不同生育期水分胁迫对水稻根叶渗透调节物质变化的影响

 干旱是限制水稻(Oryza sativa)作物产量的主要生态因子之一,渗透调节是作物适应干旱逆境的生理机制之一。在人为控制水分的盆栽条件下, 对水稻生长的分蘖期、幼穗分化期、抽穗期、结实期分别进行水分胁迫,研究水稻根系及叶片渗透调节物质的变化规律。结果表明, 不同生育期 干旱胁迫后叶片水势均显著下降,根系和叶片的有机渗透调节物质如可溶性糖、游离氨基酸、脯氨酸和无机渗透调节物质包括K⁺、Mg²⁺等含量 均大幅度上升,而且幼穗分化期和抽穗期这两个对水分胁迫最敏感的时期上升幅度最大,其中又以有机渗透调节物质变化最显著。不同生育期渗 透调节大小的顺序为：抽穗期>幼穗分化期>结实期>分蘖期,反映了不同生育时期渗透调节能力的差异。同时幼穗分化期和抽穗期水分胁迫结束 后再复水后根系和叶片的有机渗透调节物质含量仍长期明显高于对照,而无机离子则变化规律比较复杂,有的升高有的则降低。叶片的渗透调 节能力大于根系,无论是叶片或根系都是K⁺对渗透调节的贡献最大;其次是Ca²⁺, 6 种渗透调节物质含量大小排列顺序为K⁺ > Ca²⁺ >可溶性糖 > Mg²⁺ > 游离氨基酸 > 脯氨酸。     

土壤缓慢脱水对开花期小麦根系及叶片渗透调节及渗透调节物质的影响

以抗旱性不同的小麦品种为材料,在小麦的水分临界期开花期进行缓慢脱水处理,分别在脱水的不同阶段取样测定叶片及根系的渗透调节能力及渗透调节物质。结果表明：随着土壤含水量的降低,叶片与根系的饱和渗透势同步下降,表现出叶片与根系对水分胁迫反应的一到场生,但根系的渗透调节能力低于叶片。根系与叶片的渗透调节物质,一方面在物质总含量方面,表现出与渗透调节能力的一致性,另一方面各种物质的相对含量又有一定差异,叶片中可溶性糖与K＋含量及增加量都高于根系,而根系中的游离氨基酸与Ca^2 的相对增加量则大于叶片。     

水分胁迫对牛心朴子植株生长及渗透调节物质积累的影响

采用PVC管种植模拟土壤干旱的方法,研究了牛心朴子(Cymanchum komarovii)在水分胁迫下植株生长及渗透调节物质的积累情况。结果表明：牛心朴子植株地上部对土壤水分比较敏感,随水分胁迫程度的加强和胁迫时间的延长,植株生长显著变缓,直至停止生长,而根／冠比值则有所加大;可溶性糖是牛心朴子根系主要的渗透调节物质,随着土壤水分胁迫程度的加重,根系中的可溶性糖呈明显的增加趋势,叶中的可溶性糖则随胁迫的加重而呈下降趋势,说明在干旱胁迫下牛心朴子的同化产物大部分分配于根系之中;Pro在牛心朴子叶、茎、根的渗透调节中也起着重要作用,随土壤水分胁迫的加重,其在根、茎、叶中的积累明显增加;而无机离子在牛心朴子渗透调节过程中的作用很小。     

土壤缓慢脱水对开花期小麦根系及叶片渗透调节及渗透调节物质的影响

以抗旱性不同的小麦品种为材料,在小麦的水分临界期开花期进行缓慢脱水处理,分别在脱水的不同阶段取样测定叶片及根系的渗透调节能力及渗透调节物质。结果表明：随着土壤含水量的降低,叶片与根系的饱和渗透势同步下降,表现出叶片与根系对水分胁迫反应的一致性,但根系的渗透调节能力低于叶片。根系与叶片的渗透调节物质,一方面在物质总含量方面,表现出与渗透调节能力的一致性,另一方面各种物质的相对含量又有一定差异,叶片中可溶性糖与K+的含量及增加量都高于根系,而根系中的游离氨基酸与Ca2+的相对增加量则大于叶片。     

