Dynamic QTL analysis for activity of antioxidant enzymes and malondialdehyde content in wheat seed during germination

Antioxidant enzymes played an important role in seed germination. In this study, Quantitative trait locus (QTLs) for activity of antioxidant enzymes (AEAs) and malondialdehyde (MDA) content in different time of seed germination were first identified, and antioxidant enzymes investigated included superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT). QTL analysis was conducted both in unconditional and conditional methods., which demonstrated the “static” and “dynamic” expression of QTLs controlling AEAs and MDA content during wheat germination, respectively. Twenty-two unconditional QTLs were detected on 1A, 1B, 1D, 2B, 2D, 3A, 4A, 6B, 7A, 7B, and the contributions ranged from 8 % of CAT3 to 28.46 % of MDA3. Fifteen conditional QTLs were detected on 1A, 1B, 1D, 2B, 2D, 4A, 5B, 6B, 7A, 7D, and the contributions ranged from 8.59 % of CAT5|3 to 30.18 % of MDA3|1.     

水淹胁迫对华南地区3种园林树种生理特征的影响

为了了解红荷、红苞木、樟树幼苗的抗涝能力,为筛选优良的抗涝树种提供依据,通过人工模拟水淹胁迫环境,测定这3种幼苗叶片的叶绿素等生理指标,用主成分分析法研究了这3种幼苗的抗涝性。研究结果表明：随着水淹胁迫时间的延长,红荷幼苗叶片叶绿素含量波动,红苞木和樟树小幅上升后下降;3种幼苗叶片的可溶性糖含量呈波动性上升的趋势;红苞木和樟树的蛋白质含量呈现波动性变化,红荷的蛋白质含量为降-升-降;红荷的叶片的超氧化物歧化酶(SOD)活性呈逐渐下降趋势,红苞木和樟树的SOD活性显著上升后下降;红荷、红苞木和樟树幼苗叶片的丙二醛(MDA)含量大幅增加后缓缓下降。3种幼苗在水淹28天期间内均有一定的抗涝性,采用主成分分析法得出幼苗的抗涝性大小为樟树>红荷>红苞木。     

Modelling wheat yield change under CO2 increase,heat and water stress in relation to plant available water capacity in eastern Australia

Increasing heat and water stress are important threats to wheat growth in rain-fed conditions. Using climate scenario-based projections from the Coupled Model Intercomparison Project phase 5 (CMIP5), we analysed changes in the probability of heat stress around wheat flowering and relative yield loss due to water stress at six locations in eastern Australia. As a consequence of warmer average temperatures, wheat flowering occurred earlier, but the probability of heat stress around flowering still increased by about 3.8%–6.2%. Simulated potential yield across six sites increased on average by about 2.5% regardless of the emission scenario. However, simulated water-limited yield tended to decline at wet and cool locations under future climate while increased at warm and dry locations. Soils with higher plant available water capacity (PAWC) showed a lower response of water-limited yield to rainfall changes except at very dry sites, which means soils with high PAWC were less affected by rainfall changes compared with soils with low PAWC. Our results also indicated that a drought stress index decreased with increasing PAWC and then stagnated at high PAWC. Under high emission scenario RCP8.5, drought stress was expected to decline or stay about the same due to elevated CO₂ compensation effect. Therefore, to maintain or increase yield potential in response to the projected climate change, increasing cultivar tolerance to heat stress and improving crop management to reduce impacts of water stress on lower plant available water holding soils should be a priority for the genetic improvement of wheat in eastern Australia.     

铅污染对土壤微生物及酶活性的影响

摘要：通过室内培养试验,研究了土壤铅污染对土壤微生物基础呼吸及土壤脲酶、脱氢酶、酸性磷酸酶的影响,结果表明,随着土壤铅添加浓度的提高,土壤微生物基础呼吸呈现出上升的趋势,土壤脲酶则随着铅浓度的增加呈现出不断下降趋势,土壤脱氢酶活性则在低浓度下上升而随着添加浓度的进一步提高迅速降低,可见,这两种酶对土壤铅毒害反应灵敏,可以作为土壤铅污染评价的指标,而土壤磷酸酶则对铅浓度的变化没有表现出明显的统计规律性,不适宜作为土壤铅污染评价的酶学指标。     

水分胁迫对花生幼苗叶片内源激素含量的影响

研究了水分胁迫对花生幼苗叶片内源激素含量的影响。结果表明,GA3含量先升后降,出现了两个高峰值,ABA含量则逐渐升高,IAA和ZR先降低后升高。随着胁迫时间的延长,叶片中ABA/IAA的值先升后降,ABA/ZR逐渐升高。     

The effect of potassium gibberellate and naphtaline acetamide on pod setting in intervarietal crosses of common bean,Phaseolus vulgaris L.

