Generation of Hydrogen from Photolysis of Organic Acids by Photosynthetic Bacteria

Photodecomposition of ten kinds of organic acids by Rhodopseudomonas palustris for producing hydrogen has been investigated. By using acetate as hydrogen donor, dynamics of hydrogen production and cell growth has been determined; the influences of acetate concentration, temperature, light intensity and the effects of the interaction among metal ions (Fe3+, Ni2+), acetate and glutamate in aqueous solution on hydrogen production have been examined for optimizing the conditions of H2 generation. The results show that H2 production is partially correlated with cell growth; Ni2+ inhibits hydrogen production, but enhances cell growth; Fe3+ promotes hydrogen production evidently. The highest rate of H2 production is 22.1 mL L-1 h-1 under the conditions of 35 ~ 37℃, 6000 ~ 8000 lx, 30 mmolL-1 of acetate, 9 mmolL-1 of glutamate, and 50 mmolL-1 of Fe3+.

Comparison of anatomical structure and photosynthetic characteristics between the two photosynthetic organs of the desert plant Hedysarum scoparium

The desert plant Hedysarum scoparium uses leaflets and rachises as its photosynthetic organs. The abundance of leaflets was lower under unfavorable environmental conditions and higher with improved water conditions. To examine the characteristics associated with the adaptation of H. scoparium to its environment, we selected plants with both compound leaves and rachis without leaflets to study the anatomical structures and gas exchange characteristics of the two organs. The results show that the water storage tissues in rachises were more developed compared with the leaflets. The diurnal courses of the net photosynthetic rate for the rachis and the leaflet were both in a bimodal pattern. Meanwhile, both two peak values of the rachis were significantly higher than those of the leaflet. The daily average transpiration rate was significantly higher in the rachis than in the leaflet in order to lower the temperature of the rachises. It was concluded that under desert drought conditions, the leaflets of H. scoparium were partially or completely degraded to reduce the transpiration area as an adaptive response to water deficit, and only the rachises were retained as photosynthetic organ. The rachises were found to be better suited to a desert habitat than the leaflets.

The spike weight contribution of the photosynthetic area above the upper internode in a winter wheat under different nitrogen and mulching regimes

Besides leaves, non-foliar green organs such as stem and spike are also considered photosynthetic organs. To assess the photosynthetic contributions of these organs, the correlations between these photosynthetic areas and single-spike weight were investigated in a winter wheat(Triticum aestivum L.) under four nitrogen and mulching treatments: N120,N150, N195, and N195 + M. Two-year repeated field experiments were conducted on the Loess Plateau of China. Non-foliar photosynthetic area, grain-filling ratio and duration,grain yield, and in particular, single-spike weight, were measured, recorded and analyzed.Under the N195 + M treatment, plants showed the largest area of photosynthetic organs(flag leaf and non-foliar organs) and the highest grain yield and single spike weight. Singlespike weight was positively correlated with the areas of all examined non-foliar photosynthetic organs, in particular with the area above the flag leaf node(R^2= 0.761*)and the area above the exposed part of the peduncle(EXP)(R^2= 0.800**). In addition, singlespike weight was highly correlated with average grain-filling ratio(R^2= 0.993**), whereas it was less highly correlated with grain-filling duration(R^2= 0.533). The morphological traits of non-foliar photosynthetic organs were also more highly correlated with average grainfilling ratio than with average grain-filling duration. The significant correlation between each of the morphological traits(area, length and width) of EXP and single-spike weight indicates that morphological traits of EXP are important in determining spike weight in the Loess Plateau environment.

Oxidative metabolism of photosynthetic species and the exposure to some freshwater and marine biotoxins

Environmental climate conditions could lead to an increasing global occurrence of microorganism blooms that synthesize toxins in the aquatic environments.These blooms could result in significantly toxic events.Responses of photosynthetic organisms to adverse environmental conditions implicate reactive oxygen species generation;but,due to the presence of a varied cellular antioxidant defense system and complex signaling networks,this oxidative stress could act as an important factor in the environmental adaptive processes.The objective of this review was to assess how some biotoxins are implicated in the generation of oxidative and nitrosative metabolic changes,not only in biotoxin-producing organisms but also in non-producing organisms.Therefore,toxins may modify the oxidative cellular balance of several other species.Hence,the effect of toxins on the oxidative and nitrosative conditions will be evaluated in freshwater and marine algae and vascular plants.The changing climate conditions could act as agents capable of modifying the community composition leading to alterations in the global health of the habitat,risking the survival of many species with ecological relevance.

