvus)和双刺纺缍水蚤(Acartia bifilosa)等。底边界层动物的丰度,在细砂底质环境的站位最低,在具有粉砂一黏土底质环境的站位皆较高。通过聚类分析,可将这两种底质环境上的底边界层动物在26.55%相似性水平上分为两个类型。BIOENV分析表明,水深、底层水温及底质类型是影响海洋底边界层动物种类组成与丰度的重要因子。 相似文献
995.
996.
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998.
为研究与优化不同同期发情方案对肉用母牛繁殖受胎率的影响。本研究在半放牧半舍饲模式下分别应用Ovsynch法、二次PG法、CIDR+PG法、CIDR+PG+GnRH法同期发情方案对夏洛莱牛、新疆褐牛、西门塔尔牛及相关杂交牛进行处理,在AI后通过直肠触诊和超声检查对牛进行妊娠诊断。结合PG剂量与BCS对受胎率统计分析得出,Ovsynch组、二次PG组分别与CIDR+PG组、CIDR+PG+GnRH组受胎率差异显著(P<0.05),在应用CIDR进行同期处理的牛群中,BCS<3组与其他三组受胎率差异显著(P<0.05);BCS≥8组与其他三组受胎率差异显著(P<0.05)。这些结果表明,不同同期发情方案对牛受胎率有显著影响,而BCS对受胎率也有一定影响。本研究为半放牧半舍饲模式下肉用母牛同期发情方案的选择与优化提供了参考。 相似文献
999.
伊莎笼养蛋鸡骨代谢的增龄性改变 总被引:1,自引:0,他引:1
研究了15、35、58和70周龄伊莎(ISA)笼养蛋鸡骨代谢变化规律.试验结果显示:与15周龄比较,70周龄ISA蛋鸡的碱性磷酸酶(AKP)和抗酒石酸酸性磷酸酶(StrACP)水平分别下降61.06%和54.38%(P<0.05);肱骨、胫骨、股骨和龙骨的放射密度分别增加35.23%、34.86%、28.38%和34.86%(P<0.05);而肱骨、胫骨和股骨的平均皮质骨宽度分别下降11.43%、36.96%和28.75%(P<0.05),皮质骨面积百分率分别下降13.97%、38.02%和28.53%(P<0.05).表明:70周龄ISA蛋鸡骨形成减弱,骨吸收增加,已发生显著的骨质疏松症.皮质骨在产蛋周期的持续性重吸收是笼养蛋鸡骨质疏松症的重要成因之一. 相似文献
1000.