硫灯和氙灯下生长的黄瓜幼苗植物激素水平的差异

就人工气候室两种光源硫灯和氙灯引起黄瓜幼苗生长差异的原因进行了初步探讨.与生长在氙灯下的幼苗相比,硫灯下生长的幼苗较矮.组织细胞观察显示,硫灯下生长的黄瓜幼苗中胚轴表皮和皮层细胞纵向单位毫米长度所含细胞数目比氙灯下多.内源激素分析结果表明,硫灯下生长的黄瓜幼苗内源激素吲哚乙酸(IAA)和赤霉素(GA3)含量较氙灯下分别低17%和24%,而脱落酸(ABA)含量高31%.推测硫灯和氙灯下黄瓜幼苗生长的差异可能与内源激素调控有关.     

不同红光/远红光比例(R/FR)的光照影响番茄幼苗叶片中花青素合成的研究

硫灯或氙灯具有不同的红光／远红光比例(R／FR,前者为1．5,而后者为1)。研究结果表明,硫灯照射下生长的番茄幼苗叶片与太阳光下相似,能正常合成花青素;而氙灯照光生长的番茄幼苗叶片中的花青素合成受到严重抑制,通过分光光度法测定的花青素含量仅为前者的1／9。进一步在硫灯下培养红光／远红光受体(光敏素B族)单突变和双突变的番茄幼苗中,发现单突变体phyB1和双突变体phyB1phyB2的叶片花青素含量显著低于野生型,分别为野生型的1／3和1／15,由此推测花青素合成途径受到了红光／远红光比例的影响。HPLC结果又表明,硫灯和氙灯照光生长的番茄幼苗叶片中黄酮醇总量没有显著差异。我们推测氙灯下番茄幼苗花青素合成过程可能抑制位点是二氢黄酮醇还原酶或白花色素双氧酶两个催化步骤。     

以国产氙灯代替进口氙灯

氙灯能辐射从紫外到近红外的连续光谱,是一种很好的光源。但氙灯的寿命一般比氢灯和汞灯短,大约为500小时左右。但是实际上由于各种原因,很多氙灯的寿命大大低于这个值。在我们的工作中就遇到过:氙灯只用了50小时,由于极度不稳定,影响测定稳定性,只能更换。     

紫外线照射对玫烟色拟青霉产孢子能力的影响

目的:探讨紫外线照射对玫烟色拟青霉产孢子能力的影响.方法:利用20W紫外 灯对玫烟色拟青霉的原生质体悬浮液进行了不同照射时间、对孢子悬浮液进行了不同照射距 离和时间组合的紫外线照射处理.结果:紫外灯下30cm照射原生质体90 s及紫外灯下20cm照射孢子20min两个处理中,菌落直径最大菌株的菌丝生长速度显著高于出 发菌株,产孢量也分别是出发菌株的1.4及1.6倍.结论:适宜的紫外线照射处理可以提高玫烟色拟青霉的产孢子能力.     

激光预处理可保护蚕豆细胞免受UV—B辐射的损伤

当蚕豆的胚被 He- Ne激光 (632 .8nm,1 .63J· mm- 2 )照射 5min或被 CO2 激光 (1 0 60nm,2 .53J· mm- 2 )照射 1 min后 ,将其置入 Knop营养液中进行恒温培养。当蚕豆的上胚轴长到大约 3cm时 ,在光背景 (PAR)为 70μmol· m- 2 · s- 1条件下 ,分别用 1 .0 2、3.0 3、4.52 k J· m- 2 的 UV- B辐射蚕豆的上胚轴 7h。根据蚕豆丙二醛 (MDA)、抗坏血酸 (As A)和 UV- B吸收物的含量变化 ,来测试激光对 UV- B照射蚕豆的上胚轴的保护作用。结果显示 :激光预处理可保护蚕豆上胚轴对 UV- B辐射的作用。与对照组 (没有用 UV- B或激光照射 )、UV- B单独照射组比较 ,在激光预处理的条件下 ,MDA的含量明显减少 ,As A和 UV- B吸收化合物的含量增加。如先用激光处理 ,然后再用 UV- B辐射 ,UV- B吸收物的含量将比单独用激光和 UV-B处理获得更好的改善。从而认为 ,激光预处理能增强植物对 UV- B的抵抗力。     

