Cold tolerance during early reproductive growth of chickpea (Cicer arietinum L.): genetic variation in gamete development and function

Chilling temperatures at flowering cause floral abortion in most chickpea cultivars. Recent evaluations of germplasm showed distinct genotypic differences in pod and seed set at low temperature but the morpho-physiological basis for such variation is unclear. Observations in the field during cold spells of December and January, and at 15/5°C and 15/0°C (day/night) regimes in growth rooms showed distinct genetic variation in flower morphology, gamete development (viability and size of pollen and ovules) and function (pollen germination and tube growth, ovule viability and fertilization, etc.). The greater pod-setting ability of tolerant lines (ICCVs 88502 and 88503) than the sensitive cultivars (Annigeri, Pant G 114, etc.) was associated with a higher pollen vigour (germination and tube growth) and ovule viability at low temperature in the former. The number of ovules was not affected by cold stress in all cultivars/lines but pollen size and viability were reduced in Annigeri. The reduced ovule fertilization, associated with decline in pollen tube growth and ovule viability, was the major cause for poor seed set at low temperatures. The magnitude of effects on gamete function varied with cultivar/line and severity of stress. Function of both pollen and ovules was adversely affected in Annigeri in 15/5° and 15/0°C regimes. In contrast, the reduction in pollen vigour was more than in ovule viability in ICCV 88510 and Pant G 114 at 15/5°C. At 15/0°C, however, both pollen vigour and ovule viability were reduced. A small increase in pod set of sensitive genotypes from manual pollinations with pollen from plants in the warm regime further suggested that pollen function was more adversely affected than pistil function at moderately low temperatures.     

采后黄瓜响应低温胁迫的转录组学分析

采后黄瓜对低温敏感,在低温贮藏期间很容易发生冷害,会造成较大的采后损失。本研究采用转录组测序结合生物信息学分析的方法,分析了采后黄瓜在短时冷害温度处理后的转录组变化。结果显示,采后黄瓜在5℃贮藏期间,冷害指数和相对电导率逐渐增加,叶绿素荧光逐渐降低,表明采后黄瓜在5℃贮藏期间产生了明显的冷害。与处理前相比（0 h）,处理12 h导致1500个基因差异表达,其中706个基因表达上调,794个基因表达下调。与0 h相比,处理72 h导致7799个基因差异表达,其中3995个基因表达上调,3804个基因表达下调。KEGG富集结果显示,低温处理导致的差异表达基因显著富集在植物激素信号转导、苯丙氨酸代谢、植物与病原菌互作和苯丙烷素合成途径中。GO富集分析的结果显示,在生物过程分类下,差异表达基因主要参与以DNA为模板的转录调控、蛋白磷酸化和跨膜转运等过程;在细胞组份分类下,差异表达基因主要富集在细胞膜组份和细胞核;在分子功能分类下,差异表达基因主要与ATP结合、蛋白苏氨酸/丝氨酸激酶活性、DNA结合和转录因子活性等功能有关。在低温处理12 h时,与激素信号有关的基因显著表达。但在低温处理72 h...     

水杨酸和赤霉素复配剂对低温下玉米光合特性的影响

将水杨酸(SA)和赤霉素(GA)进行复配,研究复配剂(SGM)对田间玉米光合特性的影响。结果表明:SGM处理提高低温胁迫下玉米的生物产量,试验中SGM3(SA0.03%+GA15 mg/L)处理的生物产量比对照高5.04%;拔节期SGM处理的玉米单株叶面积均高于对照,其中SGM3处理的叶面积较对照提高17.42%,达显著水平;SGM处理使玉米幼苗叶片在低温胁迫条件下总叶绿素含量增加,提高低温胁迫条件下玉米幼苗的光合速率;SGM处理可在低温胁迫下保护玉米幼苗叶绿体结构,保持叶绿体超微结构完整,基质片层结构清晰,基粒片层排列整齐。     

Effects of salt and low light intensity during the vegetative stage on susceptibility of rice to male sterility induced by chilling stress during the reproductive stage