Summary The potential effects of two hormones, namely potassium gibberellate (P.G.) and naphtaline acetamide (N.A.), on pod setting in bean were investigated in three crossing programs, set up with five varieties of bean. Shortly after each crossing, a cut was made on the calyx and a mixture of lanoline + P.G. (2%) or of lanoline + P.G. (2%) + N.A. (1%) was applied. Lanoline alone was used as a control. When compared with the control, lanoline + P.G. (2%) increased the number of pods, although significantly so only in two of the programs. Lanoline + P.G. (2%) + N.A. (1%) increased the number of pods by 23.39 to 25.46%.     

The effect of in planta TIBA and proline treatment on somatic embryogenesis of sugar beet (Beta vulgaris L.)

The effect of in planta TIBA and L-proline onin vitro seedlings and cell culture of sugar beet was investigated. Sterilized seeds were grownin vitro on 1/2 MS medium supplemented with 0 or3 mg/l TIBA. Calli obtained on young leaves cultured on MS medium containing 1 mg/l BAP, were used for the initiation of cell suspension cultures using MS basal composition supplemented with 0 or 50 mM proline. Aliquots of 1 ml from cell suspension culture were inoculated onto the first somatic embryo induction MS medium containing TIBA 0.5 mg/l, BAP 1.0 mg/l, and proline at 0 or 50 mM. After three weeks of culture, embryogenic calli were transferred to the second embryo induction medium supplemented with NAA and BAP at 0.2 and 0.5 mg/l, respectively. The frequency of somatic embryos of calli obtained from in plantaTIBA together with proline treatments on average was20 which was higher than that of the other treatments. This revised version was published online in July 2006 with corrections to the Cover Date.     

Yield variation of spring cereals in relation to selected soil physical properties on three clay soil fields

The crop growth is highly dependent on growth conditions which vary from year to year making precision farming challenging. In the present paper was first investigated whether varying soil physical properties reflect the within-field yield variation of small grain cereals and how do the variations in weather conditions between growing seasons affect the within-field yield variation. Secondly, the potential biomass accumulation of the crop in existing soil and weather conditions was simulated. The simulated and experimentally based site-specific total biomasses were compared in order to find out whether the soil data explains the observed variations in yield.Three experimental fields size of 3–4 ha were established to examine the spatio-temporal yield variation during three years. The clay content of soils was high (> 46%) and soils were classified as Stagni-Vertic Cambisols. Correlations between soil water retention properties and crop yield were studied. Top and subsoil saturated (SWC), field capacity (FC) and permanent wilting point (PWP) water content, and saturated hydraulic conductivity of soil (K_sat), were determined from 19 to 24 places on each field once during the three years experimental period. During growing seasons, soil moisture content and leaf area index (LAI) were determined at same places biweekly, and yield was harvested. Spring barley (Hordeum vulgare) was grown on two fields, and spring wheat (Triticum aestivum, 2 years) and spring oilseed rape (Brassica napus L., one year) were grown on the third field.The measured grain yields correlated with selected soil physical properties only in few cases. The observed spatial variation in the biomass was in most cases found to be higher than the simulated. Therefore, the above mentioned parameters were not enough to predict the yield correctly in case of high variations. There were other factors decreasing the observed yield e.g. lodging, cold summer, extremely high precipitation and slopes in field. According to our results it is evident that it is very difficult to predict site-specific biomass accumulation solely by soil properties in order, for instance, to fertilize in a site-specific manner. Therefore one needs to measure the crop during the growing season in order to simulate the biomass accumulation for precision farming purposes.     

