干旱对浑善达克沙地榆叶片解剖结构的影响

采用石蜡切片法对浑善达克沙地流动沙丘顶部、丘间草地处的浑善达克沙地榆及呼和浩特市白榆叶的解剖结构进行了对比观察和分析,以期探讨浑善达克沙地榆在解剖学方面适应干旱的机理。结果表明,虽然属同种植物,但由于环境条件的不同,叶片的解剖结构表现出明显的差异。生境条件最差的流动沙丘顶部的浑善达克沙地榆的抗旱性最强,具体表现为:叶片厚,表皮细胞大,具有较厚的表皮细胞外壁与角质层;栅栏组织发达,细胞缩小,排列紧密。     

遮光对连香树幼苗光合特性及其叶片解剖结构的影响

以2年生连香树实生苗为材料,在田间通过黑色遮阳网设置全光照(L₀)及透光率55%(L₁)、25%(L₂)和10%(L₃)4种光环境,研究遮光对连香树幼苗光合作用及叶片解剖结构的影响。结果表明：(1)连香树幼苗叶片P_n在全光和L₁处理下呈非典型的“乁”形变化,未出现“午休”现象,中午14:00出现极值,而在L₂和L₃处理下变化相对缓和,极值出现在中午12:00;叶片G_s呈现与P_n类似的变化趋势,而C_i则呈基本一致的凹形变化。(2)各处理P_n、G_s和T_r的日均值均表现为L₀＞L₁＞L₂＞L₃,而C_i的日均值则呈相反的顺序;P_n与G_s、T_r、气温和光合有效辐射均呈极显著正相关关系(P＜0.01)。(3)全光照连香树幼苗的光补偿点(LCP)、光饱和点(LSP)、暗呼吸速率(R_d)均显著高于遮光处理,并维持较高的P_n而未出现明显的光抑制;遮光导致幼苗的LCP、LSP、R_d显著降低,有利于充分利用弱光,以满足低光环境下植株的正常生长。(4)与全光照相比,遮光下连香树叶片气孔密度显著变小,但气孔器长度、气孔器宽度、单个气孔器面积显著增加,气孔器面积百分比减少,影响幼苗细胞内外的水分和气体传递。(5)遮光条件下,连香树叶片明显变薄,表皮细胞厚度减小,栅栏组织(PT)厚度降低,排列变得疏松,海绵组织(ST)厚度增加,PT/ST相应减小。(6)与全光照相比,强度遮光下(L₂和L₃)连香树幼苗生长受阻,苗高(H)和基径(D)明显减小,生物量模型D²H下降;而轻度遮光(L₁)下幼苗H和D、H/D和D₂H均未出现显著变化。研究发现,连香树具有一定的光忍耐性和喜光性,对光照条件的生态幅较宽,轻度遮光影响较小,但强度遮光对连香树幼苗气体交换参数和光合响应特征产生了显著影响,同时影响了叶片的解剖结构和气孔分布特征,从而影响连香树幼苗的生长形态。在育苗生产中,适度遮光有利于降低气温、减小蒸腾,但遮光后田间有效辐射强度应保持在自然光强的55%以上。     

