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41.
The combined occurrence of ocular pigment deposition and glaucoma has been described in Cairn Terriers. Recently, this condition was also observed in two other breeds: the Boxer (two cases) and the Labrador Retriever (one case). Six dogs were referred to the Ophthalmology section of the Department of Clinical Sciences of Companion Animals and to a private referral clinic because of glaucoma or blindness in one or both eyes. In five cases ophthalmic examination showed pigment depositions in the sclera around the entire circumference of the perilimbal zone. Eight enucleated eyes (four eyes of two Cairn Terriers, three eyes of two Boxers and one eye of a Labrador Retriever) were examined microscopically. All eyes showed the same findings: an extensive infiltration of large melanin-containing cells with an eccentric nucleus, located in the iris, ciliary body, retina, choroids and sclera. Transmission electron microscopy of two of the examined eyes revealed that the morphology of most of these cells was consistent with melanophages. While reports in the veterinary literature concerning this condition are limited the cells concerned have been described to be melanocytes. Further research is needed to conclusively identify the cell type. As described in the present report, the histologic and transmission electron microscopic findings suggest a different etiology of the ocular pigment deposition and glaucoma compared with the pigment dispersal syndrome in humans. 相似文献
42.
“荧光”蚕品种雌雄荧光色素的定性及相对量分析 总被引:2,自引:1,他引:1
用高效液相色谱分析和纸上色层分析法 ,对家蚕“荧光”品种雌雄幼虫和茧层的荧光色素进行了定性和相对量分析。结果表明 :构成雌雄茧层荧光色素的种类无显著差异 ,雌雄茧荧光色不同的原因是组成茧荧光色的各种荧光色素相对量不同 ;茧层中的一种Rf值为 0 77的黄荧光色素 ,在熟蚕丝腺中没有检出 ,说明营茧过程中有新的荧光物质形成或有较大的变化 ;5龄幼虫不同发育时期 ,雌雄各荧光色素的相对量不同 ,以荧光黄色素为例 ,雄性随日龄的增加其相对量不断增加 ,而雌性则以 5龄 96h为最高 ,其后逐渐下降 ;雌性幼虫肠壁组织中的Rf值为0 19和 0 5 9的两种明黄色荧光色素 ,雄性幼虫和雌性幼虫的其它组织中没有检出 ,说明雌雄幼虫在色素代谢上也存在差异 相似文献
43.
水肥空间耦合对冬小麦光合特性的影响 总被引:10,自引:0,他引:10
在防雨棚管栽试验条件下,以品种“3279”为研究材料,通过7种不同处理来研究水肥空间耦合对冬小麦光合特性的影响,试验结果表明:不同的水肥耦合处理中,冬小麦的光合速率、气孔导度、细胞间隙CO2浓度有所不同,三者之间有很好的平衡关系。其中,深层施肥处理其小麦在生长后期能够维持较高的光合速率,但气孔导度却有所降低,有效地减少了水分散失,表现出很好的节水潜力。同样水分条件下维持同样高的光合速率时,深层施肥的肥上灌水与肥下灌水相比,其受水分影响小,叶绿素含量下降快。深施肥20 cm处灌水处理,在开花后小麦叶片光合作用最强,气孔导度小,细胞间隙CO2浓度高,具有更好的节水潜力。 相似文献
44.
Enhancement of photosynthesis and growth of tomato seedlings by forced ventilation within the canopy 总被引:1,自引:0,他引:1
A forced ventilation system that directs airflow upward or downward within a canopy was developed for plant culture in order to enhance photosynthesis and growth of the plant canopy. Tomato seedling canopies including the seedlings, growing medium, and a plastic tray were used for the experiments. In the upward and downward ventilation systems, air flows upward and downward, respectively, within the plant canopy; this is achieved by blowing and drawing air from holes (Ø 6 mm) made in plastic pipes positioned on the surface of the growing medium. A horizontal airflow system was used as a conventional system to compare the performance of the experimental ventilation systems. Using the upward and downward ventilation systems, the effects of air directions and air velocities on the CO2 exchange rate of the tomato seedling canopy and the growth of the seedlings were compared with those observed using the conventional horizontal airflow system. The forced ventilation within the plant canopy enhanced the CO2 exchange rate of the canopy and the dry masses of the seedlings by 1.4–1.5 and 1.2–1.3 times, respectively, as compared to the conventional horizontal airflow. When the leaf area index (LAI) increased from 1.2 to 2.4, there was only a 5% decrease in the CO2 exchange rate per unit leaf area in the downward ventilation system, whereas there was a 20% decrease in the CO2 exchange rate per leaf area in the horizontal airflow system. The coefficient of variation for the dry mass of the seedlings was higher in the downward system than in the other systems. These results demonstrate that forced ventilation within the canopy is an effective technique to enhance the gas exchange of the plant canopy and the consequent plant growth. 相似文献
45.
