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1.
目的:评价口温蜡在软腭缺损修复中制取缺损腔功能印模的应用效果。方法:对11例硬软腭缺损患者分别采用口温蜡和藻酸盐制取缺损腔印模,制作阻塞器,使用两种阻塞器各1个月后,比较其戴口温蜡取模制作的阻塞器时(甲组)、戴藻酸盐取模制作的阻塞器时(乙组)和不戴阻塞器时(丙组)三种情况下,患者口鼻漏情况的主观满意度、语音清晰度(Speech Inteligibility,SI)以及单韵母频谱分析值,分别对其进行比较。结果:甲组的口鼻漏满意度、语音清晰度及单韵母[i]音F1、F2、[u]音F2、[ü]音F2的频率值均显著高于其余两组(P0.05)。结论:口温蜡取模制作的阻塞器能够明显改善患者因腭咽闭合功能不全造成的口鼻漏、言语障碍等状况。  相似文献   
2.
倪郁  宋超  王小清 《生态学报》2014,34(15):4160-4166
以野生型拟南芥与蜡质突变体cer1、cer4为试验材料,通过研究核盘菌胁迫对拟南芥茎表皮蜡质结构及组分含量的影响,揭示核盘菌侵染与表皮蜡质的关系。扫描电镜结果显示,野生型拟南芥蜡质晶体以垂直于表面的杆状、块状结构为主;突变体cer1晶体类型以水平的松针状、块状结构为主;突变体cer4蜡质晶体以垂直片层结构为主。核盘菌胁迫下,拟南芥蜡质晶体结构及分布形态发生变化。蜡质层结构在核盘菌胁迫下表现为:杆状、松针状蜡质晶体减少—蜡质晶体熔融—表皮"囊状凸起"—表皮膜层破裂。这些结构变化有利于病菌突破角质层屏障而侵入到植株体内。色质谱分析结果显示:与野生型相比,cer1突变体烷、次级醇、酮类显著减少;cer4突变体表现为一级醇含量减少。接种核盘菌后,野生型拟南芥与蜡质突变体一级醇类显著增加(cer1增加不显著);烷类、次级醇类、酮类含量与蜡质总量均显著减少,表明蜡质前体物质在受到核盘菌胁迫后更多地通过酰基还原途径生成一级醇,从而减少了由脱羰基途径所生成的蜡质组分。核盘菌通过改变表皮蜡质晶体结构与化学组分分泌量来促进侵染。  相似文献   
3.
Waxes are components of the cuticle covering the aerial organs of plants. Accumulation of waxes has previously been associated with protection against water loss, therefore contributing to drought tolerance. However, not much information is known about the function of individual wax components during water deficit. We studied the role of wax ester synthesis during drought. The wax ester load on Arabidopsis leaves and stems was increased during water deficiency. Expression of three genes, WSD1, WSD6 and WSD7 of the wax ester synthase/diacylglycerol acyltransferase (WS/DGAT or WSD) family was induced during drought, salt stress and abscisic acid treatment. WSD1 has previously been identified as the major wax ester synthase of stems. wsd1 mutants have shown reduced wax ester coverage on leaves and stems during normal or drought condition, while wax ester loads of wsd6, wsd7 and of the wsd6wsd7 double mutant were unchanged. The growth and relative water content of wsd1 plants were compromised during drought, while leaf water loss of wsd1 was increased. Enzyme assays with recombinant proteins expressed in insect cells revealed that WSD6 and WSD7 contain wax ester synthase activity, albeit with different substrate specificity compared with WSD1. WSD6 and WSD7 localize to the endoplasmic reticulum (ER)/Golgi. These results demonstrated that WSD1 is involved in the accumulation of wax esters during drought, while WSD6 and WSD7 might play other specific roles in wax ester metabolism during stress.  相似文献   
4.
Green gram, Vigna radiata (L.) Wilczek, is an important pulse crop of Asia. Severe attack by the larvae of Spilosoma obliqua Walker (Lepidoptera: Arctiidae) causes defoliation of green gram and reduces seed yield. Females lay eggs on the leaf surface, and therefore, surface wax plays an important role as short-range attractant and oviposition stimulant. So, we have attempted to find out whether leaf surface wax compounds (alkanes and free fatty acids) from three green gram cultivars (PDM 54, PUSA BAISAKHI and SAMRAT) could act as short-range attractant and oviposition stimulant in females. The TLC, GC-MS and GC-FID analyses of n-hexane extracts revealed 20 n-alkanes from n-C15 to n-C36 and 13 free fatty acids from C12:0 to C21:0, whilst linoleic acid was unique in SAMRAT. Pentacosane was the predominant amongst n-alkanes in the leaf surface waxes of three cultivars. Heneicosanoic acid and palmitoleic acid were the predominant free fatty acids in the leaf surface waxes of PDM 54, and PUSA BAISAKHI and SAMRAT, respectively. Females were attracted towards one leaf equivalent surface wax of three green gram cultivars against solvent controls (n-hexane) in Y-tube olfactometer bioassays. A synthetic blend of pentacosane, heptacosane, nonacosane, hexatriacontane, palmitoleic acid, linolenic acid and stearic acid, a synthetic blend of pentacosane, hexatriacontane and stearic acid, and a synthetic blend of hexatriacontane, linolenic acid and stearic acid resembling in amounts present in one leaf equivalent surface wax of PDM 54, PUSA BAISAKHI and SAMRAT, respectively, served as short-range attractant and oviposition stimulant in females. Females showed equal preference for egg laying towards the above three synthetic blends when these blends were tested against each other, and hence, these blends could be employed in development of baited traps in pest management strategies.  相似文献   
5.
