木薯内源赤霉素含量与块根淀粉积累的关系

为研究木薯(Manihot esculenta Crantz)内源赤霉素含量与不同淀粉含量木薯块根淀粉积累的关系,以木薯辐选01(块根淀粉含量高)和华南124(块根淀粉含量低)为材料,在木薯的4个生长时期测定其根、茎、叶的赤霉素含量以及块根淀粉含量,并进行相关分析。结果表明,在不同生长发育时期,木薯通过各部位的赤霉素水平调控淀粉合成关键酶活性来调节淀粉的合成。     

加工型马铃薯品种微型薯种薯贮藏期内源激素含量、阈值和休眠期相关性分析

【目的】加工型马铃薯微型薯作为生产高质量脱毒原种用种薯,其休眠持续时间和发芽时间有着重要的经济意义。探究加工型马铃薯微型薯种薯在不同贮藏温度下,随着贮藏时间延长,微型薯中内源激素含量与其休眠期的关系,可为加工型马铃薯微型薯种薯的高质量贮藏提供理论依据。【方法】采用高效液相色谱(HPLC)法,测定微型薯在3种不同贮藏温度(4℃、10℃、20℃)下连续贮藏150 d,其内源赤霉素(GA3)、吲哚-3-乙酸(IAA)和脱落酸(ABA)的含量,分析不同贮藏时间和温度下内源激素含量变化对微型薯休眠解除程度影响,并根据内源激素水平动态变化进行激素与休眠的相关性推导。【结果】在整个贮藏期(150 d)间,随着贮藏温度提高,两个品种夏波蒂和大西洋休眠解除时间显著缩短,在4℃贮藏150 d后,两个品种休眠均未完全解除,在10℃和20℃贮藏条件下,大西洋比夏波蒂休眠解除早15 d左右。在整个贮藏期(150 d)间,随着贮藏时间延长和贮藏温度提高,GA3含量显著上升,在10℃贮藏150 d时,大西洋和夏波蒂中GA3含量分别是4℃贮藏条件下的1.7和1.9倍,在20℃贮藏150 d时,大西洋和夏波蒂中GA3含量分别是4℃贮藏条件下的1.9和2.0倍。IAA含量在贮藏后期(90—150 d)显著上升,在10℃贮藏150 d时,大西洋和夏波蒂中IAA含量分别是4℃贮藏条件下的1.5和1.2倍,在20℃贮藏150 d时,大西洋和夏波蒂中IAA含量分别是4℃贮藏条件下的1.9和1.5倍。ABA含量显著下降,在4℃贮藏150 d时,大西洋和夏波蒂中ABA含量是10℃贮藏条件下的7.2和6.4倍。在整个贮藏期(150 d)间,(GA3+IAA)/ABA比值显著提高。对(GA3+IAA)/ABA比值与种薯发芽率相关性分析表明,(GA3+IAA)/ABA比值与种薯发芽率呈极显著线性正相关。根据(GA3+IAA)/ABA比值与种薯发芽率之间的线性关系推断出夏波蒂和大西洋休眠解除时,(GA3+IAA)/ABA临界阈值分别为52.02和48.49。当(GA3+IAA)/ABA比值超过临界阈值后,微型薯种薯的发芽率超过50%,休眠解除。【结论】微型薯中内源激素GA3、IAA和ABA含量动态平衡变化以及发芽率明显受贮藏时间和贮藏温度影响。通过对块茎内源激素比值和发芽率的相关性分析获得(GA3+IAA)/ABA临界阈值计算方法和范围,为加工型马铃薯种薯贮藏精准控制提供了理论依据和技术参数。     

自然干旱胁迫下配方肥增效剂对水稻内源激素的影响

 为揭示土壤自然干旱条件下配方肥增效剂对水稻植株内源激素的影响，以中稻培两优93为材料，采用盆栽法研究了配方肥增效剂对水稻内源脱落酸（ABA）、生长素（IAA）、赤霉酸（GA3）、玉米素核苷（ZR）的影响。干旱处理后，ABA在前期大量积累，后期呈下降趋势。根系和叶片中ABA含量大幅度升高，其中根系中ABA增幅达58~101倍，根源ABA积累幅度远高于叶源ABA积累幅度，而增效剂处理促进了ABA的积累。干旱胁迫前，增效剂处理水稻植株根系IAA、ZR和叶片GA3均显著高于对照；而干旱胁迫后，增效剂处理植株上述激素水平均大幅下降，而对照下降幅度较小。叶中IAA、ZR和GA3的变化则与根系相反。     