减量灌水及有机无机肥配施对西北灌区玉米光合生理、籽粒产量及品质的影响

针对绿洲灌区玉米生产中普遍水肥投入大、利用效率低等问题,通过研究不同灌水量和有机无机肥等氮配施对玉米光合生理、籽粒产量和品质的影响,以期获得最佳的灌水水平和有机无机肥等氮配施比例。2021—2022年,在绿洲灌区采用两因素裂区试验设计,主区为2个灌水水平(传统灌水和减量20%灌水),副区为5个有机无机肥等氮配施比例(全施无机氮肥、75%无机氮肥+25%有机肥、50%无机氮肥+50%有机肥、25%无机氮肥+75%有机肥和全施有机肥),探究玉米光合生理、籽粒产量和品质对不同水氮管理模式的响应特征。结果表明,与传统灌水(I2)相比,减量20%灌水(I1)降低了玉米叶面积指数(leaf area index,LAI)、光合势(photosynthetic potential,LAD)、净光合速率(Pn)、蒸腾速率(Tr)和气孔导度(Gs),提高了胞间CO_(2)浓度(Ci)、籽粒蛋白质含量和籽粒苏氨酸含量;有机无机肥配施对玉米光合生理指标、籽粒产量和品质都有显著影响,随有机肥比例增加,有机无机肥配施对玉米的影响会逐渐从正效应变为负效应;与传统灌水结合全施无机氮肥(I2F1)相比,减量20%灌水结合75%无机氮肥+25%有机肥(I1F2)玉米平均叶面积指数(mean leaf area index,MLAI)提高了6.9%~7.1%,总光合势(total photosynthetic potential,TLAD)无显著变化;玉米吐丝期-蜡熟期LAI提高了5.0%~11.4%,吐丝期-蜡熟期LAD提高了7.5%~9.1%。I1F2较I2F1提高了玉米抽雄期-蜡熟期叶绿素含量(chlorophyll content,SPAD)、Pn、Tr和Gs,降低了Ci。2年内I1F2较I2F1玉米增产12.0%~12.5%,籽粒中蛋白含量提高了6.9%~18.9%,籽粒中苯丙氨酸、赖氨酸、苏氨酸、色氨酸、亮氨酸、异亮氨酸和缬氨酸含量分别提高了29.6%~43.3%、77.7%~93.3%、49.7%~51.5%、18.4%~28.6%、39.5%~46.0%、57.4%~78.1%和35.1%~41.3%。其他处理对玉米光合生理、籽粒产量及品质指标也有一定影响,但综合2年结果,I1F2影响更显著。因此,减量20%灌水(3240 m^(3)hm^(–2))结合75%无机化学氮肥(270 kg hm^(–2))配施25%有机肥(90 kg hm^(–2))是实现西北灌区玉米高产优质生产目标的适宜水氮管理模式。

喀斯特地区水生光合生物群落结构组成及其对微量元素的影响

微量元素是影响喀斯特地表水体水质的重要因素,水生光合生物在光合代谢过程中能够吸收并去除部分有害元素,然而关于不同水生光合生物群落结构组成对微量元素的吸收效果和去除潜力如何目前则少有研究。基于普定喀斯特生态系统国家野外观测站的野外监测、系统采样和实验测定以及统计分析,构建了由裸岩地、裸土地、耕地、草地和灌丛地5种土地利用组成的植被-土壤-地下水-地表水模拟生态系统,并以其中的地表水生生态系统为研究对象,开展了水生光合生物群落结构组成对微量元素去除潜力及控制机制的研究。结果表明:①地表水水化学和水生光合生物量受季节变化与土地利用类型影响显著;②Cr,Mn,Co,Ni,Fe和Zn 6种微量元素浓度在不同喀斯特水生光合生物系统中存在显著差异,浮游-沉水共存系统对Mn,Co,Ni,Fe和Zn的吸收和去除能力优于单一浮游系统;③喀斯特地区的自然植被恢复(灌丛地和草地)促使地表水体形成的高溶解性无机碳(DIC)环境,有利于沉水植物生长,从而提高了对地表水体中Mn,Co,Ni,Fe和Zn等微量元素的去除潜力。这些认识将有助于岩溶区地表水体水生光合生物群落结构对地表水体微量元素调控机制的研究。

