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.

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.

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。

等氮量有机肥替代化肥对绿洲灌区糯玉米光合特性及品质的影响

通过田间定位试验探究等氮量有机肥替代化肥比例对糯玉米光合特性和营养品质的影响,以‘京科糯2000’为试验品种,在施纯氮总量为300 kg·hm^(-2)定额条件下,采用随机区组设计,设全施化肥(F1),有机肥替代25%(F2)、50%(F3)、75%(F4)化肥和全施有机肥(F5)5个处理,测定了糯玉米抽雄期光合特性、鲜穗期籽粒营养品质及鲜穗产量。结果表明:等氮量有机肥替代部分化肥能显著提高糯玉米抽雄期的光合性能,其中F2和F3处理较F1处理的SPAD值提高10.6%~14.3%,T_(r)提高11.7%~18.8%,P_(n)提高11.2%~17.1%,G_(s)提高62.2%~79.2%,C i降低22.7%~23.8%。F2处理糯玉米鲜穗产量较F1处理显著提高10.4%。等氮量有机肥替代化肥能显著提高糯玉米鲜穗中可溶性糖含量和粗脂肪含量,F2和F3处理较F1处理可溶性糖含量和粗脂肪含量分别提高22.9%~28.9%和8.5%~11.4%;F2处理较F1处理粗蛋白含量显著提高10.3%;此外,各有机肥替代化肥处理较F1处理的鲜味氨基酸和甜味氨基酸增幅分别为15.7%~19.3%和12.2%~17.4%,其中,F2处理下芳香氨基酸含量较F1显著提高13.0%。综上,等氮量有机肥替代25%和50%的化肥在提高糯玉米鲜穗产量的同时,能显著改善营养品质,实现糯玉米的高产优质,可作为绿洲灌区合理的有机无机肥配施方法。

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。

Protein-Repairing Methionine Sulfoxide Reductases in Photosynthetic Organisms： Gene Organization, Reduction Mechanisms, and Physiological Roles

Methionine oxidation to methionine sulfoxide （MetSO） is reversed by two types of methionine sulfoxide reducrases （MSRs）, A and B, specific to the S- and R-diastereomers of MetSO, respectively. MSR genes are found in most organisms from bacteria to human. In the current review, we first compare the organization of the MSR gene families in photosynthetic organisms from cyanobacteria to higher plants. The analysis reveals that MSRs constitute complex families in higher plants, bryophytes, and algae compared to cyanobacteria and all non-photosynthetic organisms. We also perform a classification, based on gene number and structure, position of redox-active cysteines and predicted sub-cellular localization. The various catalytic mechanisms and potential physiological electron donors involved in the regeneration of MSR activity are then de- scribed. Data available from higher plants reveal that MSRs fulfill an essential physiological function during environmental constraints through a role in protein repair and in protection against oxidative damage. Taking into consideration the ex- pression patterns of MSR genes in plants and the known roles of these genes in non-photosynthetic cells, other functions of MSRs are discussed during specific developmental stages and ageing in photosynthetic organisms.

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。

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。

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。

麦类作物穗器官的光合性能研究进展

由于麦类作物穗器官的光合作用在整株物质生产中占有重要位置,对籽粒产量具有重要贡献,因此应当充分认识当前小麦高产和超高产探索中,穗茎非叶器官的光合优质。穗光合表现出明显的C4型或者C3～C4中间型特征,能够将籽粒呼吸释放的CO2重新固定,对干旱高温的忍耐性明显强于叶片。本文从穗光合对籽粒产量的贡献、穗光合组织结构和光合特性等方面综述了麦类作物穗器官光合性能的研究进展,并提出在小麦超高产实践中发挥非叶器官光合优势的观点。

不同粒叶比小麦品种非叶片光合器官光合特性的研究

通过测定两个不同粒叶比小麦品种Lu 2 2和Lu 14叶片和非叶片光合器官叶绿素含量、光合速率及叶绿素荧光参数 ,探讨了非叶光合器官光合特性的差异。结果表明 ,高粒叶比品种Lu 2 2各部位的叶绿素含量均高于低粒叶比品种Lu 14 ,特别是在衰老后期 ,Lu 2 2能维持较高的叶绿素含量 ;在叶片叶绿素含量及光合速率明显下降时 ,非叶片光合器官仍能维持较高的叶绿素含量及光合能力 ,这有利于籽粒增重。花后初期 ,品种之间及其不同部位的Fv Fm 差异很小 ,但在衰老后期低粒叶比品种的Fv Fm 下降幅度明显大于高粒叶比品种 ,说明高粒叶比品种Lu 2 2能维持较高的光能吸收转化效率。高粒叶比品种的叶片及穗部PSⅡ天线所吸收的光能向光化学反应分配的能量比例较高 ,随着衰老进程 ,过剩光能增多 ,非叶部位尤其是穗部对过剩光能耗散能力较强。高粒叶比小麦品种的光合功能期较长 ,能以较小的叶面积维持较大的库容 。

不同有机肥对肥城桃果实产量及品质的影响

为了探讨不同有机肥(牛粪、鸡粪、羊粪、猪粪、混粪)对肥城桃果实产量和品质的影响,为肥城桃的高产优质提供理论依据,通过连续3年处理,研究不同有机肥对白里肥城桃果实产量及品质的影响。结果表明,施用有机肥后,果实单果重与对照相比差异均不显著,但产量均显著提高。各有机肥处理都不同程度地提高了叶片的叶绿素a、叶绿素b、叶绿素a+b及类胡萝卜素含量。所有处理的叶片净光合速率(Pn)日变化趋势均呈高—低—高—低的双峰曲线,峰值均在11:30和15:30时出现;其中11:30时为大峰,此时混粪处理的峰值最大,为21.5μmol/(m2·s),15:30时为小峰,其中鸡粪处理的峰值最大,为18.6μmol/(m2·s),对照的这两个峰值均低于各有机肥处理。鸡粪处理的果实硬度与对照相比显著提高;有机肥处理提高了果实的可溶性固形物(TSS)、固酸比(TSS/TA)和维生素C(Vc)含量;除猪粪处理外,其它处理的TSS含量与对照相比显著提高;羊粪、猪粪和混粪处理的TSS/TA值比对照分别提高了17.40%、7.14%和15.60%,差异显著;施入有机肥不但增加了香气的种类,还提高了香气物质的相对含量;各有机肥处理的C6醛类和醇类等青香型化合物的相对总量都低于对照,而果香型酯类和甜香型内酯类化合物的相对含量都高于对照,推测施入有机肥后,果实香气有由青香型转向果香型和甜香型的趋势。另外,还发现了肥城桃果实的特征香气成分,如酯类中的乙酸乙酯、乙酸丙酯、甲酸甲酯、乙酸己酯和丙酸甲酯,醇类中的(E)-2-己烯-1-醇、(Z)-2-己烯-1-醇和(Z)-4-己烯-1-醇等C6醇,醛类中的(E)-2-己烯醛、2,4-己二烯醛等C6醛,还有苯甲醛。综合以上结果,施入各种有机肥均能提高果实的营养和香气品质,因此在生产中非常值得大力推广。