不同放牧率对内蒙古典型草原植物叶片解剖结构的影响

以内蒙古草原生态系统定位研究站15a长期放牧样地的7种主要植物(扁蓿豆、冰草、糙隐子草、冷蒿、小叶锦鸡儿、星毛委陵菜、羊草)为材料,通过对不同放牧率(无牧、轻牧、中牧、重牧)下植物叶片解剖结构(角质层厚度、表皮细胞面积、叶肉细胞面积、栅栏/海绵组织厚度、叶片厚度、中脉厚度)特征以及化学成分变化的研究,探讨不同植物对长期放牧的适应策略,从而为典型草原放牧演替规律提供理论依据.结果表明:总体上,植物角质层厚度随放牧率的增加而增加;而表皮细胞面积、叶肉细胞面积、叶片厚度等指标不同植物的反应不同.植物叶片化学成分(全N、全C、纤维素含量、叶绿素a+b及a/b)随放牧率的变化较小.放牧率对冰草、冷蒿、羊草的全C、全N、叶绿素和纤维素含量均没有显著影响(P＞0.05),但却显著降低了糙隐子草的比叶面积及星毛委陵菜和小叶锦鸡儿的叶绿素含量,提高了糙隐子草的纤维素含量及扁蓿豆叶片的全N含量(P<0.05).因此,不同植物对放牧的反应存在着明显的种间差异,其中植物角质层厚度、表皮细胞面积、叶片厚度和中脉厚度是植物对放牧响应最为敏感的指标.     

遮光处理对草珊瑚光合特性及叶片解剖结构的影响

为探索遮光处理对草珊瑚光合特性及叶片解剖结构的影响,为草珊瑚的科学栽培提供理论依据。该研究以2年生草珊瑚为材料,设置全光照(L_0)及50%(L_(50))、70%(L_(70))和90%(L_(90))遮光处理,测定分析其光合特性和叶片解剖结构以及植株生长的变化。结果表明:(1)随着遮光率的增加,草珊瑚叶面光合有效辐射(PAR)、气孔导度(G_s)和蒸腾速率(T_r)逐渐减小,胞间二氧化碳浓度(C_i)先减少后增加,净光合速率(P_n)先增加后减少,并在L_(50)和L_(70)处理下具有较低的PAR、G_s、T_r和C_i,光合‘午休’现象得到有效缓解,表现出更高的P_n。(2)随着遮光率的增加,草珊瑚光补偿点(LCP)逐渐下降,光饱和点(LSP)、暗呼吸速率(R_d)先升高后下降,表观量子效率(AQE)逐渐上升,叶片最大净光合速率(P_(nmax))先升高后下降,并在L_(50)和L_(70)处理下具有较低的LCP,较高的LSP和AQE,以及更高的最大净光合速率。(3)随着遮光率的增加,草珊瑚叶片、表皮细胞、栅栏组织和海绵组织的厚度明显增加,角质层厚度逐渐变薄;在L_(50)和L_(70)处理下,草珊瑚叶片栅栏组织和海绵组织发达,栅栏组织细胞长度变短,海绵组织厚度显著增加,细胞排列疏松,叶绿体数量显著增加;叶肉细胞和叶绿体结构完整,基粒类囊体和基质类囊体片层结构发达,叶片捕获光能力增强。(4)随着遮光率的增加,草珊瑚株高、地径、总叶面积数及单株生物量先增加后减少,并在L_(70)处理下均达到峰值,分别为58.58 cm、5.09 mm、1 038.53 cm~2和15.50 g。研究认为,草珊瑚具有一定的弱光耐受力和光可塑性,50%～70%遮光处理有利于草珊瑚生长,在实际生产中可根据该光照范围选择合适的间套作林分或进行适当的遮光处理。     

缺铁对大豆叶片光合作用和光系统Ⅱ功能的影响

通过气体交换和叶绿素荧光测定研究了缺铁对大豆叶片碳同化和光系统Ⅱ的影响。缺铁条件下大豆光合速率(Pn)大幅下降;最大光化学效率(po)下降幅度较小;荧光诱导动力学曲线发生明显的变化,其中电子传递活性明显下降,K相(VK)相对荧光产量提高。缺铁大豆的天线转化效率(Fv'/Fm')、光化学猝灭系数(qP)和光系统Ⅱ实际光化学效率(ΦPSⅡ)降低,而非光化学猝灭(NPQ)则明显增加。此外,缺铁大豆的光后荧光上升增强。据此,认为铁缺乏伤害了光系统Ⅱ复合物供体侧和受体侧的电子传递;缺铁条件下光系统I环式电子传递的增强可能在维持激发能耗散和ATP供给方面起一定作用。     