叶面喷水影响芒果叶片“午休”的转录组分析

【目的】通过组学技术研究持续喷水处理对芒果叶片产生的影响,揭示喷水处理影响“午休”的分子机制,进一步优化喷水处理条件,为达到最佳效果提供科学依据,并对提高芒果产量和品质以及响应国家减肥增效政策具有理论意义。【方法】以元江“台农一号”芒果为材料,对坐果期芒果在“午休”时段(12:30—14:10)喷水3次,每次喷水20 min,间隔20 min,以不喷水为对照,并以2组3个不同时期叶片进行Illumina Hi SeqTM 6000高通量转录组测序分析,用GO和KEGG数据库分析“午休”时段喷水和不喷水处理的差异表达基因(DEGs)。用差异表达基因分析工具(DESeq)对基因表达进行差异分析,以|log_(2)α_(FC)|>1,P<0.05为筛选差异表达基因的条件。【结果】3个时期分别获得3789,2885,1667个差异表达基因。GO分析表明差异基因与细胞组分分类中的膜、膜的固有成分、膜的组成成分等密切相关,KEGG分析差异表达基因主要富集在植物激素信号转导、植物MAPK信号通路、植物昼夜节律、氨基糖和核苷酸糖的代谢、类黄酮生物合成、光合生物碳固定、角质和亚硫酸盐及蜡的生物合成、卟啉和叶绿素的代谢、淀粉和蔗糖代谢以及甘油酯质代谢等途径。根据富集结果筛选8个差异表达基因,经实时荧光定量验证,基因表达趋势与转录组测序结果相符。【结论】CAO和POR基因表达延后,表明喷水处理可延长叶绿素的合成时间;FBP和SBP的基因表达略微降低,表明叶面喷水调控基因的表达量降至缓解芒果“午休”的最适范围内,有利于树体积累碳同化物,从而提高光合效率。

畜禽粪便施用对红壤铝胁迫下油菜幼苗生长及光合荧光特性的影响

【目的】红壤铝毒是限制作物生长的主要因素,畜禽粪便等有机物料作为改善土壤酸度和推动国家化肥零增长行动计划的重要途径之一,其对铝毒胁迫下作物生长及光合荧光特性的影响及其机理研究具有重要意义。【方法】利用盆栽试验,探究不施畜禽粪便(CK)、施用猪粪10 g·kg^(-1)(P10)、猪粪30 g·kg^(-1)(P30)、猪粪50g·kg^(-1)(P50)、鸡粪10 g·kg^(-1)(C10)、鸡粪30 g·kg^(-1)(C30)、鸡粪50 g·kg^(-1)(C50)、鸡粪猪粪各15 g·kg^(-1)(PC15)等8个处理对酸性土壤铝毒胁迫下油菜(Brassica napus L.)生物量、光合作用参数和叶绿素荧光特性的影响。【结果】在土壤铝毒胁迫下,不同畜禽粪便处理均促进了油菜幼苗地上部生物量、光合色素含量、光合作用和叶绿素荧光特性,在第80天各处理均显著大于对照组(P<0.05),表明畜禽粪便有效缓解红壤铝胁迫对油菜幼苗生长的毒害作用。施用等量鸡粪处理比猪粪更有利于促进油菜幼苗地上部生物量、光合色素含量,但对光合作用参数、Fv/Fm值和qP的促进作用较弱,而且鸡粪、猪粪混施处理光合色素含量、光合参数Tr、Gs、Ci、qN均大于单施处理(P<0.05),说明高pH值的鸡粪更利于促进油菜生长,而高养分含量的猪粪更利于促进油菜光合荧光特性。【结论】猪粪施用量50 g·kg^(-1)对油菜生长及光合荧光特性的铝毒胁迫缓解作用最佳,而鸡粪最佳施用量为30g·kg^(-1)。就油菜幼苗生长和光合荧光特性而言,畜禽粪便种类筛选、最佳用量确定并结合土壤酸度调控对缓解红壤铝毒至关重要。