Trichilia dregeana胚轴的脱水敏感性与抗坏血酸的抗氧化作用

以顽拗性Trichilia dregeana Sond.种子为材料,研究其胚轴的脱水敏感性与抗坏血酸的抗氧化作用.T.dregeana胚轴的脱水耐性随着脱水进程逐渐下降,50%的胚轴被脱水致死的含水量(W50)大约为0.16 g H2O/g DW.在脱水过程中,胚轴的电解质渗漏速率逐渐增加,超氧物歧化酶(SOD)、抗坏血酸过氧化物酶(APX)、过氧化氢酶 (CAT)、谷胱苷肽还原酶(GR)和脱氢抗坏血酸还原酶(DHAR)的活性下降,硫代巴比妥酸(TBA)-活性产物的含量增加.2.5～10.0 mmol/L抗坏血酸处理能有效地增加胚轴的脱水耐性和SOD、APX、CAT和GR的活性,降低电解质渗漏速率和TBA活性产物的含量.结果表明,T.dregeana胚轴的脱水耐性与抗氧化酶的活性增加和脂质过氧化作用的降低密切相关.     

Trichiliadregeana胚轴的脱水敏感性与抗坏血酸的抗氧化作用

以顽拗性TrichiliadregeanaSond.种子为材料,研究其胚轴的脱水敏感性与抗坏血酸的抗氧化作用。T.dregeana胚轴的脱水耐性随着脱水进程逐渐下降,50%的胚轴被脱水致死的含水量(W50)大约为0.16gH2O/gDW。在脱水过程中,胚轴的电解质渗漏速率逐渐增加,超氧物歧化酶(SOD)、抗坏血酸过氧化物酶(APX)、过氧化氢酶(CAT)、谷胱苷肽还原酶(GR)和脱氢抗坏血酸还原酶(DHAR)的活性下降,硫代巴比妥酸(TBA)-活性产物的含量增加。2.5~10.0mmol/L抗坏血酸处理能有效地增加胚轴的脱水耐性和SOD、APX、CAT和GR的活性,降低电解质渗漏速率和TBA活性产物的含量。结果表明,T.dregeana胚轴的脱水耐性与抗氧化酶的活性增加和脂质过氧化作用的降低密切相关。     

MPF-4型荧光分光光度计中氙灯电源的维修

日立MPF-4荧光分光光度计中的氙灯电源,使用数年后常出现脉冲变压器击穿,线组短路和绝缘度下降致使氙灯不能触发点燃等故障。为帮助从事这方面工作的人员,分析故障原因,找出解决办法,现将我们维修这种电源的经验介绍如下。一、MPF-4氙灯电源工作原理 1.电源工作原理,可参看《介绍一种定量分析用氙灯稳流电源》一文(本刊1980年第6期70页) 二、MPF-4氙灯电源故障修理 1.故障原因分析 MPF-4荧光分光光度计电源在点燃系统中采用特殊电路,和其它仪器     

毒死蜱在水溶液中的光化学降解

研究了不同光源、水溶液温度、pH、水质对毒死蜱在水溶液中光化学降解的影响.结果表明,毒死蜱在水溶液中的光解均呈一级动力学反应;毒死蜱水溶液分别在高压汞灯、紫外灯、氙灯、太阳光照射下,光解速度存在明显差异,其光解半衰期分别为0.62、6.92、19.74和22.50 h;温度对毒死蜱光降解影响显著,温度升高,光解速度加快,当温度升高到35 ℃,光解速率达到最大;毒死蜱在酸性至中性缓冲液中光解速度稳定,在碱性缓冲液中光解速度加快;不同水质对毒死蜱光解的影响差异较显著,毒死蜱光解速率大小表现为蒸馏水＞塘水＞河水＞湖水＞稻田水.     