The inheritance of bean size,pod size and number of beans per pod in cocoa (Theobroma cacao L.), with a note on bean shape

Studies have been made on the F₁ and F₂ generations of crosses between the Amazon clones Nanay 32, Parinari 7, and Parinari 35. There is wide variation in size from pod to pod on a tree, and this is largely paralleled by variation in bean number, bean size remaining relatively constant. However in some trees bean size increases in the largest pods, bean number remaining constant. It appears that if a pod is too small for the inherent number of beans to be present at their inherent size, the number of beans which develop is reduced so that their inherent size is attained; if the pod is larger than is required for the full number of beans to attain their inherent size the beans may increase in size above the inherent value. Thus if the average bean size in a sample of pods taken from a tree indicates the inherent bean size reasonably accurately it is likely that the inherent bean number will be relatively underassessed, and conversely if the observed bean number indicates the inherent number relatively accurately it is likely that the observed bean size will overassess the inherent size. Scatter-diagrams may therefore be more informative than averages.Bean number and bean size are strongly inherited but the difficulties described above tend to obscure the pattern. In the Pa7 x Na32 F₁ progeny inherent bean sizes are low and probably relatively constant while inherent bean numbers vary widely; in consequence inherent bean numbers are well indicated by samples of pods taken from the trees, and inheritance of bean number in the F₂ progenies is very clear while inheritance of bean size is not. In contrast, in the F₁ of Pa35 x Na32, there is clear segregation in bean size while bean numbers are relatively high and constant; inheritance of bean size in the F₂ progenies is clear while the evidence of inheritance of bean number is weaker.The average pod weight of a progeny seems to be determined by the inherent bean size and the inherent bean number.Bean breadth and bean thickness tend to be negatively correlated. It is suggested that where the number of ranks of beans in a pod is high relative to the length of the pod and the inherent bean size, the beans, lacking room for expansion in thickness, tend to increase in breadth so as to attain the inherent size. Short fat pods may therefore tend to contain broad, thin, plate-like beans.     

Leaf thickness and response of leaf photosynthesis to water stress in soybean varieties

Summary A comparative study of photosynthetic response to soil moisture was conducted with soybean varieties (Harosoy, Norin No. 1 and Hogyoku). When the plants were grown in May before the rainy season under a high radiation level, per unit leaf area the photosynthetic rate of Harosoy leaves was significantly higher throughout the entire range of soil water potentials and leaf water potentials than that of Norin No. 1 leaves. The high photosynthetic rate of Harosoy under non-stress conditionsaand mild water stress was associated with both the high specific leaf weight and the high leaf areal nitrogen content. The photosynthetic response of the Harosoy leaves developed during rainy season under a low radiation level, however, was similar to that of Norin No. 1; no significant difference was observed between these two varieties in the specific leaf weight and in the leaf areal nitrogen content.On the other hand, Hogyoku cultivated especially along the footpaths between the paddy field was very sensitive to water stress, closing the stomata at higher soil water potentials. Under non-stress conditions, as compared with per unit leaf nitrogen content, however, Hogyoku performed higher leaf photosynthesis even with a thinner leaf than Harosoy.     

The effect of exogenous ethylene and methyl jasmonate on pal activity,phenolic profiles and antioxidant capacity of carrots (Daucus carota) under different wounding intensities

In this study it was shown that wounding in combination with hormone stresses synergistically enhanced the accumulation of bioactive phenolic compounds in carrot tissue. Whole carrots and carrots cut in slices, pie-cuts and shreds were exposed to 250 μL/L methyl jasmonate and 1000 μL/L ethylene treatments. Results indicated that hormone stress-induced phenolic compounds and phenylalanine ammonia lyase enzyme activity were dependent upon wounding intensity. The synthesized phenolics correlated to an increase in antioxidant capacity (AOX). In addition, both stresses affected the phenolic profiles. The different proportions of chlorogenic acid, dicaffeoylquinic acid and ferulic acid, for each stress and combinations, influenced the specific AOX of the phenolic profiles (the effectiveness of the phenolic compounds to neutralize free radicals). The bitter compound isocoumarin was mostly affected by the ethylene treatment compared to methyl jasmonate or wounding alone. Exposure to combined abiotic stresses could provide more AOX to regular diets and be a less expensive alternative to genetic modifications and breeding programs.     

Improving adaptation to drought stress in white pea bean (Phaseolus vulgaris L.): Genotypic effects on grain yield,yield components and pod harvest index

Common bean (Phaseolus vulgaris L.) is the most important food legume crop in Africa and Latin America where rainfall pattern is unpredictable. The objectives were to identify better yielding common bean lines with good canning quality under drought, and to identify traits that could be used as selection criteria for evaluating drought‐tolerant genotypes. In all, 35 advanced lines were developed through single seed descent and evaluated with a standard check under drought and irrigated conditions at two locations over 2 years in Ethiopia. Grain yield (GY), pod number per m², seed number per m² and seed weight decreased by 56%, 47%, 49% and 14%, respectively, under drought stress. Eight genotypes had better yield with good canning quality under drought compared to the check. Moderate to high proportion of genetic effects were observed under drought conditions for GY and yield components compared to genotype × environment effects. Significant positive correlations between GY and pod harvest index (PHI) in drought suggest that PHI could be used as an indirect selection criterion for common bean improvement.     