赤霉素对梨糖代谢及其关键酶基因表达的影响

为了研究赤霉素增强果实库强的机制,以‘翠冠’梨(Pyrus pyrifolia Nakai)为试材,研究了赤霉素(GA)处理下果实膨大过程中果糖、葡萄糖、蔗糖、山梨糖醇和可溶性总糖含量变化及山梨糖醇和蔗糖代谢关键酶基因转录水平的影响。结果表明,6-磷酸山梨糖醇脱氢酶基因(S6PDH)表达量前期较低,随着果实膨大逐渐升高,并且GA促进S6PDH在果实膨大中后期的表达;山梨糖醇代谢关键酶NAD-山梨糖醇脱氢酶基因(NAD-SDH)在果实膨大前期相对表达量很高,GA抑制了果实膨大前期NAD-SDH的表达。在蔗糖代谢中,酸性转化酶基因(SI)的表达量随着果实的膨大逐渐上升,在膨大中期达到高峰,然后开始下降,且果肉中SI表达量较果芯中的高,GA显著促进果实膨大期果实中SI的表达。果芯中蔗糖磷酸合成酶基因(SPS)表达量随着果实成熟而持续增加,果芯中表达水平较高于果肉中,GA显著提高果实膨大中后期SPS的表达水平。蔗糖合成酶基因(SS)在果实膨大前期和中期表达水平较高,GA处理抑制SS表达。GA处理显著提高梨果肉和果芯组织中的可溶性糖含量,GA诱导糖代谢相关酶的基因的表达,并在果芯和果肉中存在空间表达差异。     

Blackspot injury of film-wrapped potatoes in relation to bruising and respiratory gases

Summary Film-wrapped potatoes were compared with non-wrapped potatoes for blackspot susceptibility. Individual ‘Russet Burbank’ potatoes wrapped in Cryovac D-955 shrink film were less susceptible than non-wrapped potatoes to internal blackspot injuries when stored at 24°C. The film wrap reduced potato weight loss (water loss) but it did not alter the rate of respiration or the endogenous oxygen or carbon dioxide levels. Thus the reduced susceptibility to blackspot could not be related to reduced oxygen levels much as would inhibit the activity of polyphenol oxidase, the enzyme responsible for the development of internal blackspot. In addition to high suscetibility to internal blackspot, the non-wrapped potatoes shrivelled at 24°C and lost their marketable appearance.     

核桃花芽生理分化研究进展

从分化时间段的确定、分化时期内源物质的含量及变化、分化时期外源物质的调控等方面,对有关核桃花芽生理分化研究进行了归纳.①在生理分化期上,雌花芽为5月上旬至6月上旬;雄花芽结束时间在3月下旬;雌花芽生理分化雌先型早于雄先型,雄花芽生理分化雄先型早于雌先型.②分别总结了雌花芽和雄花芽生理分化期的内源多胺、内源激素、内源营养物质(淀粉、蛋白、糖)的含量及变化趋势,以及POD对核桃雌雄花芽分化的推动作用.③在外源物质调控花芽生理分化上,雌花芽分化期合理喷施外源多胺、生长抑制剂(B9、CCC、PP333)能显著促进雌花分化,雄花芽生理分化期合理期喷施整型素能显著减少雄花芽分化量.     