有机肥替代化肥对马铃薯生长生理特性及产量的影响

【目的】从光合特性、抗氧化酶活性变化等方面揭示有机肥替代化肥影响产量的主要机制,以期为陇中旱农区马铃薯绿色生产提供理论依据。【方法】设置单施化肥(T1),50%有机肥代替化肥(T2),25%有机肥代替化肥(T3)和不施肥(T4,对照)4个处理,研究不同处理对马铃薯生长发育、光合生理特性及产量的影响。【结果】T2处理显著促进马铃薯的生长,T2处理50%替代比例下叶面积指数、叶绿素a、叶绿素b和叶绿素a+b较T4处理分别显著增加112.5、50.82、82.86和57.59%,有机肥替代化肥增加了块茎膨大期与淀粉形成期的超氧化物歧化酶活性,降低了丙二醛含量,其产量较T1和T4处理增幅为7.89%和28.37%。T2处理通过优化叶面积指数、叶绿素含量和光合特性之间的关系,提升叶片抗氧化酶活性,延缓了植株衰老,增加了叶片的光合效率与干物质的有效转运,提高了产量。【结论】50%有机肥替代化肥是适宜该区的科学替代比例。

不同施肥措施臭氧浓度升高对不同水稻品种光合特性的影响

近地层臭氧(O_(3))已严重威胁到作物生产,而施肥可以调节土壤的养分平衡,进而促进作物生长。以两个水稻品种(徽两优898和南粳9108)为研究对象,利用开顶式气室,设置2个O_(3)浓度处理(NF:环境大气为对照;NF40:环境大气+40 nmol/mol O_(3)),每个O_(3)处理下嵌套设置3个肥料处理(Ino:施无机肥处理,270 kg N hm^(-2) a^(-1);Red:减施无机肥30%处理,189 kg N hm^(-2) a^(-1);Com:有机无机肥配施处理,Red+有机肥鸡粪5000 kg hm^(-2) a^(-1)),通过测定不同生育期水稻光合参数,探究不同肥料处理下O_(3)对水稻不同生育阶段光合生理的影响。结果表明,NF40对水稻营养生长阶段的饱和光合速率(A_(sat))没有显著影响,而显著地降低了水稻灌浆期的A_(sat)。基于两个水稻品种的A_(sat)和相对叶绿素含量(SPAD)相对减少量与O_(3)累积剂量关系的斜率,发现杂交稻徽两优898(A_(sat)和SPAD的斜率:-1.55和-0.98)比常规稻南粳9108(A_(sat)和SPAD的斜率:-0.92和0.06)对O_(3)更敏感。此外,基于不同O_(3)处理下水稻的气孔导度(g_(s))和胞间二氧化碳浓度(C_(i)),可以看出O_(3)造成南粳9108光合速率降低的主要是非气孔因素,而徽两优898光合的降低是由气孔因素和非气孔因素共同限制。与Ino处理相比,Red处理主要通过降低叶片SPAD进而显著地抑制两种水稻品种的A_(sat),但Ino处理和Com处理间A_(sat)没有显著差异,说明有机无机肥配施能部分缓解减施无机肥造成水稻光合的降低。O_(3)和肥料处理对两个水稻的所有光合参数都没有显著的交互影响,表明短期有机无机肥配施并不能有效缓解O_(3)对作物造成的负面影响。在O_(3)污染背景下,研究结果可以为通过合理的农田氮肥管理措施减缓O_(3)造成的作物减产提供理论依据。

地表水中草甘膦暴露及其对水生光合生物毒性测试研究进展

随着草甘膦使用量的持续增加,水体中草甘膦的大量累积和潜在危害已经引发了人们的重点关注。在施用过草甘膦地区的水体中,出现了水生植被物种丰富度下降、覆盖度降低等状况。本文系统整理了地表水中草甘膦的来源、迁移转化和残留现状,基于草甘膦对浮游藻类、漂浮植物、挺水植物和沉水植物的生物毒性测试结果,分别阐述了草甘膦对这几种水生光合生物的急性和慢性毒性。毒性测试结果表明水生光合生物对草甘膦具有一定的耐受性,其对草甘膦的敏感度具有差异性。与浮游藻类、漂浮植物和挺水植物相比,沉水植物对草甘膦更为敏感。在此基础上,对草甘膦作用下水生光合生物的毒性测试结果进行了总结与展望,旨为草甘膦对水生光合生物的生态风险评估提供科学依据。