We tested whether exposing rice plants to abiotic stress (salt or shade) during vegetative growth affects the chilling tolerance of reproductive organs, which is one of the most important traits for rice growing in a cool climate; we used two rice cultivars with different tolerance in two growing seasons. We divided the vegetative growth into three phases to clarify the most sensitive period: 7–22 days after transplanting (DAT), 23–38 DAT and 39–54 DAT. Chilling tolerance of the pre-stressed plants was based on the male sterility induced by low temperatures. Shade and salt stress during all three vegetative growth phases significantly reduced stomatal conductance. Shade decreased the specific leaf weight and the leaf sugar and starch contents, but salt had no significant effect, despite causing leaf damage. Low temperatures during the reproductive stage induced spikelet sterility in all plants, but the magnitude was greater in the salt- and shade-stressed plants of both cultivars, especially those stressed late during vegetative growth. The increased spikelet sterility caused by chilling was closely related to the reduction of the total spikelet number per panicle. This is the first study to show that salt and low light stress during vegetative growth increased the susceptibility of rice plants to chilling damage during panicle development.     

玉米受精和早期子粒发育过程及逆境胁迫对其影响

玉米受精及子粒发育早期是决定穗粒数及粒重的重要时期,也是对环境变化相对较敏感的阶段。受精极核需要经历游离核、细胞化和细胞分化3个阶段形成胚乳,受精卵同样需要一系列的分裂分化形成最终的胚。玉米受精前极易遭受不良环境的影响,导致性器官发育不正常,影响花粉或花丝活力间接影响玉米受精过程。受精过程中的环境胁迫会通过阻碍花粉与花丝的识别、减缓花粉管在花丝中的延伸速率影响受精过程。子粒发育早期主要是受精极核分裂分化形成胚乳、受精卵分裂分化形成胚的过程,该阶段遭受环境胁迫下,胚乳细胞分裂受阻影响子粒库容。研究表明,逆境胁迫条件下,玉米的受精及子粒早期发育过程与碳水化合物的代谢以及激素的合成密切相关。     

水稻开花期高温胁迫下的花粉育性QTL定位

 以耐热水稻品系996和热敏感品系4628为亲本构建的重组自交系为材料,采用水稻开花期高温胁迫下的花粉育性为指标,对水稻耐热性进行了QTL分析。采用复合区间作图法检测到2个花粉育性耐热性QTL,暂命名为qPF4和qPF6。qPF4位于第4染色体上的RM5687―RM471区间,LOD值为7.54,对高温胁迫下花粉育性的表型解释率为15.1%,来自耐热亲本996的等位基因使高温下花粉可育率提高7.15%。qPF6位于第6染色体上的RM190―RM225标记区间,LOD值为4.43,对高温胁迫下花粉育性的表型解释率为9.31%,能使高温下花粉可育率提高5.25%,加性效应亦来自耐热亲本996的等位基因。定位到的2个耐热QTL为进一步精细定位以及通过分子标记辅助选择培育耐热水稻新品种奠定了基础。     

THE EFFECTS OF LONG-TERM STORAGE ON THE VIABILITY OF S23 PERENNIAL RYEGRASS SEED AND ON SUBSEQUENT PLANT DEVELOPMENT

Eight lots of seed of S23 perennial ryegrass which had been artificially dried to different moisture levels and stored for 20 years were tested for germinating capacity, and the effects of long-term storage on subsequent plant development were studied. The results of the germination tests indicated a continuation of the downward trend in viability previously reported. Observations on the derived mature plants revealed no difference between lots in general growth habit; a few seedlings showed symptoms of some retardation in growth but most plants manifested the high tillering and prostrate growth typical of S23 perennial ryegrass. Pollen fertility was markedly reduced in 38% of all the plants sampled. The seed-setting capacity was affected to an even greater extent, 44% of the plants giving seed-set values decidedly below those obtained for plants grown from new seed. Where pollen fertility had been much reduced, seed-setting also was usually low, but there were some instances of satisfactory pollen fertility associated with a low seed set.     