金雀花扦插生根过程中内源激素动态变化

以2年生金雀花实生苗硬枝为试材,应用酶联免疫吸附测定法（ELISA）,研究金雀花硬枝在扦插生根过程中内源激素含量的变化,旨在揭示金雀花扦插生根机理。结果表明：900 mg/ L 吲哚乙酸（IAA）处理金雀花插穗较CK 显著缩短生根时间;不定根大量形成前,除脱落酸（ABA）外,其他均呈倒“V”形变化;内源激素变化曲线的峰值（或谷值）出现前,IAA 处理的 IAA 含量、IAA/ ZT（细胞分裂素）、IAA/ ABA、ZT/ ABA 均高于 CK,ABA 含量低于 CK;IAA 处理与 CK 内源激素的峰值（或谷值）分别出现在第10天和第15天,与其生根动态具有协同性。     

Circadian melatonin release <Emphasis Type="Italic">in vitro</Emphasis> by European sea bass pineal

Melatonin production by the fish pineal is under the control of photoperiod. In addition, in some fish species pineal melatonin production is self-sustained by an intrapineal circadian pacemaker, not in salmonids, though. The aim of this research was to test melatonin release in vitro by the pineal of sea bass held under LD 12:12 and DD conditions to determine the endogenous nature of melatonin rhythm. Circadian rhythmicity ( = 28.3 h) was found since rhythmic melatonin release persisted on DD.     

Effects of temperature changes on the endogenous rhythm of oxygen consumption in the Japanese flounder <Emphasis Type="Italic">paralichthys olivaceus</Emphasis>

ABSTRACT:   The effects of temperature changes on the endogenous rhythm of oxygen consumption in the Japanese flounder Paralichthys olivaceus which were acclimated to 3, 14 or 20°C in advance were investigated. The oxygen consumption rate (OCR) of individuals (total length >28 cm) that were acclimated to 3°C, maintained a relatively low value of 6.9 ± 2.3 mL (mean ± SD) O₂/kg ww (wet weight)/h till 5.8°C, which is considered a 'minimum' rate. Thereafter, the OCR gradually increased up to 18.7 mL O₂/kg ww/h at the temperature of 10.6°C. The OCR of individuals acclimated to 14°C stabilized with 124.2 ± 24.1 mL O₂/kg ww/h, when tested at the relatively constant temperature of 14.4 ± 0.17°C. Maximum entropy spectral analysis revealed that the peak OCR occurred at 23.9 h intervals, which could be a circadian rhythm. The mean OCR showed a peak at 06.00–08.00 hours. For the temperature above 25°C in which the fish were acclimated to 20°C, the rhythmic patterns of OCR were observed until the experimental temperature reached 26.4°C. For the temperature above 28.4°C, the metabolic activity rhythm of the OCR was dampened and then the OCR abruptly rose again. It is assumed that the oscillator of the endogenous rhythm lost the governing of normal metabolic activity in Japanese flounders above 28.4°C. These results suggest that the temperatures of around 5.8, 26.4 and 28.4°C are the 'lower limit temperature', 'upper incipient lethal temperature', and the 'critical thermal maximum', respectively, for the endogenous rhythm of oxygen consumption in the Japanese flounder.     

Rearing conditions influence nutrient availability of plant extracts supplemented diets when fed to broiler chickens

The effects of a standardised mixture of essential oils, including 5% carvacrol, 3% cinnamaldehyde and 2% capsicum (XT 6930; Pancosma S.A), on dietary apparent metabolisable energy corrected for nitrogen retention (AMEn), nutrient digestibility and mucin secretions, measured as sialic acid (SA) were investigated in broilers fed on the same diet but reared under different conditions, that is, cages and floor pens littered with wood shavings used in previous broiler study. The use of XT reduced (p < 0.05) nitrogen digestibility (0.585 vs. 0.544) and tended (p = 0.072) to reduce dry matter digestibility (0.733 vs. 0.717) of the diet when fed to birds reared in cages. However, XT supplementation improved (p < 0.05) fat digestibility (0.844 vs. 0.862) and tended (p = 0.093) to increase AMEn (14.01 vs. 14.25 MJ/kg DM) of the same diet when fed to broilers reared in floor pens. Essential oils supplementation tended (p = 0.059) to increase the secretion of SA, when fed to birds reared in cages (11.24 vs. 14.18 μg), but did not influence (p > 0.05) the SA secretion from birds reared in floor pens. The results obtained from the cage study tend to be the opposite of those obtained from the floor pen study. This suggests that the efficiency of dietary plant extracts may be influenced by the rearing/hygienic conditions of poultry. Based on the overall results, it can be concluded that information on rearing conditions should be taken into account for more complete interpretation of the experimental data emanating from experiments involving use of essential oils typified by those considered in this study.