青藏高原野生宽叶羌活根际土壤微环境变化对光合作用的影响

为进一步研究青藏高原野生宽叶羌活药材形成对土壤环境的响应特性,明确土壤环境在宽叶羌活不同生长年限的差异,以不同生长年限野生宽叶羌活根际土壤为试验材料,研究根际土壤酶活性和有机碳含量的变化规律。结果表明,宽叶羌活对根围土壤孔隙度的影响主要在土层0~40cm深处,5年生地块平均土壤孔隙度减小至对照的88.56%,对土层50~100cm处影响较小。土壤含水量在土层0~50cm处变化显著,前3年根围土壤含水量逐年增大,达到对照的105.59%,土层60cm以下的土壤水分含量变化规律一致且差异不显著。土壤有机碳含量逐渐下降,从对照到5年生地块,土壤总有机碳含量降低到原来的41.75%,其中,可溶性有机碳含量降低到原来的51.78%,颗粒有机碳含量降低到原来的18.30%,活性有机碳含量降低到原来的24.42%,易氧化有机碳含量降低到原来的21.76%,微生物量碳含量降低到原来的47.31%;可溶性有机碳含量在3年生和5年生土壤间差异不显著,活性有机碳和易氧化有机碳含量在2年生和3年生土壤间差异不显著。随着生长年限增长,土壤脲酶、多酚氧化酶和过氧化氢酶活性呈先降低后升高的变化趋势,土壤脱氢酶和蔗糖酶活性没有明显变化趋势,土壤磷酸酶活性呈显著升高的变化趋势。随着株龄增大,叶片表观量子效率显著减小,光补偿点、光饱和点和暗呼吸速率均显著增大;叶片的原初光能转换效率、光化学淬灭系数和光合电子传递效率均表现不同程度的减小,非光化学淬灭系数表现显著增大,综合分析表明,随着生长年限的增加,土壤理化活性和部分土壤酶及有机碳含量降低,土壤微环境对根系生物活性的影响作用增大,根系生存环境的变化影响植株对土壤水分和营养物质的吸收,植株叶片同化效率降低,进而影响宽叶羌活药材质量和品质形成。

基于光合细菌红假单胞菌的废水处理与协同固碳作用研究

为探讨光合细菌在废水处理和协同固碳作用中应用的可行性,利用红假单胞菌处理废水,研究其在处理时间120 h内对废水的化学需氧量(COD)的去除能力,并在处理过程中通过通入CO_(2)研究红假单胞菌对废水处理与协同固碳的能力。结果显示:红假单胞菌在有氧有光条件下,光合微生物处理效果最佳,400 mL模拟废水中添加的红假单胞菌浓度为0.5 g/L,处理120 h,废水COD值由2753.50 mg/L降低至185.57 mg/L。红假单胞菌不仅能有效处理废水,显著降低废水COD值,同时能实现对CO_(2)的固定。

Effect of organic fertilizers used in sandy soil on the growth of tomatoes

In order to reveal the regulating capacity of organic fertilizers on sandy soil, pots experiments were carried out. The growth of tomatoes planted on sandy soil amended by organic fertilizers was measured. Organic fertilizers can be helpful to improve the plant height, stem diameter, the aerial parts fresh weight, root fresh weight, leaf photosynthetic rates and photosynthesis, and lay a good foundation for the growth of ??tomatoes. The effect of organic fertilizer is the most significant. Among all the treatments of adding 2.5%, 5%, 10% organic fertilizers, adding 10% organic fertilizers are the best. It can significantly enhance the growth and photosynthesis of tomatoes, and it is among the best of these three soil treatments for sandy soil.

Exploration of Distinct Physiological and Biochemical Alterations in Chickpea (Cicer arietinum L.) under Varying Organic Materials, Drought and Proline Application

