Effects of Increased Supply of Potassium on Growth and Nutrient Content in Pearl Millet under Water Stress

Influence of increased K supply on growth and nutrient content in pearl millet (Pennisetum glaucum) under severe water stress was assessed in a pot experiment under glasshouse conditions. Nineteen-day-old plants of two lines, ICMV94133 and WCA-78 were subjected for 30 d to 235, 352.5, and 470 mg(K) kg^–1(soil) and two water regimes (100 and 30% field capacity). Increasing soil K supply did not alleviate the adverse effect of water deficit on the growth of two lines of pearl millet. Accumulation of N and K in the shoots of both lines was higher under water deficit than that under well-watered conditions, but such effect was not observed for P or Ca.     

S-Nitrosoglutathion Reductase Activity Modulates the Thermotolerance of Seeds Germination by Controlling ABI5 Stability under High Temperature

Seed germination or dormancy status is strictly controlled by endogenous phytohormone and exogenous environment signals. Abscisic acid (ABA) is the important phytohormone to suppress seed germination. Ambient high temperature (HT) also suppressed seed germination, or called as secondary seed dormancy, through upregulating ABI5, the essential component of ABA signal pathway. Previous result shows that appropriate nitric oxide (NO) breaks seed dormancy through triggering S-nitrosoglutathion reductase (GSNOR1)-dependent S-nitrosylation modification of ABI5 protein, subsequently inducing the degradation of ABI5. Here we found that HT induced the degradation of GSNOR1 protein and reduced its activity, thus accumulated more reactive nitrogen species (RNS) to damage seeds viability. Furthermore, HT increased the S-nitrosylation modification of GSNOR1 protein, and triggered the degradation of GSNOR1, therefore stabilizing ABI5 to suppress seed germination. Consistently, the ABI5 protein abundance was lower in the transgenic line overexpressing GSNOR1, but higher in the gsnor mutant after HT stress. Genetic analysis showed that GSNOR1 affected seeds germination through ABI5 under HT. Taken together, our data reveals a new mechanism by which HT triggers the degradation of GSNOR1, and thus stabilizing ABI5 to suppress seed germination, such mechanism provides the possibility to enhance seed germination tolerance to HT through genetic modification of GNSOR1.     

烤烟不同生育时期产量性状的遗传效应分析

以烤烟高产品种竖把老母鸡和台烟7号与低产品种TI245配制成2个杂交组合,分别获得6个世代植株(P1、P2、F1、F2、B1、B2),运用主基因+多基因混合遗传多世代联合法对2个组合不同生育时期的产量性状进行遗传分析。研究结果表明,2个组合的产量性状在性状建成中发挥调控作用的基因数目与基因效应存在发育阶段性差异。基因加性效应与显性效应存在于整个发育过程中,且效应程度在不同生育时期存在明显差异,同时加性×加性、显性×显性互作效应在产量性状的发育过程中呈间断性表达。基因遗传力在不同生育时期存在差异,现蕾期产量性状的表型变异受基因遗传效应的决定作用高于其他2个生育时期,受环境因素影响小,且不同组合间的基因效应也存在显著差异,组合Ⅱ的遗传效应明显高于组合Ⅰ。不同组合的烤烟产量性状在不同生育时期主基因+多基因遗传效应差异显著,受环境影响程度不同,因此在育种工作中既要考虑基因效应,又要注意环境影响。     

桃儿七种子解剖结构及其萌发生长期形态特征

为探明种皮和胚乳是否是限制桃儿七种子萌发的主要因素,利用组织切片和显微技术,对桃儿七种子及其不同萌发期（1、7、14、21、28 d）解剖结构和播种后一定时期内（7~210 d）的植株生长形态进行观察。桃儿七种子由种皮、胚乳和胚构成。种皮包括外种皮和内种皮,外种皮致密规整,由外至内分别为栅状石细胞和表皮层细胞,内种皮由5~6层海绵细胞组成。胚乳占种子体积的绝大部分,包括珠孔胚乳和外胚乳。胚由胚根、胚轴和子叶组成,被致密种皮、多层珠孔胚乳和外胚乳包围。萌发期1~7 d胚根和胚轴开始伸长,7~14 d两片子叶分离,14~21 d胚根突破珠孔胚乳和种皮,21~28 d胚根、胚轴和子叶继续扩张伸长。种子播种210 d后可平均形成3片功能真叶和5条不定根。致密种皮（物理休眠）和多层胚乳（机械休眠）是限制桃儿七种子萌发的两个主要因素。     