赤皮青冈幼苗叶片解剖结构对干旱胁迫的响应

以浙江庆元、湖南洞口和湖南靖州3个种源的赤皮青冈1年生幼苗为材料,采用盆栽称量法控制土壤水分含量,设置土壤相对含水量分别为75%～80%(对照)、55%～60%(轻度干旱胁迫)、45%～50%(中度干旱胁迫)和30%～35%(重度干旱胁迫),研究不同程度干旱胁迫对赤皮青冈幼苗叶片解剖结构和蒸腾作用的影响.结果表明: 干旱胁迫下,3个种源赤皮青冈幼苗叶片的总厚度、上下表皮厚度和栅栏组织厚度均显著降低.栅栏组织厚度与海绵组织厚度比(栅海比)、气孔长度和宽度随干旱程度的增强而显著减小,而气孔密度随干旱胁迫程度的增强而显著增加.干旱处理对叶片主脉厚度无显著影响,木质部厚度的变化因种源而异.叶片结构的变化引起生理功能改变,随着胁迫程度的加强,赤皮青冈幼苗的蒸腾速率显著降低.对照和各干旱处理湖南洞口种源幼苗叶片的下表皮厚度、栅海比、气孔密度显著大于其他2个种源,蒸腾速率显著小于其他2个种源,表明湖南洞口赤皮青冈对干旱胁迫的适应性较强.     

冠层位置对5种阔叶树叶片解剖结构与氮含量的影响

不同树冠位置的叶片为了达到功能的最大化,形成了不同的结构与功能的特征。然而,在相同的环境条件下,不同树种之间叶片对环境的反应是否存在一致规律,我们仍然缺乏了解。本研究采用石蜡切片和化学分析方法,对东北林区5个常见阔叶树种（蒙古栎、白桦、水曲柳、胡桃楸和黄波罗）不同树冠位置叶片的形态（叶厚度）、解剖（气孔密度、保卫细胞长度、栅栏和海绵组织厚度）和氮（N）含量特征进行了研究。结果表明：叶片的特征在种间和种内不同树冠位置均存在明显差异,并存在较强的规律性。在种内,5个树种的叶片和栅栏组织厚度均是上层外部最大,而保卫细胞和海绵组织的变化不明显,N含量的变异与树种有关。叶片所处的树冠高度和暴露程度对叶片的结构与N含量变异有重要影响。树种之间,蒙古栎的气孔密度最大,叶片厚度和海绵组织厚度最小,保卫细胞最短,黄波罗恰恰相反。结果表明,为了更好地执行整个树冠的功能,不同树种叶片均出现了与冠层位置有关的结构特征适应。     

叶片黄化对葡萄生理和果实品质的影响

为了探究叶片黄化对葡萄生理和果实生长的伤害机制,试验以生长在河南省荥阳市蔡寨村表现黄化症状的4年生‘阳光玫瑰’成龄树为试材,通过测定并分析黄化植株与正常植株的茎叶生长量、叶绿素含量、光合特性、叶绿素荧光参数、叶片解剖结构以及果实品质和产量的变化特征,考察叶片黄化后对葡萄生长量、光合指标、叶绿素荧光特性以及果实品质的影响,以期为葡萄开展黄化矫正栽培提供参考依据。研究表明,(1)黄化植株叶片的叶绿素含量、叶片大小、叶片重量、新梢长度、枝条粗度均显著降低;(2)黄化植株叶片的净光合速率(P_n)、蒸腾速率(T_r)、气孔导度(G_s)显著下降,而胞间CO₂浓度(C_i)显著上升;(3)黄化植株叶片的叶绿素荧光参数初始荧光(F_o)、光下最小荧光产量(F_o′)、最大荧光产量(F_m)、相对电子传递速率(ETR)、实际光合量子产量Y(Ⅱ)均比正常植株显著降低;(4)黄化植株叶片厚度、栅栏组织厚度和栅海比比正常植株显著升高,上表皮厚度和...     