长期水分胁迫对小麦生育中后期根叶渗透调节能力、渗透调节物质的影响

以 2个抗旱性强的和 2个抗旱性弱的小麦品种为材料 ,研究了中度及严重水分胁迫对根系及叶片渗透调节能力的影响。结果表明 :随着水分胁迫的加剧 ,叶片的渗透调节能力增强 ,但在籽粒迅速扩大的灌浆期 ,叶片的渗透调节能力下降。去穗处理明显地提高叶片的渗透调节能力。说明叶片渗透调节能力的高低与同化物的供应及分配有关。不同品种根系渗透调节能力与叶片基本一致 ,但根系的渗透调节能力低于叶片。开花、灌浆期根系的渗透调节能力大大降低 ,严重水分胁迫下根系的渗透调节能力低于中度水分胁迫。这一方面与同化物的供应有关 ,另一方面严重水分胁迫还会对根细胞造成损伤 ,对根系的渗透调节能力产生影响。渗透调节物质的变化趋势与渗透调节能力基本一致。叶片中 K+对渗透调节的贡献最大 ;其次是可溶性糖 ,6种渗透调节物质排列顺序为 K+>可溶性糖 >游离氨基酸 >Ca2 +>Mg2 +>Pro。根系中仍以 K+占绝大部分 ,但根系中 Ca2 +也是不可忽视的成分之一。     

水分胁迫对燕麦穗颖渗透调节和抗氧化能力的影响

以抗旱性不同的燕麦品种‘蒙燕1号’(抗旱性强)和‘坝莜3号’(水分敏感)为试验材料,采用盆栽方式研究了抽穗期和灌浆期水分胁迫对燕麦穗颖渗透调节和抗氧化能力的影响。结果表明:(1)水分胁迫处理均显著促进了不同抗旱性品种穗颖渗透调节物质(游离脯氨酸和可溶性蛋白)含量增加,并以抗旱品种累积水平高于水敏感品种,且两种渗透调节物质对抽穗期胁迫的反应比灌浆期胁迫更敏感。(2)两时期的水分胁迫处理均能降低不同抗旱性品种穗颖SOD和POD活性,抗旱品种的保护酶活性要高于水敏感品种,抗旱品种的SOD活性降低幅度明显低于水敏感品种,而POD活性降低幅度在两品种间差异不明显。(3)水分胁迫导致2个品种穗颖丙二醛(MDA)含量和相对电导率显著增加,细胞膜结构受到严重伤害,且水敏感品种受害程度大于抗旱品种。(4)水分胁迫使2个品种单株籽粒产量下降,且在中度胁迫和重度胁迫下,抗旱品种的减产幅度要低于同期水敏感品种;水分胁迫下,水敏感品种‘坝莜3号’减产4.54%~30.29%,抗旱品种‘蒙燕1号’减产6.69%~23.54%。可见,抗旱性强的燕麦品种在受到水分胁迫的条件下能通过增强穗颖渗透调节和抗膜质过氧化能力、减弱穗颖细胞质膜损伤程度来适应干旱胁迫,最大限度减少水分胁迫对穗颖的伤害,有利于稳产。     

干旱胁迫对甘草幼苗生长和渗透调节物质含量的影响

采用人工控制水分模拟干旱的处理方法,研究了干旱胁迫对甘草幼苗生长状况、水分状况和主要渗透调节物质含量的影响.结果显示:轻度干旱胁迫有利于甘草幼苗根系生长,植株根冠比加大.干旱胁迫下甘草根叶组织中相对含水量下降,束缚水/自由水升高.甘草幼苗组织中渗透调节物质可溶性蛋白、游离脯氨酸、可溶性糖含量在干旱胁迫下也均显著增加;且...     

土壤干旱对黄土高原乡土树种水分代谢与渗透调节物质的影响

以黄土高原4个乡土树种的幼苗为试验材料,采用盆栽方式模拟土壤干旱环境,研究土壤干旱对不同树种水分代谢与渗透调节物质的影响。结果表明,大叶细裂槭、虎榛子叶水势、叶片含水量下降迅速,叶片离体保水能力降幅明显;白刺花、辽东栎则表现为叶水势、叶片含水量缓慢下降,组织相对含水量在中度胁迫下略有上升。白刺花在不同水分处理条件下离体叶片保水力明显高于其它树种。1个树种可溶性糖含量随土壤干旱程度加剧明显增加,可溶性蛋白质含量在树种之间变化较为复杂,无明显规律性。K^ 离子含量和游离脯氨酸含量在中度水分胁迫下均有不同程度升高。白刺花在土壤干旱进程中,可溶性蛋白质含量、K^ 离子含量和游离脯氨酸含量均明显高于其它树种。综合水分代谢和渗透调节物质来看,水分胁迫条件下,白刺花以保持高水势、减少组织水分散失和增加渗透调节物质来提高细胞原生质浓度,增强其抗旱性。     