Chickpea yield is decreasing day by day due to drought stress,which could be an immense risk for future food security in developing countries.Management practices could be the most excellent approach to diminish loss due to this abiotic factor.The current research work was designed to explore the tolerance reaction of chickpea genotypes against management practices,through morphological and biochemical parameters and evaluate yield performance across drought prone location of Bangladesh.Four genotypes BD-6048,BD-6045,BD-6090,BD-6092 and eight management practices,e.g.,severe water stress(SWS),i.e.,without irrigation,10 cm thick mulching with rice straw(MRS),10 cm thick mulching with water hyacinth(MWH),organic amendment through compost(OAC)@3 t ha−1,organic amendment through cow dung@5 t ha−1(OACD),organic amendment through poultry manure@2 t ha−1(OAPM),inorganic amendment through proline application(IAPA)as foliar spray and 16 h hydro-priming(HP).The study revealed that the genotypes BD-6048 showed excellent performance because of the highest chlorophyll,carotenoids,phosphorus,potassium,proline and protein content.The highest pod number plant−1 also increased seed yield in BD-6048.Considering management practices,IAPA increased relative water content,carotenoids,leaf phosphorus and potassium compared to other management practices and severe water stress.Finally,BD-6084 was selected as best genotype because of a significant increase in chlorophyll a and b,carotenoids,and relative water content with IAPA.Identified top performing genotypes can be used for releasing variety and cultivated for sustainable production in drought prone area of Bangladesh.

腐植酸有机肥对灵武长枣光合荧光参数及果实品质的影响

【目的】为灵武长枣施肥管理提供参考。【方法】以灵武长枣Ziziphus jujuba cv.Lingwuchangzao为研究对象,采用单因素随机区组设计,设置4个腐植酸有机肥施用水平,分析不同处理之间叶片氮素含量、叶绿素相对含量、净光合速率、叶绿素荧光参数及果实品质的差异。采用主成分分析法对各处理的施肥效果进行综合评价。【结果】与对照相比,施用腐植酸有机肥显著提高了叶片铵态氮的含量,增加了6.07%~8.08%;叶绿素相对含量和净光合速率随着施肥量增加而提高,由高到低依次均为T3、T2、T1、CK;施肥后,F_(m)、F_(v)/F_(m)、F_(v)/F_(o)、E_(To)/R_(C)、R_(C)/C_(Sm)、E_(To)/C_(So)、φ_(Eo)、I_(P)有不同程度的升高,F_(o)、A_(BS)/R_(C)、D_(Io)/R_(C)、T_(Ro)/R_(C)、φ_(Do)有不同程度的降低,其中T3处理的Fv/Fm和IP显著高于对照;与对照相比,果实纵径、单果质量、可溶性固形物含量、维生素C含量显著增加,其中纵径和单果质量的增幅分别为5.41%~8.13%、11.15%~12.91%,可溶性固形物含量随着施肥量增加呈现增加趋势,增加了3.03%~7.52%。【结论】单株施用1.5 kg腐植酸有机肥、0.3 kg尿素、0.3 kg过磷酸钙、0.2 kg硫酸钾的效果最佳,有利于灵武长枣光合性能和果实品质的改善。

光合细菌叶面肥喷施对设施有机番茄产量和品质的影响

【目的】研究设施番茄盛果期叶面喷施光合细菌叶面肥对其产量及品质的影响,为设施番茄高效生产及叶面施肥提供参考依据。【方法】以中研868番茄品种为研究对象,选择3个设施大棚,设置光合细菌组、鱼蛋白组、清水对照(CK,不施叶面肥)共3个处理,于番茄盛果期开始每7 d叶面喷施1次,共计喷施4次,测定各处理前和处理后不同时间段内番茄叶片叶绿素含量,净光合速率,叶片病害指数,产量和品质等指标。【结果】与对照组叶绿素含量持续下降趋势相比,喷施光合细菌和鱼蛋白后7~14 d均能提高番茄叶片叶绿素含量,之后叶绿素含量均有所下降,但光合细菌组下降幅度最低;叶绿素含量的下降与番茄叶片的病害指数呈现出显著正相关性,光合细菌组叶面白粉病全程发病指数最低,而鱼蛋白组在前14 d发病指数相对较低,而14 d之后发病指数较高,对照组发病最为严重。光合细菌组和鱼蛋白组净光合速率前14 d显著增加,之后有所降低,其中光合细菌组增加幅度最大并且下降幅度最小,对照组呈现出线性下降趋势;与对照组相比,光合细菌组番茄品质最佳,其中可溶性糖增加了62.5%,抗坏血酸提高了81.7%,平均单株产量增产率达到了33%,而鱼蛋白组仅在总酸上显著提高,其他指标提升差异不显著。【结论】设施有机番茄盛果期叶面喷施光合细菌叶面肥品质和增产效果最佳,其主要机理可能是通过减缓番茄老叶叶绿素的降解以及抑制番茄叶面白粉病的发生和发展而实现的。