盐胁迫下海马齿叶片结构变化

用石蜡切片法制片、光学显微镜观察了海马齿植物营养器官--叶片的盐适应结构变化,以明确盐生植物对盐渍生境适应的叶片结构变化特征,为盐生植物的耐盐机理研究提供依据.结果表明:(1)海马齿植物叶片表现出许多适应干旱和盐渍环境的特点,其基本特征为:叶片肉质化,为典型的等面叶;栅栏组织发达,且含有大量叶绿体;叶表皮气孔微下陷,叶表皮细胞外壁的角质层较薄,表皮细胞大小不等,外切向壁外凸,参差不齐,有些表皮细胞特化为泡状细胞,其数量与盐胁迫的浓度呈正相关.(2)叶的海绵组织中含有大量的薄壁细胞,幼叶海绵组织的薄壁细胞在0.5%～2.5% NaCl胁迫下均变大,且数量也增加;而老叶海绵组织的薄壁细胞只有在低浓度(0.5% NaCl)的盐胁迫下变大,而在高浓度下其薄壁细胞反而变小或成不规则形状.(3)盐晶广泛分布在海马齿的叶肉组织细胞内,且其数量随着盐胁迫浓度增加而增加.     

环境和遗传对烟草叶片结构的影响

叶片性状很大程度上反映了植物的功能及其对环境的适应。叶片性状的变异受环境及遗传特性的影响,但是很多研究未能很好区分出它们的相对影响。本研究通过将同一烟草品种种植于不同地点来认识环境对烟草叶片性状的影响;将不同的烟草品种种植于同一环境来了解遗传差异对烟草叶片性状的影响。研究发现,叶脉密度和叶片厚度受环境的影响较大,气孔密度和长度受环境的影响较小。气孔密度和叶片厚度受遗传的影响较大,叶脉密度和气孔长度受遗传的影响较小。在生长温度高的地方,烟草叶脉密度越大。研究结果对于认识植物对环境的适应性具有重要意义。     

红壤黄花梨叶片黄化症的诊断

通过对福建省建宁县黄花梨"黄化园"及"健园"叶片及土壤的营养诊断,探明了该县近年普遍出现的黄花梨植株叶片黄化现象系植株钙素缺乏所致。分析结果表明,"黄化园"叶片含钙量极显著低于"健园";果园土壤交换态钙含量低及土壤酸性强是引起植株钙素缺乏的主要原因。     

Fe-EDDHA对矫治秦美猕猴桃叶片失绿和营养元素组成的影响

在陕西石灰性土壤秦美猕猴桃果园施用不同剂量叶绿灵 (Fe- EDDHA) ,结果表明 ,萌芽期株施 45 g叶绿灵对矫治秦美猕猴桃叶片失绿黄化效果显著 ,可一直维持到当年落叶。同黄化对照植株相比 ,叶片叶绿素含量增加 1 82 .5 % ,活性铁含量提高 5 3 .2 % ,果实品质得到明显改善。施用叶绿灵还改善了叶片营养元素的含量     

A comparison of ferric-chelate reductase and chlorophyll and growth ratios as indices of selection of quince,pear and olive genotypes under iron deficiency stress