半根和全根干旱对嘎拉苹果组培苗渗透调节物质积累的影响

以1年生苹果组培苗为试验材料,用改良的Hoagland营养液加20％聚乙二醇6000进行半根渗透胁迫（HRS）处理,与全根渗透胁迫（WRS）和只加营养液的对照（CK）进行比较,研究了根系不均匀供水条件下植株的叶片水势、脯氨酸、游离氨基酸、町溶性糖、淀粉等几种有机溶质,以及Na^-、K^-、Mg^2＋、Ca^2＋、Cl^-、SO4^2-、NO3^-等无机离子的含量变化特点。结果表明,HRS与CK之问叶片的日出前水势不存在显著差异,但显著高于WRS。叶片的日出前水势与叶片中脯氨酸和可溶性糖含量之间呈负相关关系,与淀粉含量之问呈正相关关系,与Na^-、K^-、Mg^2＋、Ca^2＋、Cl^-、SO4^2-、NO3^-之间没有相关关系。表明干旱胁迫后苹果幼苗叶片中脯氨酸等有机溶质参与渗透调节作用,无机离子的作用较小。HRS叶片中有机溶质没有大量积累,表明HRS植株整体的水分供应状况良好。     

荒漠绿洲过渡带一年生草本植物对干旱胁迫的响应

选取河西走廊荒漠绿洲过渡带典型一年生草本植物雾冰藜（Bassia dasyphylla）、虎尾草（Chloris virgata）和狗尾草（Setaria viridis）为研究对象,设置5个水分梯度（正常水分（CK）,轻度干旱（5d）、中度干旱（10d）、重度干旱（15d）,重度干旱（15d）复水）,分析了3种一年生草本植物生理和形态等性状对干旱胁迫的响应。结果表明：一年生草本植物可以通过生理反应（渗透调节）适应轻度和中度干旱胁迫,而通过个体形态来适应重度干旱胁迫。在轻度和中度干旱处理下,一年生草本植物通过调控叶片渗透调节物质脯氨酸、可溶性蛋白和可溶性糖维持叶片渗透压,提高保水能力,叶绿素含量增加,使丙二醛含量维持在较低的水平,同时,根系活力增强,有效促进了根系水分吸收;而在重度胁迫下,渗透调节物质作用降低,丙二醛含量迅速增加,导致可溶性蛋白含量下降,叶绿素分解加速,植物生长受到抑制,在有限的生物量下,一年生草本植物主要通过根系伸长、根长与茎长的比增加和减小茎长来适应重度干旱胁迫,最终导致了种子百粒重和结种数量下降。     

壳聚糖酶的克隆表达与壳寡糖的制备分析

目的:克隆壳聚糖酶基因于大肠杆菌中实现高表达,制备壳寡糖。方法:以枯草芽孢杆菌总DNA为模板扩增壳聚糖酶基因(CSN),克隆至载体pET23a(+)上,转化菌株BL21(DE3)。重组子经0.5 mmol/L IPTG诱导后,SDS-PAGE和质谱检测与鉴定重组酶。酶纯化后水解壳聚糖,薄层色谱分析其水解产物。结果:质谱证明壳聚糖酶(31.5kDa)成功表达,表达量占菌体总蛋白的45%左右。纯化后重组酶浓度为900 mg/L,纯度95%、回收率85%,酶活力为10 000 U/mg。壳聚糖降解产物为壳二糖至壳四糖。结论:原核表达载体pET23a(+)-CSN构建正确,壳聚糖酶表达量与活性高,适用于水解壳聚糖制备壳寡糖。     

国内外蝗害治理技术现状与展望

本文首先概述了国内外蝗虫发生与为害的态势,总结了现阶段我国蝗虫发生与为害的主要特点:即农田飞蝗暴发频繁而且严重,草原土蝗的发生时常造成严重的经济损失,而且侵入城市干扰市民生活,我国与周边国家之间蝗虫过境迁移频繁,使用化学农药污染环境和农产品;分析了国内外蝗虫防治对策与技术的发展现状,重点介绍了应急防治和可持续治理对策、...     