Lead (Pb)-Induced Regulation of Growth, Photosynthesis, and Mineral Nutrition in Maize (Zea mays L.) Plants at Early Growth Stages

The phytotoxic effects of lead (Pb) on seed germinability, seedling growth, photosynthetic performance, and nutrient accumulation (K(+) and Cu(2+)) in two maize genotypes (EV-1098 and EV-77) treated with varying levels of PbSO(4) (0.01, 0.1, and 1.0 mg L(-1)) were appraised in this study. In the seed germination experiment, lead stress significantly reduced seed germination percentage and index, plumule and radicle lengths as well as fresh and dry weights in both genotypes. In the second experiment, lengths and fresh and dry weights of shoots and roots decreased due to Pb in both genotypes with increase in plant age. Higher Pb levels also decreased photosynthetic rate (A), water use efficiency (A/E), and intrinsic water use efficiency (A/g(s)), but increased transpiration rate (E) and C(i)/C(a) ratio as a result of increase in stomatal conductance (g(s)). The concentrations of K(+) and Cu(2+) decreased in root, stem, and leaves of both genotypes, which could be a direct consequence of multifold increase in Pb concentration in these tissues. Overall, cv. EV-1098 had better Pb tolerance potential than EV-77 because the former genotype showed less reduction in seed germinability parameters, photosynthetic performance, and K(+) and Cu(2+) accumulation in shoot and root under lead stress.     

Effects of Fusicoccin on the Early Stages of Sorghum Growth at High NaCl Concentrations

The effects of fusicoccin (FC) on the early growth processes in sorghum (Sorghum vulgare M.) seeds germinated in water and in 0.1 M or 0.2 M NaCl solutions were investigated. We studied the rate of seed imbibition, the onset of radicle protrusion, the occurrence of the first mitoses, the mitotic index, the distribution of cells according to the phases of the cell cycle, as well as the length and weight of roots. Seed imbibition was considerably accelerated by treating them with 5 × 10^–6 M FC for 1 h. In these FC-treated seeds placed on NaCl solutions, FC stimulated water influx into seeds, radicle protrusion, and occurrence of the first mitoses. FC pretreatment did not affect substantially the distribution of meristematic cells according to the periods of the cell cycle after 72 h of seed germination on water or 0.1 M NaCl. Root growth was inhibited by 0.1 M NaCl, but it was partially recovered in the presence of FC. 0.2 M NaCl caused a decrease in the mitotic index and in the number of cells in the S phase, an accumulation of cells in the G₂ period and in the prophase, as well as a considerable inhibition of root growth. FC pretreatment of seeds subsequently germinated on 0.2 M NaCl resulted in an increase in the number of cells in the G₁ period, in the mitotic index, and in the root-growth rate. FC virtually did not affect the growth of sorghum in the absence of salt. Pretreatment of seeds with FC followed by salinization resulted in an increase in the water content in seeds. It is suggested that a FC-induced increase in the water content of seeds accelerated metabolic processes in seeds germinating on NaCl solutions, thus regulating ionic homeostasis and thereby stimulating the initial growth processes.__________Translated from Fiziologiya Rastenii, Vol. 52, No. 3, 2005, pp. 378–383.Original Russian Text Copyright © 2005 by Lutsenko, Marushko, Kononenko, Leonova.     