Quince (Cydonia oblonga Mill.), pear (Pyrus communis L.) and olive (Olea europaea L.) genotypes were evaluated for their tolerance to iron deficiency stress by growing young plants in three types of aerated nutrient solutions: (1) with iron, (2) without iron or (3) low in iron and with 10 mM bicarbonate. Plants were obtained either from rooted softwood cuttings or from germination of seeds. The degree of tolerance was evaluated with several indices: (1) the chlorophyll content, (2) the root Fe³⁺ reducing capacity and (3) the whole plant relative growth. Fifteen hours before Fe³⁺ reducing capacity determination, iron was applied to the roots of plants with iron-stress, since this method resulted in increasing the reductase activity. All quince and pear genotypes increased the root Fe³⁺ reducing capacity when grown in the treatments for iron-stress, in relation to control plants of the same genotypes. In olive cultivars, the Fe³⁺ reducing capacity was lower in the iron-stress treatments than in the control one. Studying the relationship between relative growth and chlorophyll content for each genotype under iron-stress, in relation to both indices in control plants, a classification of species and genotypes was established. According to that, most olive cultivars and some pear rootstocks and cultivars appear more iron-efficient than quince rootstocks. Our study shows that in some woody species, determining root Fe³⁺ reducing capacity is not the best method to establish tolerance to iron deficiency stress.     

Effects of branch solid Fe sulphate implants on xylem sap composition in field-grown peach and pear: changes in Fe, organic anions and pH

The effects of placing solid implants containing Fe sulfate in branches of Fe-deficient pear and peach trees on the composition of the xylem sap have been studied. Iron sulfate implants are commercially used in northeastern Spain to control iron chlorosis in fruit trees. Implants increased Fe concentrations and decreased organic acid concentrations in the xylem sap, whereas xylem sap pH was only moderately changed. The citrate to Fe ratios decreased markedly after implants, therefore improving the possibility that Fe could be reduced by the leaf plasma membrane enzyme reductase, known to be inhibited by high citrate/Fe ratios. In peach, the effects of the implants could be observed many months post treatment. In pear, some effects were still observed one year after the implants had taken place. Results obtained indicate that solid Fe sulfate implants were capable of significantly changing the chemical composition of the xylem sap in fruit trees.     

Foliar fertilization to control iron chlorosis in pear (Pyrus communis L.) trees

The effectiveness of foliar fertilization to re-green chlorotic leaves in iron-deficient pear trees has been studied. Trials were made to assess the influence of (i) the level of Fe deficiency, (ii) the leaf surface treated (adaxial or abaxial), and (iii) two different surfactants, L-77 and Mistol. Treatments were ferrous sulphate alone, ascorbic, citric and sulphuric acids, applied either alone or in combination with ferrous sulphate, Fe-DTPA and water as a control. Solutions were applied with a brush and leaves were treated twice each year. None of the treatments caused a full recovery from Fe deficiency chlorosis. Treatments containing Fe caused the largest re-greening effects, and FeSO₄ had a similar re-greening effect to Fe(III)-DTPA. Increases in leaf Chl were more pronounced with abaxial leaf surface applications and in severely deficient leaves. Using Fe(III)-DTPA in foliar sprays does not seem to be justified, since their effects are not better than those of FeSO₄. The joint use of Fe(III)-DTPA and L-77 and that of FeSO₄ and citric acid do not seem to be suitable. With a single foliar application, FeSO₄ combined with acids gave slightly better results than FeSO₄ alone. Acidic solution applications without Fe may be effective in alleviating chlorosis in some cases, especially in the case of citric acid. In the current state of knowledge, foliar fertilization cannot offer yet a good alternative for full control of Fe chlorosis, although its low environmental impact and cost make this technique a good complementary measure to soil Fe-chelate applications and other chlorosis alleviation management techniques. Abbreviations: Chl – chlorophyll; EDDCHA – ethylenediamine di(5-carboxy-2-hydroxyphenylacetic) acid; EDDHA – ethylenediamine di(o-hydroxyphenylacetic) acid; EDDHMA – ethylenediamine di(o-hydroxy-p-methylphenylacetic) acid; EDDHSA – ethylenediamine di(2-hydroxy-5-sulfophenylacetic) acid     

Effects of iron deficiency and iron overload on manganese uptake and deposition in the brain and other organs of the rat