温度对亚种间杂种花粉育性的影响

以17个不同类型的籼、粳、爪哇型品种及其杂种为材料,通过分期播种,研究了温度变化对花粉育性的影响。结果表明,当花粉母细胞减数分裂期的日平均气温低于22~23℃时,亚种间杂种的花粉育性显著降低,不同组合花粉育性存在明显差异,而品种间杂种和常规品种的花粉育性受影响较小;当花粉母细胞减数分裂期的日平均气温低于20℃时,常规品种和品种间杂种的花粉发育也受到不同程度的影响,不同品种与组合间存在差异。花粉母细胞减数分裂期的日平均温度与花粉育性的相关性分析表明,温度与花粉育性呈显著正相关,亚种间杂种与常规品种的相关系数存在极显著差异。说明减数分裂期的花粉育性受温度影响,温度对亚种间杂种花粉育性的影响较常规品种大。关键词     

Low Temperature Emergence in Crop Plants

Summary

In Canada, seeding of agronomically important crops takes place during the early months of spring when temperatures are well below the optimum. Low temperature reduces the rate and success of germination. This in turn can result in slow asynchronous emergence from the soil and poor stand establishment. As emergence is a function of both germination and early seedling growth, the effect of low temperature on these developmental processes is of great interest. This review examines how low temperature affects germination and early seedling growth in relation to biochemical and molecular processes. As Brassica napus L. cv. Westar, canola, does not exhibit primary or secondary dormancy, it serves as an ideal species in which to study low temperature emergence. First, emergence is reviewed by independent sections covering germination and early seedling growth. Germination is dissected into the three phases of germination. Early seedling growth is broken into sections covering storage reserve mobilization, the expression of gene sets related to developmental stages, and the role of ABA. Next, comparisons between chilling injury in seeds and chilling injury in plants, oxidative stress, and seed priming are discussed. Finally, the current state of experimental evidence and results are used to resynthesize low temperature emergence in Brassica napus with final thoughts on future directions.     

海南油茶不育株花器发育生物学特性及解剖学观察

从解剖学、细胞生物学及遗传学角度对海南油茶不育株花器发育过程导致不育的原因进行研究。以海南油茶正常株和不育株为实验材料,对其花芽发育过程外部形态特性进行阶段性比较观察,并应用花粉原位萌发技术检测其花粉萌发及花粉管发育差异;应用石蜡切片法对花芽分化过程中雌雄蕊进行解剖学观察,分析雌雄蕊发育时期与其花芽外部形态的相关性。结果表明：不育花与正常花外部形态上并无明显差异,但不育株开花后子房即脱落,表明没有正常授精,不育株柱头授粉后花粉粒不萌发,花粉管并不伸长;从雌雄蕊石蜡切片可以看出,不育株花器发育失常,其花药的绒毡层降解异常,无法形成成熟花粉粒,而在其胚珠发育过程中不育株未能形成成熟胚囊,导致空心胚珠。     

外源EBR对低温胁迫下火龙果苗抗氧化系统及脂肪酸不饱和度的影响

低温是限制火龙果生长发育和产量的重要因素。2,4-表油菜素内酯（2,4-epibrassinolide, EBR）能够增强植物对低温等多种逆境的抗性。为提高火龙果的耐寒性，缓解低温对其造成的伤害，以‘台湾6号’红心火龙果扦插苗为材料，外源喷施0.5 mg/L的EBR，在低温胁迫下（4℃/0℃，12 h/12 h）处理7 d，测定火龙果苗活性氧（ROS）含量、抗氧化酶活性、相对电导率（REC）、丙二醛（MDA）含量、脂肪酸组分及含量等，明确EBR对火龙果苗耐寒性的调控作用，进一步研究低温胁迫下抗氧化系统与膜脂脂肪酸不饱和度之间的关系，阐明EBR的作用机理。结果表明：（1）低温胁迫使火龙果苗ROS含量增加，不饱和脂肪酸含量显著下降，脂肪酸不饱和度（UFA/SFA）和双键指数（DBI）分别降低了32.1%和32.4%，导致膜稳定性降低，膜透性增大，MDA含量及REC显著升高，植株出现明显的水渍状斑点与轻微萎焉，寒害指数达0.60。（2）低温下，外源EBR处理提高了火龙果苗超氧化物歧化酶、过氧化物酶、过氧化氢酶活性，有效清除了过量积累的ROS，超氧阴离子产生速率、过氧化氢含量显著降低，从而缓解...     