Nutrient acquisition and limitation for the photoautotrophic growth of Synechocystis sp. PCC6803 as a renewable biomass source

Photoautotrophic microorganisms (cyanobacteria and algae) offer high promise as a source of biomass for renewable energy due to their rapid growth rates and high biomass yields. To provide a framework for evaluating the feasibility of growing phototrophic microorganisms with high biomass production rates, we operated a bench‐scale photobioreactor using Synechocystis sp. PCC6803 and with light conditions imitating actual day–night light irradiance (LI). During the time of peak LI, PCC6803's specific growth rate (1.7 day⁻¹) and the nitrate uptake rate (0.46 g N/g DW day) were high compared to past reports. Analysis employing the stoichiometry of photosynthesis of PCC6803 and ionic speciation showed that bicarbonate and phosphate were driven to very low concentrations for the high‐LI conditions. In particular, the systematic evaluation of rate‐limiting factors identified when the CO₂–C_i supply rate needed to be increased to mitigate HCO depletion and a large pH increase. It also showed that the traditional BG‐11 medium needs to be augmented with phosphate to avoid severe P depletion. This work exploits quantitative understanding the stoichiometry and kinetics of cyanobacteria for the high‐rate production of a renewable biomass. Biotechnol. Bioeng. 2011;108: 277–285. © 2010 Wiley Periodicals, Inc.     

不同生长阶段苘麻生物量分配对种群密度和土壤水分的响应

通过研究不同生长阶段下植物生物量分配对土壤水分和种群密度的响应,揭示植物同时应对生物与非生物环境因子的策略。本研究在田间条件下对1年生草本植物苘麻（Abutilon theophrasti）进行加水和对照2种水分处理,每种处理下进行低、中、高3种种植密度处理,分别在生长20、50 d时测量植物根、茎、叶片、叶柄和繁殖（花和果实）生物量,探讨在不同生长阶段苘麻生物量分配如何响应于密度和水分。结果表明：植物生长20 d时,在加水处理中,与低密度相比,中密度提高了根生物量比率19.4%和根冠比21.5%,降低了叶生物量比率34.4%;未加水处理（对照）中生物量分配对密度的响应不显著;50 d时,对照处理下,高密度相对于低密度降低了总生物量63.5%,2种水分处理下高密度都降低了根冠比和根生物量比率,提高了茎生物量比率,不影响总生物量和其他器官生物量分配。结果说明施加水分前期更容易促进根生物量分配对密度的积极响应（增大）,后期减缓高密度对总生物量的不利影响（降低）。生物量分配对密度的响应取决于种内相互作用的强度,早期适中水平的相互作用更容易产生地下促进作用,促进根部的积极响应。中密度下适中的种...     

Induction of Heat Shock Proteins and Acquisition of Thermotolerance in Germinating Pigeonpea Seeds

Heat shock proteins (HSPs) ranging in molecular masses from 14 to 110 kDa were induced in embryonic axes of germinating Cajanus cajan (L.) Millspaugh seeds after exposure to 40 °C for 1 or 2 h. At 45 °C, there was a marked decline in synthesis of HSPs. A close relationship was observed between HSPs induced and the growth of the germinating seeds. Pretreatment of germinating seeds at 40 °C for 1 h or 45 °C for 10 min followed by incubation at 28 °C for 3 h led to considerable thermotolerance (45 °C, 2 h) and the recovery of protein synthesis. This revised version was published online in July 2006 with corrections to the Cover Date.     