Managanese (Mn) is an essential trace element at low concentrations, but at higher concentrations is neurotoxic. It has several chemical and biochemical properties similar to iron (Fe), and there is evidence of metabolic interaction between the two metals, particularly at the level of absorption from the intestine. The aim of this investigation was to determine whether Mn and Fe interact during the processes involved in uptake from the plasma by the brain and other organs of the rat. Dams were fed control (70 mg Fe/kg), Fe-deficient (5–10 mg Fe/kg), or Fe-loaded (20 g carbonyl Fe/kg) diets, with or without Mn-loaded drinking water (2 g Mn/L), from day 18–19 of pregnancy, and, after weaning the young rats, were continued on the same dietary regimens. Measurements of brain, liver, and kidney Mn and nonheme Fe levels, and the uptake of⁵⁴Mn and⁵⁹Fe from the plasma by these organs and the femurs, were made when the rats were aged 15 and 63 d. Organ nonheme Fe levels were much higher than Mn levels, and in the liver and kidney increased much more with Fe loading than did Mn levels with Mn loading. However, in the brain the increases were greater for Mn. Both Fe depletion and loading led to increased brain Mn concentrations in the 15-d/rats, while Fe loading also had this effect at 63 d. Mn loading did not have significant effects on the nonheme Fe concentrations.⁵⁴Mn, injected as MnCl₂ mixed with serum, was cleared more rapidly from the circulation than was⁵⁹Fe, injected in the form of diferric transferrin. In the 15-d-rats, the uptake of⁵⁴Mn by brain, liver, kidneys, and femurs was increased by Fe loading, but this was not seen in the 63-d rats. Mn supplementation led to increased⁵⁹Fe uptake by the brain, liver, and kidneys of the rats fed the control and Fe-deficient diets, but not in the Fe-loaded rats. It is concluded that Mn and Fe interact during transfer from the plasma to the brain and other organs and that this interaction is synergistic rather than competitive in nature. Hence, excessive intake of Fe plus Mn may accentuate the risk of tissue damage caused by one metal alone, particularly in the brain.     

硫酸亚铁对缺铁性贫血小鼠肠道健康的影响

【目的】旨在探究硫酸亚铁(FeSO4)对缺铁性贫血(iron deficiency anemia, IDA)小鼠肠道健康的影响。【方法】选取45只24日龄体重(16.0±1.2) g的雄性昆明小鼠,随机分成3组,每组15只,即对照组(正常饲料,饮蒸馏水)、IDA组(低铁饲料造模2周,饮去离子水)、IDA-Fe²⁺组(造模结束后灌胃FeSO₄ 3周,饮去离子水),实验结束时采样。【结果】试验结束时,与IDA组相比,IDA-Fe²⁺组小鼠的红细胞、血红蛋白、红细胞压积、平均红细胞体积、平均红细胞血红蛋白量、平均红细胞血红蛋白浓度等贫血指标均恢复至正常水平(P>0.05),表明FeSO4具有改善IDA的功能;与对照组相比,IDA和IDA-Fe²⁺组小鼠的氧化应激指标和肿瘤坏死因子α均显著升高(P<0.01)、紧密连接蛋白Occludin显著降低(P<0.001),IDA-Fe²⁺组与IDA组除结肠总抗氧化能力(TAC)外均无差异显著性(P>0.05)。结肠组织...     

The effects of iron ore dust on mangroves in Western Australia: Lack of evidence for stomatal damage