通过水培试验,研究了0、1、8、16 mmol·L-1 4个供氮水平下香根草叶片净光合速率(Pn)、叶绿素荧光参数、抗氧化酶类活性和MDA、脯氨酸含量的变化。结果表明,随着氮浓度的增加,香根草叶片Pn、PSⅡ最大光化学效率(Fv/Fm)、PSII电子传递量子产率(ФPSⅡ)、光化学猝灭系数(qP)、非光化学猝灭系数(NPQ)、超氧化物歧化酶(SOD)和过氧化物酶(POD)活性先升高后降低,8 mmol·L-1氮浓度时达最大,16 mmol·L-1氮浓度时最小,而1 mmol·L-1与8 mmol·L-1氮浓度时相比差异不显著;随着氮浓度的增加,过氧化氢酶(CAT)活性、丙二醛(MDA)含量则先下降后升高;游离脯氨酸(Pro)含量上升。这些结果说明香根草叶片在低氮情况下能保持较高的Fv/Fm、ФPSⅡ、qP和抗氧化酶活性。 相似文献
46.
47.
Effects of deficit irrigation strategies on cluster microclimate for improving fruit composition of Moscatel field-grown grapevines 总被引:1,自引:0,他引:1
Tiago Pedreira dos Santos Carlos M. Lopes M. Lucília Rodrigues Claudia R. de Souza Jorge M. Ricardo-da-Silva João P. Maroco João S. Pereira M. Manuela Chaves 《Scientia Horticulturae》2007
The grapevine plays a very important role in the economic, social and cultural sectors of many regions; however vineyards are often grown in regions under stressful conditions and thus they are vulnerable to climate change. The objective of this research was to investigate the effect of partial root-zone drying (PRD) irrigation on vine water relations, vegetative growth, plant microclimate, berry composition and yield components, compared to conventional deficit irrigation (DI, 50% ETc), full irrigation (FI, 100% of ETc) and non-irrigated vines (NI). The study was undertaken in mature ‘Moscatel’ grapevines (Vitis vinifera L.) grown in Pegões, South of Portugal. Compared to the other irrigated treatments, PRD vines showed a better microclimate at the cluster zone with higher incident photosynthetic photon flux density (PPFD). Within the more open canopies of NI and PRD treatments, berry temperatures were higher than those of denser ones (DI and FI). Compared to the conventional irrigation technique the better microclimate observed in PRD vines was a consequence of a reduction in vine growth, where lower values of leaf layer number, leaf area, canopy wideness, water shoots and shoot weight were observed. In PRD vines we observed a tendency to a development of a deeper root system, while DI and FI showed a more homogeneous root distribution throughout the different soil layers. PRD showed an improvement in berry quality with higher values of flavour precursors, and total phenols concentration without any significant yield reduction compared to DI and FI. 相似文献
48.
从女贞果实中提取色素,对其进行分离纯化,测定其光谱;并采用正交设计方法对女贞果实色素的稳定性进行试验.结果表明:女贞果实色素在20℃,pH值2,氧化剂浓度为0.01%的情况下稳定性好;同时表明pH值对其稳定性影响很小;温度达到80℃时该色素受到破坏,氧化剂(H2O2)的浓度很低时(0.01%),色素就会受到破坏. 相似文献
49.
准噶尔盆地沙漠增温效应对棉花光合速率、蒸腾速率的影响 总被引:2,自引:0,他引:2
沙漠增温效应导致了绿洲不同区域热量资源的分异[1],为了进一步了解沙漠增温效应对绿洲不同区域作物的影响,本文通过在准噶尔盆地沙漠区、距沙漠20 km、70 km区域进行试验,从棉花生理生态的角度分析了准噶尔盆地不同区域的农田小气候、棉花净光合速率(Pn)、蒸腾速率(Tr)的差异。结果表明:(1)准噶尔盆地三个区域之间的光合作用有效辐射差异不大;(2)不同区域的大气温度均呈单峰曲线,距沙漠越近的区域温度越高;(3)不同区域的相对湿度都呈现不断下降的趋势;(4)影响区域间Pn、Tr差异的主要因素是气温的差异。 相似文献
50.
研究了从榆树叶中提取天然绿色素的工艺方法以及其榆树叶绿色素的理化性质。结果表明:从榆树叶里提取绿色素时用75%的乙醇(pH值7.80)为提取液效果较好;该色素溶解性和热稳定性良好,在pH值为5~9时较稳定。该色素具有一定的开发利用价值。 相似文献