铜浸种对玉米幼苗生长和抗氧化酶的影响

利用不同浓度的CuSO4.5 H2O对玉米浸种,研究铜(Cu2+)对玉米幼苗生长和抗氧化酶的影响。结果表明:当Cu2+浓度小于10 mg/L时促进幼苗生长,高出这个浓度时则表现出抑制作用;当Cu2+浓度小于10 mg/L时,抗氧化酶SOD,POD和CAT活性及MDA含量下降,高出这个浓度时则相反;随着Cu2+浓度增大,叶片和根系吸收Cu2+逐渐增加。CuSO4.5 H2O胁迫对根的生长和抗氧化系统及Cu2+的积累比茎叶更为敏感。     

多酚含量及多酚氧化酶活性与柑橘胚性愈伤组织褐化的关系

研究测定了9种不同品种/基因型柑橘胚性愈伤组织的多酚含量和多酚氧化酶（polyphenol oxidase, PPO）的活性,对其与柑橘愈伤组织褐化的关系进行了探讨。结果表明,不同柑橘品种/基因型间多酚含量和PPO活性有明显不同;多酚含量高的宽皮柑橘类胚性愈伤组织容易褐化,葡萄柚与甜橙类的次之,说明柑橘胚性愈伤组织褐化与多酚含量成正相关;PPO活性与柑橘愈伤组织褐化无明显相关。     

低温胁迫对油棕幼苗光合作用及叶绿素荧光特性的影响

在30 μmol/(m2.s)的弱光条件下,以25℃、10℃、7℃、4℃、1℃各处理油棕幼苗3天,测定了油棕幼苗叶片光合参数及叶绿素荧光参数的变化。结果表明：温度由 25℃降至4℃,净光合速率（Pn）显著下降的同时,气孔导度(Gs)、蒸腾速率(Tr)、胞间CO2浓度（Ci）也显著下降,但气孔限制值(Ls)和水分利用效率(WUE)却显著增加,说明光合作用的下降主要由气孔因素引起;之后随温度下降至1 ℃,净光合速率、气孔导度、蒸腾速率、水分利用效率、气孔限制值均出现显著下降,但胞间CO2浓度却显著上升,说明光合作用的下降主要由非气孔因素引起。叶绿素荧光参数显示,随温度下降,初始荧光(Fo)不断上升,PSⅡ最大光化学效率（Fv/Fm）、光化学猝灭系数(qP)、非光化学猝灭系数（qN）不断下降,其中以4 ℃以下的低温胁迫,这些参数的变化最为显著。表明严重低温对油棕幼苗产生了显著的光抑制,过剩的激发能不能通过热耗散途径散失,大量积累于PSⅡ反应中心,使光合机构遭受了较大程度的破坏,最终导致油棕幼苗光合能力的急剧降低。     

Physiological responses to water stress and yield of winter wheat cultivars differing in drought tolerance

Moderate to severe drought (water stress) at the reproductive stage is common in the U.S. Southern High Plains (SHP), where wheat is grown as a major winter crop. The objective of this study was to better understand the physiological basis of drought tolerance in elite wheat cultivars. A 2‐yr glasshouse study was conducted using three cultivars (TAM 111, TAM 112 and TAM 304) and two water treatments (wet: adequate water and dry: water‐limited). Overall, TAM 111 and TAM 112 used more water for cumulative evapotranspiration (ET) and had more tillers and greater root mass and shoot mass compared to TAM 304. In the dry treatment, TAM 112 had 67% and 81% more grain yield than TAM 111 and TAM 304, respectively. Water use efficiency for grain (WUEg) and water use efficiency for biomass (WUEbm) were also greater in TAM 112 compared to the other cultivars in the dry treatment. The flag leaves in TAM 112 at mid‐grain filling stage (about 15 days after flowering) had lower stomatal conductance (Gs), intercellular CO₂ concentration (Ci), transpiration rate (Tr) and net photosynthetic rate (Pn), but higher photosynthetic water use efficiency (PWUE) than TAM 111 and TAM 304 under water stress. This study demonstrated a distinct role of gas exchange parameters in response to drought, and TAM 112 was more efficient than TAM 111 and TAM 304 in evolving physiological mechanisms to adapt to water stress.     