Anecdotal evidence suggests that iron ore dust derived from industrialshiploading activities in north-western Australia may be more injurious tomangroves than is naturally-derived dust, because of its more angularstructure and presumed ability to damage stomatal cells. Abaxial hairs onthe most common mangrove, Avicennia marina (Forfk). Vierh., havebeen thought to exacerbate this effect through trapping and retaining dust.This study examined this hypothesis. Leaves were collected from dustyindustrial areas and natural environments. Leaves in dusty environmentswere chosen on the basis of their thick coating of iron ore dust on both leafsurfaces. Approximately 3,000 stomata were examined in detail using lightmicroscopy. Hair density, stomatal aperture, cell condition and presence ofdust were also noted. Despite there often being a visible layer of dust onthe abaxial and adaxial surfaces of the leaf, evidence for dust of any kindwithin stomatal spaces was noted, in total, only three times. The lack ofvisible dust in stomata was attributed to three factors; the density andmorphology of the abaxial hairs, which prevent dust from enteringthe space between the hairs, and the improbability of dust circulating in thestagnant air within that space and moving against gravity past the guardcells. It was concluded that if iron ore dust affects mangroves, it must doso by some other mechanism, such as either increased temperature, shadingor a restriction of transpiration by the thickness of the dust on the abaxialsurface.     

The effect of Helicobacter pylori infection and dietary iron deficiency on host iron homeostasis: a study in mice

BACKGROUND: Helicobacter pylori, which requires iron to survive, may cause host iron deficiency by directly competing with the host for available iron or by impairing iron uptake as a consequence of atrophy-associated gastric hypochlorhydria. The aim of this study was to examine the effect of H. pylori infection and dietary iron deficiency on host iron homeostasis in a mouse model. MATERIALS AND METHODS: H. pylori SS1-infected and uninfected C57BL/6 mice, fed either a normal diet or an iron-deficient diet, were assessed for iron status and infection-associated gastritis over a 30-week period. RESULTS: After 10 weeks, serum ferritin values were higher in H. pylori-infected mice than in uninfected controls, irrespective of dietary iron intake (p = .04). The infection-related increase in body iron stores persisted in the iron-replete mice but diminished over time in mice with restricted dietary iron intake (p < .0001). At 30 weeks serum ferritin levels were lower in these animals (p = .063). No significant difference in bacterial numbers was detected at the 30-week time point (p > .05) and the histological changes observed were consistently associated with infection (p < .01) and not with the iron status of the mice (p = .771). CONCLUSIONS: Infection with H. pylori did not cause iron deficiency in iron-replete mice. However, diminished iron stores in mice as a result of limited dietary iron intake were further lowered by concurrent infection, thus indicating that H. pylori competes successfully with the host for available iron.     

Structural and functional integrity of Sulla carnosa photosynthetic apparatus under iron deficiency conditions

• The abundance of calcareous soils makes bicarbonate‐induced iron (Fe) deficiency a major problem for plant growth and crop yield. Therefore, Fe‐efficient plants may constitute a solution for use on calcareous soils.
• We investigated the ability of the forage legume Sulla carnosa (Desf.) to maintain integrity of its photosynthetic apparatus under Fe deficiency conditions. Three treatments were applied: control, direct Fe deficiency and bicarbonate‐induced Fe deficiency.
• At harvest, all organs of deficient plants showed severe growth inhibition, the effect being less pronounced under indirect Fe deficiency. Pigment analysis of fully expanded leaves revealed a reduction in concentrations of chlorophyll a, chlorophyll b and carotenoids under Fe deficiency. Electron transport rate, maximum and effective quantum yield of photosystem II (PSII), photochemical quenching (qP), non‐photochemical quenching (qN) as well as P700 activity also decreased significantly in plants exposed to direct Fe deficiency, while qN was not affected. The effects of indirect Fe deficiency on the same parameters were less pronounced in bicarbonate‐treated plants. The relative abundances of thylakoid proteins related to PSI (PsaA, Lhca1, Lhca2) and PSII (PsbA, Lhcb1) were also more affected under direct than indirect Fe deficiency.
• We conclude that S. carnosa can maintain the integrity of its photosynthetic apparatus under bicarbonate‐induced Fe deficiency, preventing harmful effects to both photosystems under direct Fe deficiency. This suggests a high capacity of this species not only to take up Fe in the presence of bicarbonate (HCO₃^?) but also to preferentially translocate absorbed Fe towards leaves and prevent its inactivation.