Mobilities of lipophilic organic solutes in cuticular membranes (CM) isolated from mature leaves of Citrus aurantium L., Citrus grandis L., Hedera helix L., IIex aquifolium L., Ilex paraguariensis St.-Hil., Mains domestica Borkh., Prunus armeniaca L., Primus laurocerasus L., Pyrus communis L., Pyrus pyrifolia (Burm. f.) Nakai, Stephanotis florihunda Brongn. and Strophantus gratus Baill. were measured over a temperature range of 15–78°C. In this range, solute mobilities increased up to 1000-fold, which corresponds to temperature coefficients Q10 of 3 (IAA in P. armeniaca) to 14 (cholesterol in H. helix). For most species, Arrhenius graphs showed good linearity up to 40°C, and up to 78°C for some species, while for others activation energies declined with increasing temperature. However, no distinct phase transitions caused by sudden structural changes in the CM were observed. In three species we examined whether heating to 70°C changed solute mobility irreversibly by comparing Arrhenius graphs for two successive experiments with the same CM. The two graphs were very similar for P. laurocerasus, while mobilities in the second graph were somewhat reduced for C. aurantium and greatly increased (at 25 and 35°C) for H. helix. This indicates rearrangements of at least some wax constituents when heated to high temperatures. The activation energies of diffusion (ED) ranged from 75 to 189 KJ mol?11 depending on species and solute size. Size selectivity and variability between cuticles decreased with increasing temperature, and this is caused by differences in (ED). An excellent correlation between the pre-exponential factor of the Arrhenius equation and ED was observed, which is evidence that organic solutes differing greatly in molecular size (130–349 cm3 mol?1) and cuticle/water partition coefficient (25–108) use similar diffusion paths in the CM of all 12 plant species tested. Diffusion occurs in regions with identical physicochemical properties and differs only in magnitude.  相似文献   
6.
M.J.K. Macey 《Phytochemistry》1974,13(8):1353-1358
Two different mutations in Brassica oleracea, gl5 and gl4 have been re-investigated using acetate-1-14C labelling in an attempt to define more closely the nature of the genetic blocks to wax synthesis. It has been found that gl5 is a mutation which blocks elongation in the Step C28–C30. The mutation gl4 exhibits no elongation block and could be blocked in the decarboxylation Step C30–C29. 0·1 mM TCA supplied in the culture solution of cauliflower seedlings affected the leaf surface by producing a glossy appearance similar to that induced by gl3 and gl4. At this concentration growth was not inhibited and the appearance of the plants was normal except for the surface wax. The amount of surface wax produced was about 40% of that in untreated seedlings on a leaf area basis. Slight, but significant changes in wax composition were noted, mainly involving a reduction in C30 acids and aldehydes, a slight reduction (33–29%) in alkane content, and a marked difference in chain length composition of the alkanes with C27 increased relative to C29. Over a range of concentrations from 0·1–1 mM, TCA inhibited incorporation of label from acetate-1-14C into C30 acids and aldehydes more than into C28 at concentrations 0·4–0·8 mM while label tended to accumulate in C24 and C26 acids; thus elongation C28–C30 was especially sensitive to TCA. TCA also inhibited incorporation into primary alcohols and esters almost as much as into C29 compounds. In spite of relatively specific effects on incorporation of label into longer chain lengths, the resulting block to C30 synthesis is not sufficient to make much difference to the overall rate of C29 synthesis. Both results of analysis of wax from whole plants and experiments with tissue slices in vitro indicated that the effect of TCA in reducing the glaucousness of the leaf surface is a combination of overall reduction of wax synthesis together with slight but significant changes in wax composition.  相似文献   
7.
Two Italian CO2 springs allowed us to study the long-term effect of a 350–2600 μ mol mol–1 increase in CO2 concentrations on the surface structures of leaves of Quercus ilex L. Carbon dioxide increased the quantity of cuticular waxes, above an apparent threshold of 750 μ mol mol–1 CO2. Leaf wettability was not modified by CO2 concentrations. Reduction in stomatal frequency was observable up to 750 μ mol mol–1 CO2, the slope being almost the same as that estimated for the increase in CO2 concentration from pre-industrial times to the present. At higher concentrations, CO2 seemed to exert no more impact on stomatal frequency.  相似文献   
8.
Leaf architecture and epidermal characters in Zelkova, Ulmaceae   总被引:4,自引:0,他引:4  
Zelkova , with six extant species in Eurasia - three in East Asia (Z. schneideriana, Z. serrata, Z. sinica) , one in south-western Asia (Z. carpinifolia) and two in southern Europe (Z. abelicea, Z. sicula) - was investigated with respect to leaf architecture and epidermal characters by LM and SEM. The leaf venation of Zelkova is relatively uniform, while leaf size and shape are highly variable. Characters such as teeth and epidermal cells, trichomes and stomata provide useful specific distinctions. Beginning in the Miocene, increasing aridity in Central Asia would appear to have been responsible for isolating the eastern Asiatic species from their European/western Asiatic counterparts. The European range underwent further changes in response to Quaternary climatic oscillations.  相似文献   
9.
10.
Nicotine inhibits carotenoid cyclization in greening cucurbit cotyledons resulting in the accumulation of acyclic and monocyclic carotenes. Chlorophyll synthesis is also inhibited by the alkaloid.  相似文献   
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