Low temperature induced changes in activity and protein levels of the enzymes associated to conversion of starch to sucrose in banana fruit

Storage at low temperature is the most frequently used method to extend the shelf life of banana fruit, and is fundamental for extended storage and transport over long distances. However, storage and transport conditions must be carefully controlled because of the high susceptibility of many commercial cultivars to chilling injury. The physiological behavior of bananas at low temperatures has been studied to identify possible mechanisms of resistance to chilling injury. The aim of this work was to evaluate differences in the starch-to-sucrose metabolism of a less tolerant and susceptible (Musa acuminata, AAA cv. Nanicão) and a more tolerant (M. acuminata × Musa balbusiana, AAB, cv. Prata) banana cultivar to chilling injury. Fruits of these cultivars were stored in chambers at 13 °C for 15 d, at which point they were transferred to 19 °C, where they were left until complete ripening. The low temperature induced significant changes in the metabolism of starch and sucrose in comparison to fruit ripened only at 19 °C. The sucrose accumulation was slightly higher in cv. Prata, and different patterns of starch degradation, sucrose synthesis, activity and protein levels of the α- and β-amylases, starch phosphorylase, sucrose synthase and sucrose phosphate synthase were detected between the cultivars. Our results suggest that starch-to-sucrose metabolism is likely part of the mechanism for cold acclimation in banana fruit, and the cultivar-dependent differences contribute to their ability to tolerate cold temperatures.     

Influence of hot water treatment on brown rot of peach and rapid fruit response to heat stress

Recent results on hot water as an alternative treatment open a new perspective in disease incidence reduction. In the present work peach fruit were wounded, inoculated with conidia of Monilinia laxa and 15 min, 3, 6, 12, 24 and 48 h after inoculation treated by dipping in hot water (HT) at 60 °C for 20 s. The effect of heat treatment on some cell wall genes involved in ripening such as β-galactosidase (β-GAL), pectin lyase (PL), polygalacturonase (PG) and pectin methyl esterase (PME), was analyzed by qRT-PCR. The expression levels of defense related genes, phenylalanine ammonia lyase (PAL) and chitinase (CHI), heat stress-related genes such as heat shock proteins 70 and 90 (HSP70, HSP90), and reactive oxygen species (ROS) scavenging genes were also evaluated by qRT-PCR. A 100% disease incidence reduction, as compared to untreated fruit, was obtained by treating 6 and 12 h after inoculation. Moreover, brown rot was inhibited by 85.7% when fruit were heat-treated 48 h after inoculation. The expression levels of cell wall genes (β-GAL, PL, PG and PME) showed a general decrease in HT fruit as compared to the control, whereas PAL, CHI, HSP70 and ROS-scavenging genes increased their expression level in HT samples with respect to the untreated ones. Our results show a curative activity of heat on peach inoculated with M. laxa 48 h before treatment. Each analyzed gene proved to be differentially expressed following heat treatment.     

Spawning of two Pomatoschistus species (gobbidae) in relation to nest availability and depth: A field experiment

The spawning of two sympatric gobiid fishes, the sand goby Pomatoschistus minutus and the common goby Pomatoschistus microps was investigated in relation to nest availability and depth. In two field experiments, carried out in the northern Baltic proper during summer, empty shells of the mussel Mya arenaria were divided into three size groups and provided as spawning substrates. The shells were set out at different depths and at different densities.Spatial habitat partitioning by depth was found. The sand goby preferred the deeper bottoms (2.8 m) and the common goby spawned only in areas shallower than 1 m. The spawning of the two species was separated in time by about 6 weeks with an overlap at the beginning of July. Low water temperatures (∼10°C) in June probably delayed spawning in the common goby.The sand goby preferred the larger shells. The larger the shells, the larger was the number of eggs, i.e. the male potential reproductive success. The common goby preferred the smaller shells, and their potential reproductive success did not show a clear trend with increasing shell size.In both species, the mean number of shells used for spawning increased with increasing substrate density. The maximum nesting density was 21 nests per m² for the sand goby and 20 nests per m² for the common goby. The maximum total density for both species together was 23 nests per m².Interspecific competition for spawning substrates was minimized, as spawning was separated in time and each species preferred different sizes of shell. The intensity of spawning under the shells provided indicates that a lack of suitable substrates limits spawning by both species in this area. The larger sand goby is limited in particular by the lack of larger substrates, and is probably forced to spawn in shallow water when suitable shells do not occur in its preferred depth range.