问题解答

问:怎样理解"子叶以下的胚轴"?答:初中《植物学》第26页,以大豆和豌豆为例说明双子叶植物的种子在萌发时,有的种子的子叶出土,有的种子的子叶则不出土,常以"子叶以下的胚轴"不伸长为由.胚轴位于胚根和胚芽之间,同时与子叶相连,从子叶着生点至第一片真叶的一段称上胚轴,从子叶着生点至根的一段称下胚轴.书上说的"子叶以下的胚轴"就是指的下胚轴.但是,我们认为:"子叶以下的胚轴"的提法不妥,它容易使人混淆概念,以为胚轴完全处于子叶     

光对棉铃虫和烟青虫杂交的影响

【目的】力求建立一种准确鉴定室内棉铃虫Helicoverpa armigera(Hübner)、烟青虫H.assulta(Guenée)及其杂交种的分子技术,探讨棉铃虫和烟青虫杂交的可能。【方法】室内暗期设置0.5 lx黑光灯和白炽灯,测定不同配对模式下3日龄处女棉铃虫和烟青虫的杂交率;筛选可区分室内建立的棉铃虫、烟青虫及杂交种家族的微卫星位点;于架设有黑光灯的温室内释放棉铃虫和烟青虫混合种群,利用微卫星分子标记技术检测子代微卫星位点大小。【结果】两种蛾类在任何一种配对模式下均可杂交,混合种群处理杂交率为2.92%,且均为烟青虫雌蛾与棉铃虫雄蛾配对交配;黑光灯、白炽灯和黑暗条件下杂交率无显著性差异;筛选出的Har SSR1、Har SSR9和Har SSR10在两种蛾类上的等位基因片段大小不一样;两年温室实验共鉴定360头子代,混合种群中未检测到杂交后代。【结论】交配笼中棉铃虫和烟青虫能进行种间杂交,弱光不能提高二者杂交率;混合种群处理只发现一种杂交配对模式,说明了棉铃虫雄蛾的交配竞争能力更强;成功利用微卫星分子标记技术鉴定室内建立的棉铃虫、烟青虫及杂种家族,提供了一种简单准确的分子鉴定手段;两年温室实验未检测到杂交种,说明2种蛾类之间存在着交配前生殖隔离机制。     

丁草胺在不同类型水中的光化学降解

研究了除草剂丁草胺在氙灯、高压汞灯光照下的光解动态。结果表明,丁草胺在氙灯光照作用下,其光解速率为纯水>河水>塘水>稻田水;丁草胺在氙灯光源下的光解速度比高压汞灯下低;其光解率与浓度(剂量)呈反相关;充N₂脱O₂使丁草胺的光解速度减缓。     

Growth Chamber Illumination and Photomorphogenetic Efficacy I. Physiological action of infrared radiation beyond 750 nm

Plants cultivated in growth chambers under such artificial illumination as fluorescent tubes show certain characteristic differences from plants grown in nature or under incandescent lamps. The plants grown under fluorescent light are shorter and more darkly pigmented; they also show different daylength requirements for certain photoperiodic responses. It was assumed that these effects were caused by the relative deficiency of far red irradiation (λ= 700–750 nm) in the emission from the fluorescent lamps. This assumption was tested on such light sensitive phenomena as stem elongation, flowering, the formation of resting organs, chlorophyll synthesis, and production yield in several plant genera. In all cases the plants were grown under long days (16 h). Six common types of growth chamber illumination were tested for their efficacy for long-day induction. The spectral energy distribution of the lamps was measured. The emission from the various lamp types showed only small differences within the region of visible light (λ: 400–750 nm), but much larger diversity in the ratio of visible to infrared radiation (λ: 750–1000 nm). A strong correlation exists between the relative emission of infrared radiation and the photomorphogenetic efficacy of the lamps. Under fluorescent light the long-day effect was weak or missing, but increased with increasing infrared emission. High infrared emission was also favourable for high production yield.     