Comparison of BMI and percentage of body fat of Indian and German children and adolescents

Today, serious health problems as overweight and obesity are not just constricted to the developed world, but also increase in the developing countries (Prentice 2006, Ramachandram et al. 2002). Focusing on this issue, BMI and percentage of body fat were compared in 2094 schoolchildren from two cross-sectional studies from India and Germany investigated in 2008 and 2009. The German children are in all age groups significantly taller, whereas the Indian children show higher values in BMI (e.g. 12 years: Indian: around 22 kg/m2; German: around 19 kg/m2) and in the percentage of body fat (e.g. 12 years: Indian: around 27%; German: around 18-20%) in most of the investigated age groups. The Indian children have significantly higher BMI between 10 and 13 (boys) respectively 14 years (girls). Indian children showed significant higher percentage of body fat between 10 and 15 years (boys) and between 8 and 16 years (girls). The difference in overweight between Indian and German children was strongest at 11 (boys) and 12 (girls) years: 70% of the Indian but 20% of the German children were classified as overweight. In countries such as India that undergo nutritional transition, a rapid increase in obesity and overweight is observed. In contrast to the industrialized countries, the risk of overweight in developing countries is associated with high socioeconomic status. Other reasons of the rapid increase of overweight in the developing countries caused by different environmental or genetic factors are discussed.     

Synthesis and turnover of cerebrosides and phosphatidylserine of myelin and microsomal fractions of adult and developing rat brain.

The synthesis and turnover of cerebrosides and phospholipids was followed in microsomal and myelin fractions of developing and adult rat brains after an intracerebral injection of [U-14C]serine. The kinetics of incorporation of radioactivity into microsomal and myelin cerebrosides indicate the possibility of a precursor-product relationship between cerebrosides of these membranes. The specific radioactivity of myelin cerebrosides was corrected for the deposition of newly formed cerebrosides in myelin. Multiphasic curves were obtained for the decline in specific radioactivity of myelin and microsomal cerebrosides, suggesting different cerebroside pools in these membranes. The half-life of the fast turning-over pool of cerebrosides of myelin was 7 and 22 days for the developing and adult rat brain respectively. The half-life of the slowly turning-over pool of myelin cerebrosides was about 145 days for both groups of animals. The half-life of the rapidly turning-over microsomal cerebrosides was calculated to be 20 and 40 h for the developing and adult animals respectively. The half-life of the intermediate and slowly turning-over microsomal cerebrosides was 11 and 60 days respectively, for both groups of animals. The amount of incorporation of radioactivity into microsomal cerebrosides from L-serine was greatly decreased in the adult animals, and greater amounts of the precursor were directed towards the synthesis of phosphatidylserine. In the developing animals, considerable amounts of cerebrosides were synthesized from L-serine, besides phosphatidylserine. The time-course of incorporation indicated that a precursor-product relationship exists between microsomal and myelin phosphatidylserine. The half-life of microsomal phosphatidylserine was calculated to be about 8 h for the fast turning-over pool in both groups of animals.     

Identification and composition of the tonsillar and anal enterococcal and streptococcal flora of dogs and cats

Enterococcus faecalis was the most frequently isolated enterococcal species from anal swabs and tonsils of dogs and cats, although in the anal samples from dogs Ent. hirae was found almost as often as Ent. faecalis. Most Ent.faecium strains from dog tonsils differed from those associated with humans and other animals in that they fermented sorbitol. Typical Ent. avium as well as atypical Ent. avium -like strains were seen in dogs, while the related species Ent. raffinosus was associated with cat tonsils. Enterococcus cecorum also occurred mainly in cats. Certain atypical strains, presumptively identified as Ent. cecorum , shared characteristics with Ent. columbae.
The most frequent streptococcal species in tonsils of cats and dogs were Streptococcus suis and Strep. canis. Streptococcus canis and Strep. bovis predominated in anal swabs. The canine Strep. suis differed from the common porcine strains in fermenting mannitol.
Forty-seven of the 288 isolates examined could not be identified or related to known species. The characteristics of two groups of these bacteria, provisionally called 'Ton 31 group' and 'O7 group' are described.     

颧骨颧弓骨折的分类及诊治

颧骨颧弓骨折是最常见的面中部骨折之一,迄今为止,在其分类及诊治的选择上仍然存在一定争议,本文对目前颧骨颧弓骨折的分类及诊治的现状和进展作一综述,以期对临床工作提供参考。