Frequency and Biodiversity of 2,4-Diacetylphloroglucinol-Producing Bacteria Isolated from the Maize Rhizosphere at Different Stages of Plant Growth

A Pseudomonas 2,4-diacetylphloroglucinol (DAPG)-producing population that occurred naturally on the roots, in rhizosphere soil of Zea mays and in the nonrhizosphere soil was investigated in order to assess the microbial diversity at five stages of plant growth. A total of 1,716 isolates were obtained, and 188 of these isolates were able to produce DAPG. DAPG producers were isolated at each stage of plant growth, indicating that the maize rhizosphere is colonized by natural DAPG producers throughout development. The frequency of DAPG producers was very low in the first stage of plant growth and increased over time. An analysis of the level of biodiversity of the DAPG producers at the species level was performed by comparing the AluI restriction patterns of the 16S ribosomal DNAs (rDNAs) amplified by PCR from 167 isolates. This comparison allowed us to cluster the isolates into four amplified rDNA restriction analysis (ARDRA) groups, and the main group (ARDRA group 1) contained 89.8% of the isolates. The diversity of the 150 isolates belonging to ARDRA group 1 was analyzed by the random amplified polymorphic DNA (RAPD) technique. An analysis of RAPD patterns by a molecular variance method revealed that there was a high level of genetic diversity in this population and that the genetic diversity was related to plant age. Finally, we found that some of the DAPG producers, which originated from all stages of plant growth, had the same genotype. These DAPG producers could be exploited in future screening programs for biocontrol agents.     

水稻胚胎发生与萌发早期分离胚中内源激素的变化

以酶联免疫吸附检测技术分析了水稻(Oryza sativa ssp. japonica)分离胚不同发育时期及萌发早期的内源激素含量的动态变化.GA1含量是所测激素中含量最高的.GA1的变化趋势基本上与ABA相反.花后4 d的胚中GA1和ABA的含量最高;花后8 d到18 d,GA1的含量下降,而ABA含量增加.在早期萌发过程中,种子吸涨后2 d的胚中GA1含量迅速上升,而ABA下降.GA1/ABA的最高比值也出现在吸涨后2 d的胚中.iPAs和ZRs的最高含量也出现在开花后4 d的胚中,但随后含量均下降到相当低的水平,并几乎没有变化.研究结果进一步证实了GA1在早期胚胎发生和萌发过程中起重要的作用;推测iPAs和ZRs可能仅在胚胎发生的早期起作用;GA1与ABA含量之间的相对平衡控制着胚胎发育的过程.用分离胚作为测试材料可以避免胚乳等其他组织成分的干扰,从而比较准确地反映了胚的内源激素变化.此外,本研究是首次用4 d的水稻幼胚作为激素含量测定的起始材料.     

宁夏赤霞珠葡萄不同发育期晚霜冻害阈值试验研究

【目的】葡萄霜冻温度阈值是葡萄霜冻监测、预测、评估与防御的基础。对贺兰山东麓主栽酿酒葡萄‘赤霞珠’不同发育期低温忍耐力进行研究分析,建立葡萄霜冻温度阈值体系,旨为贺兰山东麓地区酿酒葡萄霜冻预测、防御提供理论依据。【方法】于2022年4—5月采用野外霜冻试验箱原位试验方法对贺兰山东麓主栽酿酒葡萄品种‘赤霞珠’不同发育期绒球、芽、新叶、新梢进行低温处理,测定其过冷却点、相对电导率（REC）及半致死温度（LT50）,同时对低温胁迫后的受冻指数进行田间跟踪调查,利用受冻率与低温建立关系模型,计算不同发育期轻、中、重度受冻温度阈值。对不同发育期过冷却点、半致死温度（LT50）及霜冻指标温度阈值进行综合分析,确定不同发育期霜冻温度阈值。【结果】结果表明：不同低温对‘赤霞珠’绒球期、芽开放期、展叶期和新梢生长期的影响程度不同,温度越低,各发育期的受冻率越大;随发育进程推进,‘赤霞珠’过冷却点温度、半致死温度逐渐升高;绒球期的低温耐受性最强,芽开放期、展叶期次之,新梢生长期最弱。【结论】研究认为：-7.70℃是绒球期重度受冻的起始温度;芽开放期遭受重度霜冻的临界温度为-4.49℃;展叶期在-2.79℃即遭受不可逆伤害;新梢生长期出现低于-1.62℃以下的低温,会造成严重的霜冻。     