橡胶树低温伤害的生理反应

在人工零上低温下,巴西橡胶树(Hevea brasiliensis)叶质膜透性随低温处理时间的延长而持续上升,抗冷品系的上升速率比不抗冷品系慢。呼吸强度和ATP含量均随处理时间的延长而持续下降,抗冷品系下降速率比不抗冷品系慢。叶绿体Mg~(++)—ATPase活性也表现出明显抗性差异。可见,低温下叶组织的质膜透性、呼吸强度、ATP含量以及Mg~(++)—ATPase活性的变化与品系抗冷性有关。低温下呼吸强度、ATP含量与质膜透性变化呈负相关,质膜透性的变化与供能有关。     

Effect of Temperature on Pollen Fertility in Inter-Subspecific Rice Hybrids

Seventeen rice varieties and hybrids of different types (indica, japonica, javanica, indica hybrid, japonica hybrid and inter-subspecific hybrid) were evaluated to determine the effect of temperature on pollen fertility in inter-subspecfic hybrids. The pollen fertility of inter-subspecific hybrids was greatly reduced when average daily temperature dropped to 22.0 - 23.0℃at meiosis stage, and the extent of pollen fertility reduction varied greatly with respect to different hybrids. However, the pollen fertility reduction of indica and japonica hybrids and conventional varieties was not obvious under the same regime of temperature conditions. When the average daily temperature dropped to 20℃, the pollen development of conventional varieties and hybrids was also affected. Correlation analysis revealed that there existed a positive correlation between pollen fertility and average daily temperature. A significant difference (P<0.01) was also found between the two correlation coefficients i.e. inter-subspecific hybrids and conventional varieties. Temperature at meiosis stage of pollen mother cell was a key factor in pollen developing, and the pollen fertility of inter-subspecific hybrids was more sensitive to low temperature than that of traditional variety.     

橡胶树细胞器的冷害

采用电子显微镜技术和酶的细胞化学法研究橡胶树(Hevea brasinensis)冷害细胞器结构的变化。实验结果表明,在零上低温下各种细胞器都遭到不同程度的损害,其中质膜是各种细胞器中对冷害最敏感的部位。叶绿体被膜比片层对低温更敏感,而线粒体内脊膜比外膜对低温更敏感。细胞器膜系的损害有三种形式:(1)双分子膜解体;(2)生物膜发生液化作用;(3)双分子膜撕裂。膜各种形式的伤害原因可能不同。     

马铃薯花蕾大小与花粉发育关系的研究

试验采用3个马铃薯栽培品种为材料,取2～12mm的花蕾,用醋酸—洋红压片法制片,在普通研究显微镜下观察花粉发育状况。试验结果表明,3mm以下的花蕾,花粉发育基本处在二分孢子和四分孢子时期,花蕾4～5mm大小时为花粉发育的单核高峰期,开花授粉前,大部分花粉为双核花粉,三核花粉的比例很小。处在发育早期的花粉均属正常,随着花粉发育进入到二核期以后,花粉畸形比例显著增加。品种间畸形花粉率存在显著差异。     

黑肩绿盲蝽在寄主植物、飞虱和叶蝉卵上的生长和发育

 系统地测定了不同寄主卵和寄主植物对稻飞虱重要天敌黑肩绿盲蝽Cyrtorhinus lividipennis Reuter生长和发育的影响。结果表明，在实验室条件下黑肩绿盲蝽能在水稻以及禾本科杂草如稗草Echinochloa glabrescens、千金子Leptochloa chinensis、马唐Digitaria ciliaris和狗牙根Cynodon dactylon上生长和繁殖。大田连续采样证实该盲蝽在稻田周围杂草地只能作短暂停留。黑肩绿盲蝽的若虫龄数随寄主卵和寄主植物的变化而变化，表现为5龄、6龄和4龄。水稻和禾本科花穗与飞虱蜜露或蜂蜜的结合可为黑肩绿盲蝽的生长和发育提供重要的营养源。该研究将为黑肩绿盲蝽的自然保护利用提供重要的理论依据。     