沼泽红假单胞菌产类胡萝卜素及抗氧化性

类胡萝卜素是一种应用广泛的脂溶性天然色素和抗氧化剂。本文以一株典型的紫色非硫光合细菌——沼泽红假单胞菌(Rhodopseudomonas palustris)为实验对象,研究了光照厌氧体系下有机酸碳源种类、盐浓度和光照强度等培养条件对其生长和产类胡萝卜素量及组成的影响,并探究了类胡萝卜素的抗氧化性。研究结果表明:在实验的8种有机酸中,以乳酸为碳源可获得最高生物量以及类胡萝卜素含量;产类胡萝卜素最适光照强度(500lx)低于该菌生长所需(2000lx);高盐浓度(7.5g/L)可促进该菌合成类胡萝卜素,是其生长所需最佳盐浓度的三倍。在优化后的培养条件下,该沼泽红假单胞菌类胡萝卜素含量可达15.35mg/L。所产类胡萝卜素由6种组成,培养条件对其组成有明显影响,高盐浓度和强光照会促进3,4-脱氢玫红品(3,4-didehydrorhodopin)的合成,可能是光合细菌应对环境压力的一种机制。抗氧化性分析和数据拟合表明不同组成的类胡萝卜素抗氧化能力差异显著,经基螺菌黄素和3,4-脱氢玫红品的抗氧化能力最强。

遮穗和去颖下燕麦穗部特征变化和穗部光合贡献率估算

随着探索提高植物整体光合能力相关研究的不断开展,麦类作物穗部器官等植物非叶绿色器官光合潜力挖掘逐渐得到关注。本研究在成都平原秋播美达、贝勒、莫尼卡、摄政王、泰克和甜燕60等6个品种燕麦,设置遮穗、去颖2个试验处理,比较分析了各品种间穗部特征、穗部光合贡献率、颖片光合贡献率和茎光合物质转移率等差异。结果表明,燕麦穗部器官光合贡献率为28.56%~49.05%,其中甜燕60最高;6个品种燕麦的颖片光合贡献率为11.03%~36.88%,茎光合物质转移率为6.65%~35.81%。燕麦穗部器官对籽实增重表现了较高的光合贡献,当燕麦穗部器官光合受到限制时,燕麦单粒种子重和单穗种子数显著降低,尤其是影响双粒小穗数。

长期复种绿肥下光合碳在水稻-土壤系统中的分配与稳定

冬季复种绿肥是我国南方稻区传统的培肥增产模式,探究长期冬种绿肥下光合碳在水稻-土壤系统中的分配规律,对深入解析稻田土壤碳循环、充分发挥绿肥的生态功能具有重要意义。基于稻-稻-绿肥复种长期定位试验(38年),针对稻-稻-紫云英、稻-稻-油菜和稻-稻-休闲三种处理,采用^(13)C-CO_(2)脉冲标记技术,研究长期冬季复种绿肥下光合碳在早稻季分蘖期水稻-土壤系统中的分配特征。结果表明,与冬季休闲处理相比,复种紫云英和油菜处理使早稻地上部^(13)C-光合碳积累量每穴分别增加19.9 mg和80.6 mg;复种紫云英处理使早稻地下部^(13)C-光合碳积累量每穴降低2.7 mg,而复种油菜处理对早稻地下部^(13)C-光合碳积累量无显著影响。同时,冬季复种紫云英和油菜减少了早稻^(13)C-光合碳向土壤的分配,积累量每穴分别降低7.6 mg和7.8 mg;复种紫云英处理对水稻^(13)C-光合碳在土壤颗粒有机碳(POC)和矿物结合态有机碳的分配比例无显著影响,复种油菜处理促进了水稻^(13)C-光合碳向土壤POC中的分配,使^(13)C-POC的占比增加35.3%。综上,长期复种绿肥促进了水稻分蘖期光合碳在水稻-土壤系统中的积累,与冬季休闲处理相比,冬季复种绿肥使光合碳在水稻-土壤系统中积累量增加3.7%~28.0%;增加了光合碳向水稻地上部的分配,减少了其向水稻地下部及土壤中的分配比例;且复种油菜处理减弱了土壤中水稻光合碳的稳定性;从增加有机碳总量和光合碳稳定性的角度可知,复种紫云英是相对较好的一种冬季复种绿肥模式。