菊花不同生长阶段不同器官POD和EST同工酶比较

采用过氧化物酶(POD)、酯酶(EST)2个酶系统的12个同工酶位点,分析了4个菊花品种营养生长和生殖生长阶段不同器官(嫩叶、老叶、嫩茎、木质化茎)的同工酶变化.结果表明:(1)4个品种共有16种POD酶带,15种EST酶带;(2)菊花的POD和EST具有组织特异性和阶段特异性,其中以嫩叶的酶带最多,其次为老叶,再次为嫩茎,而木质化茎的酶带最少;(3)与生殖生长阶段相比,营养生长阶段的POD酶带更清晰,更整齐,分离更好,但生殖生长阶段的EST同工酶比营养生长阶段的更清晰;(4)营养生长阶段的嫩叶最适合用于菊花POD同工酶分析,而EST同工酶研究宜取生殖生长时期的嫩叶.     

水稻胚胎发生与萌发早期分离胚中内源激素的变化

以酶联免疫吸附检测技术分析了水稻(Oryza sativa ssp．iapoica)分离胚不同发育时期及萌发早期的内源激素含量的动态变化。GA1含量是所测激素中含量最高的。GA1的变化趋势基本上与ABA相反。花后4d的胚中GAl和ABA的含量最高;花后8d到18d,GA1的含量下降,而ABA含量增加。在早期萌发过程中,种子吸涨后2d的胚中GA,含量迅速上升,而ABA下降。GA1／ABA的最高比值也出现在吸涨后2d的胚中。iPAs和ZRs的最高含量也出现在开花后4d的胚中,但随后含量均下降到相当低的水平,并几乎没有变化。研究结果进一步证实了GAl在早期胚胎发生和萌发过程中起重要的作用;推测iPAs和ZRs可能仅在胚胎发生的早期起作用;GA1与ABA含量之间的相对平衡控制着胚胎发育的过程。用分离胚作为测试材料可以避免胚乳等其他组织成分的干扰,从而比较准确地反映了胚的内源激素变化。此外,本研究是首次用4d的水稻幼胚作为激素含量测定的起始材料。     

外源水杨酸预处理对高温胁迫下白菜耐热性和光合特性的影响

采用叶片喷施水杨酸（SA）的方法,研究高温胁迫下外源SA预处理对‘夏帝’和‘苏州青’2个白菜品种耐热性和光合特性的影响。结果表明：SA预处理降低了高温胁迫下白菜叶片的电解质渗透率、MDA和脯氨酸含量以及净光合速率（R）,从而缓解高温对质膜的过氧化伤害,并且通过提高可溶性糖和可溶性蛋白含量、SOD和POD活性来适应高温环境;然而SA预处理对气孔导度（GS）和蒸腾速率（功的影响在2个品种中变化相反,而对胞间CO2浓度（G）的影响差异不大。与耐热性较强的白菜品种‘夏帝’相比,耐热性较弱的品种‘苏州青’经SA预处理对缓解高温胁迫的影响效果更为明显。     

Diel variation in surface and subsurface microbial activity along a gradient of drying in an Australian sand-bed stream