性诱盆与频振灯在棉铃虫成虫动态监测中的作用比较

20 0 1年在南疆棉区做了性信息素水盆诱捕器 (性诱盆 )和频振式杀虫灯 (频振灯 ,3 0W)对棉铃虫成虫诱捕效率的对比试验。结果表明 ,6个监测点平均 ,每日每只性诱盆和频振灯的诱蛾量分别为3 5 .4和 3 2 .3头 ,差异不显著 (P >0 .0 5 )。在 1代成虫盛发的前期和中后期 ,性诱盆相对于频振灯的诱蛾量有先低后高的现象。考虑到经济性和可识别性等因素 ,作者认为在南疆监测棉铃虫成虫动态性诱盆优于频振灯     

重点单项诱杀措施复合配置对棉铃虫的诱杀效果及规格比较

不同灯光与性诱剂或杨树枝把的复合配置处理对棉铃虫Helicoverpa armigera成虫均具有较明显的诱杀作用,其各自的田间控制效果各不相同,且明显与棉铃虫田间实际发生的相对程度有关。在一定范围内,棉铃虫发生量大的世代或年份,控制效果较好,发生量超常大时控制效果有所降低。综合分析比较该几种复合配置诱集源处理的诱蛾量、田间百株卵量、幼虫量及其对棉铃虫有效态天敌量的影响等因素,结果显示：在不同灯光与性诱剂或杨树枝把的复合配置处理中,以高压汞灯和性诱剂复配效果最好,双波灯与性诱剂的复配效果稍差。高压汞灯与性诱剂、双波灯与性诱剂复配处理区的百株卵量在160 m内分别比对照降低34.5%、28.6%。性诱剂宜设置于高压汞灯区外围80—160 m外,以形成两者空间和时间上的互补。     

GhXB38D represses cotton fibre elongation through ubiquitination of ethylene biosynthesis enzymes GhACS4 and GhACO1

Ethylene plays an essential role in the development of cotton fibres. Ethylene biosynthesis in plants is elaborately regulated by the activities of key enzymes, 1-aminocyclopropane-1-carboxylate oxidase (ACO) and 1-aminocyclopropane-1-carboxylate synthase (ACS); however, the potential mechanism of post-translational modification of ACO and ACS to control ethylene synthesis in cotton fibres remains unclear. Here, we identify an E3 ubiquitin ligase, GhXB38D, that regulates ethylene biosynthesis during fibre elongation in cotton. GhXB38D gene is highly expressed in cotton fibres during the rapid elongation stage. Suppressing GhXB38D expression in cotton significantly enhanced fibre elongation and length, accompanied by the up-regulation of genes associated with ethylene signalling and fibre elongation. We demonstrated that GhXB38D interacts with the ethylene biosynthesis enzymes GhACS4 and GhACO1 in elongating fibres and specifically mediates their ubiquitination and degradation. The inhibition of GhXB38D gene expression increased the stability of GhACS4 and GhACO1 proteins in cotton fibres and ovules, resulting in an elevated concentration of ethylene. Our findings highlight the role of GhXB38D as a regulator of ethylene synthesis by ubiquitinating ACS4 and ACO1 proteins and modulating their stability. GhXB38D acts as a negative regulator of fibre elongation and serves as a potential target for enhancing cotton fibre yield and quality through gene editing strategy.     

Functional analysis of the <Emphasis Type="Italic">BIN2</Emphasis> genes of cotton

Brassinosteroids (BR) promote the elongation of cotton fibers and may be a factor in determining their final length. To begin to understand the role of BR-mediated responses in the development of cotton fibers we have characterized the BIN2 genes of cotton. BIN2 is a member of the shaggy-like protein kinase family that has been identified as a negative regulator of BR signaling in Arabidopsis. Sequence analyses indicate that the tetraploid cotton genome includes four genes with strong sequence similarity to BIN2. These genes fall into two distinct subclasses based on sequence and expression patterns. Sequence comparisons with corresponding genes from cotton species that have the diploid A and D genomes, respectively, shows that each pair of genes comprises homeologs derived from the A and D sub-genomes. Transgenic Arabidopsis plants that express these cotton BIN2 cDNAs show reduced growth and similar phenotypes to the semi-dominant bin2 mutant plants. These results indicate that the cotton BIN2 genes encode functional BIN2 isoforms that can inhibit BR signaling. Further analyses of the function of BIN2 genes and their possible roles in determining fiber yield and quality are underway.