黑肩绿盲蝽在寄生植物、飞虱和叶蝉卵上的生长和发育

系统地测定了不同寄主卵和寄主植物对稻飞虱重要天敌黑肩绿盲蝽ＣｙｒｔｏｒｈｉｎｕｓｌｉｖｉｄｉｐｅｎｎｉｓＲｅｕｔｅｒ生长和发育的影响。结果表明，在实验室条件下黑肩绿盲蝽能在水稻以及禾本科杂草如稗草Ｅｃｈｉｎｏｃｈｌｏａｇｌａｂｒｅｓｃｅｎｓ、千金子Ｌｅｐｔｏｃｈｌｏａｃｈｉｎｅｎｓｉｓ、马唐Ｄｉｇｉｔａｒｉａｃｉｌｉａｒｉｓ和狗牙根Ｃｙｎｏｄｏｎｄａｃｔｙｌｏｎ上生长和繁殖。大田连续采样证实该盲蝽在稻田周围杂草地只能作短暂停留。黑肩绿盲蝽的若虫龄数随寄主卵和寄主植物的变化而变化，表现为５龄、６龄和４龄。水稻和禾本科花穗与飞虱蜜露或蜂蜜的结合可为黑肩绿盲蝽的生长和发育提供重要的营养源。该研究将为黑肩绿盲蝽的自然保护利用提供重要的理论依据。     

Genetic variation in the sensitivity of anther dehiscence to drought stress in rice

Field-based screens for genetic variation in reproductive-stage drought tolerance are often confounded by genetic variation in root depth, flowering date and biomass at flowering. To reduce these confounding effects and to impose drought stress more precisely, we grew contrasting genotypes of rice (Oryza sativa L.) in shallow containers of flooded soil. When water was withheld from the shallow-rooted indica genotype IR64 for 6 days starting at −17, −7, 0, 10 and 20 days after heading (DAH), the impact on grain yield was greatest at −7 and 0DAH. The most sensitive yield component was filled grain percentage (spikelet fertility). Data on yield and spikelet fertility were also obtained for another shallow-rooted lowland indica (BRRI Dhan 31) and two deep-rooted upland tropical japonicas (Azucena and Moroberekan). Compared with well-watered controls, withholding of water for 6 days reduced spikelet fertility by ∼80% in IR64, BRRI Dhan 31 and Azucena but by 22% in Moroberekan. In a detailed comparison, water was withheld from IR64 for 5 days and from Moroberekan for 6 days, starting 3 days before the heading date of well-watered controls. Under these stress conditions, heading was delayed for 4 days in IR64 and 6 days in Moroberekan. Spikelet fertility in the top four rachis branches was reduced by 80% in IR64 and 16% in Moroberekan, a difference attributable principally to reduced anther dehiscence and lower stigma pollen density in IR64. Two properties of Moroberekan may contribute to high anther dehiscence after stress/re-watering: (i) constitutively superior development of fibrous structures in the endothecium at the anther apex and base and (ii) better maintenance of pollen size. All ovaries of Moroberekan received pollen—an average of 60 grains in well-watered plants and 42 grains in stressed/re-watered plants. In well-watered IR64, all ovaries received an average of 31 grains, whereas in stressed/re-watered IR64, 67% of ovaries received no pollen and the remainder received an average of eight grains. Moroberekan may, therefore, be a source of reproductive-stage drought tolerance through genes that maintain anther dehiscence during recovery from low water status.     

玉米抗寒基因的克隆与表达研究

用DDRT-PCR技术研究玉米自交系承18在常温和不同低温处理下基因表达的变化,分离了10条差异表达的cDNA。序列分析结果表明:其中部分与前人克隆的抗逆cDNA同源,部分与信号传导相关基因同源,部分与功能未知的cDNA同源。用Northern杂交方法对差异片段MCI16做了进一步鉴定,同时还对玉米Cat3、拟南芥CBF1和FAD3基因在不同低温处理的玉米幼苗中的表达特性进行了研究,结果表明:MCI16、Cat3等基因受低温的诱导表达,对提高玉米的抗寒力起积极作用。     

低温对粳稻光温敏核不育系育性影响研究

籍2004年盛夏难得的14-16℃低温条件,对两系杂交水稻不育系在自然低温下的育性进行跟踪研究结果表明,低温能导致花粉不育度的明显降低,而且14-16℃的低温,不仅能使花粉不育度降低,而且还能诱导一定程度的自交结实;育性温度敏感期为幼穗分化第四期(雌雄蕊形成期至花粉母细胞形成期);在相同低温的条件下,短日处理的光温敏核不育系的不育度大大降低。对低温不敏感的不育系 G103,在短光作用下败育也较彻底。对短光不敏感的不育系是理想的不育系。不同株系间在低温下育性表达存在显著差异,且在自然短日低温务件下,这种差异更加明显。