1. Microbes play key roles in nutrient transformation and organic matter mineralisation in the hyporheic zone but their short‐term responses to diel variations in discharge and temperature are unknown. Rates of microbial esterase activity were hypothesised to vary vertically and along a gradient of moisture in a drying sand‐bed stream where discharge fluctuated daily in response to evapotranspiration. 2. At ‘fully saturated’, ‘moist’ and ‘dry’ locations in three sites along a drying Australian sand‐bed stream, microbial activity at three depths (surface, 10 and 30 cm) was assessed using fluorescein diacetate hydrolysis. Samples were collected in mid‐summer in the late afternoon and again at dawn to assess diel variation in hydrolytic activity at each site and depth. Data loggers tracked diel variations in temperature at each depth. 3. Hydrolytic activity was up to 10‐fold greater in the surface sediments in late afternoon than at dawn in all habitats, and was correlated with surface sediment temperature. Diel differences in activity were not detected at 10 cm, although daily thermal cycles were evident at this depth. Unexpectedly, activity was marginally higher at dawn at 30 cm in all habitats, perhaps reflecting lags in temperature at that depth. 4. Overall, microbial activity declined with depth, strongly correlated with vertical trends in total organic matter and concentrations of dissolved phosphorus. Particulate organic matter, probably buried during a flood 35 days earlier, appeared largely responsible for these vertical trends. On the other hand, there was little evidence for hydrological exchange between much of the hyporheic zone and the surface stream, implying that processes in the subsurface zone of this stream are effectively isolated during baseflow in mid‐summer. 5. Diel cycles of wetting and drying in the moist habitats did not enhance esterase activity relative to the dry or fully saturated habitats. Sediment moisture was not correlated with microbial activity, and mats of senescent algae appeared to inhibit water loss from surface sediments in the moist habitat. In this sand‐bed stream, local diel fluctuations in water level appear to have less influence on microbial activity and mineralisation of organic matter in the sediments than occasional floods that bury leaf litter and renew many hyporheic zone functions. Subreach‐scale processes seem to be the major driving force of microbial processes and nutrient cycling in this sand‐bed river.     

激光诱变小麦生育期性状和穗部性状的生物学效应研究

本试验采用N2激光和He—Ne激光辐照“绵阳21号”等四个小麦材料的干种子,采用随机区组设计,重复三次,利用生物统计和数量遗传学的方法,对L。和L：两代的抽穗期、开花期等4个生育期性状及穗长、小穗粒数等10个穗部性状的遗传变异进行研究。结果表明：辐射材料不同,诱变后代的变异差异明显;激光种类不同,后代变异差异不大;抽穗期穗长、小穗粒数的遗传力较高,早代单株选择的效果较好。     

Introduction of Human Recombinant Angiogenin at the Early Stages of Postnatal Development Inhibits the Growth of Mice

We studied the influence of recombinant DNA containing the cloned angiogenin gene, plasmid DNA without angiogenin gene, and purified recombinant angiogenin injected to Tg8 mice at the age of two days on the body mass of 28- and 40-day old mice. The body mass of mice that were injected with the cloned angiogenin gene or purified angiogenin was less than in the control mice. The body mice of Tg8 mice injected with recombinant DNA containing the cloned angiogenin gene did not increase from day 28 to day 40, while in the mice with purified recombinant angiogenin and control mice it increased by 24 and 57%, respectively. These data suggest that the elevated level of angiogenin at the early developmental stages inhibits the increase of body mass. The effect we described is related, in al likelihood, to the known inhibitory effect of angiogenin on protein synthesis.     

荚蒾属植物花期物候及生长对引种地年际气候波动的响应

专属引种植物的物候及生长研究能够掌握特定物候相在专属水平上的阈值,并为评估引种专属的适应潜力提供参考。通过对中国科学院植物研究所北京植物园内引种多年的9种荚蒾（Viburnum）的花期及2种荚蒾的生长动态进行观测,分析讨论了花期对冬春两季异常低温的响应及营养与生殖生长的关联机制。结果表明：2009–2010年冬春异常低温后,荚蒾始花期的整体延迟是由春季环境热量供应不及时所致,种间延迟程度的差异则与原产地的气候有紧密联系：分布于寒温带地区的欧洲绣球（V.opulus）和修枝荚蒾（V.burejaeticum）延迟天数最少（分别为10和12天）,分布于我国亚热带的琼花（V.macrocephalum）和桦叶荚蒾（V.betulifolium）延迟天数最多（分别为21和26天）。荚蒾花前有效积温介于39–368°C之间。经历异常低温后,花前有效积温呈上升和下降两种格局,与物种冷量和热量的内在需求有关。荚蒾属植物的生殖与营养生长呈现两种关联方式,早花种类开花座果伴随着营养生长的竞争,晚花种类花后即出现营养生长的支持,对果实发育的保障性较强。