川西高原4种苹果属植物叶片解剖结构与其抗旱性分析

采用常规石蜡制片法和NaOCl法,对川西高原地区4种苹果属植物叶片的解剖结构特征进行了观察,并选取叶片厚度、上下表皮角质层厚度、上下表皮细胞厚度、栅栏组织厚度等14项抗旱性相关指标进行测定,运用方差分析、主成分分析和隶属函数法对4种苹果属植物的抗旱性进行了分析与综合评价。结果显示:(1)4种苹果属植物叶片上下表皮外均附有角质层,表皮细胞排列紧密,上表皮细胞明显大于下表皮细胞,其中变叶海棠的角质层厚度和表皮细胞厚度均较大;气孔均只分布在下表皮,其中花叶海棠的气孔密度最大,花叶海棠和湖北海棠的气孔长、宽最小;栅栏组织由2~3层排列紧密的栅栏细胞组成,海绵组织细胞排列疏松,细胞间隙大,其中山荆子的栅栏组织厚度、栅海比和叶片结构紧密度最大;主脉均为外韧维管束,其中湖北海棠维管束厚度最大,且皮层中有时出现含晶细胞。(2)所选14项指标中除下表皮角质层厚度外,其余13项指标在4个树种间差异显著,经主成分分析筛选出上表皮角质层厚度、下表皮细胞厚度、栅栏组织厚度等8项指标作为4种苹果属植物抗旱性综合评价的代表性指标。(3)隶属函数法分析结果表明,4种苹果属植物抗旱能力大小顺序为:变叶海棠山荆子花叶海棠湖北海棠。     

不同区域长柄扁桃叶片解剖结构及其抗旱性分析

采用常规石蜡切片技术、光学显微镜观察,选取叶片厚度、角质层厚度、主脉厚度、上表皮栅栏组织厚度等10项旱生指标对来自河北丰宁、内蒙古乌审旗和固阳、陕西神木和榆阳共5个地区的长柄扁桃分别在正常生长和干旱胁迫后进行叶片解剖结构分析,探讨其抗旱的解剖结构特征,为长柄扁桃地区间引种和品种选育提供理论依据。结果表明:(1)河北地区长柄扁桃旱害指数最高,旱害最严重,自身耐旱性能最差;神木和固阳地区的旱害指数均低于河北丰宁与乌审旗地区;榆阳区的旱害指数最小,其抵抗干旱能力最强。(2)5个地区的长柄扁桃叶片结构具有相似性,表皮均具有角质层,主脉为双韧维管束,栅栏组织排列紧密整齐,大部分具有上下两层栅栏组织;抗旱性最弱的河北丰宁地区长柄扁桃叶片最大且最薄,上表皮、角质层及叶片紧密度等均最小,栅栏组织细胞只有一层且排列比较疏松,海绵组织细胞排列散乱、不规则且细胞间隙较大,叶脉维管组织口径小,疏导功能微弱;抗旱性最强的榆阳区长柄扁桃的叶片最小且最厚,对应的角质层、上表皮厚度、叶片紧密度等也最大,双层栅栏组织,第一层细胞细长排列紧密,第二层较短,维管组织发达,含较多的贮水细胞(粘液细胞和含晶细胞)。(3)根据5个地区长柄扁桃的旱害指数和叶片解剖结构的各指标参数比较,并通过隶属函数法分析结果表明,各地区长柄扁桃抗旱性顺序为:陕西榆阳区>陕西神木>内蒙古固阳>内蒙古乌审旗>河北丰宁。     

银杏叶发育过程的解剖结构观察

利用半薄切片、扫描电镜和透射电镜技术,对不同发育时期的银杏叶片解剖结构变化进行连续观察.结果显示:(1)展叶期叶片无栅栏组织和海绵组织分化,细胞排列紧密;展叶后叶肉分化为栅栏组织1~2层,细胞呈长椭球形,海绵组织发达,细胞呈横向排列的椭球形,并形成通气系统;衰老期部分海绵组织细胞变小,并纵向排列,通气系统发达.(2)除叶基和叶缘外,成熟叶片的维管束直径基本相同,维管束鞘发达.(3)早期叶片上表皮有较多气孔分布,展叶后气孔密度迅速降低;下表皮气孔数量较多,但气孔密度随叶片的成熟逐渐下降.(4)叶绿体类囊体在展叶期结构简单,常含1~2个较大淀粉粒;生长期类囊体结构逐渐完善,淀粉粒较少,无嗜锇滴;衰老期类囊体瓦解,嗜锇滴大量累积.     

越冬期遮阴条件下3个不同秋眠型紫花苜蓿品种叶片解剖结构与其光生态适应性

在我国南北气候过渡地区, 采用遮阴试验和石蜡切片法, 研究越冬期不同光强对3个不同秋眠型紫花苜蓿(Medicago sativa)品种(‘维多利亚’、 ‘巨人201’和‘游客’)叶片解剖结构的影响。结果表明: 随着光强减弱, 各紫花苜蓿品种表皮结构中上、下表皮角质层厚度, 气孔密度和气孔开度明显下降; 上、下表皮厚度呈上升趋势。随着遮阴强度增加, 叶肉组织中海绵组织细胞宽度显著上升, 栅栏组织厚度、栅栏组织细胞层数、栅栏组织厚度/海绵组织厚度显著下降; 品种间海绵组织厚度和栅栏组织细胞宽度变化趋势不一致。叶片结构整体特征中叶片厚度、叶肉厚度、中脉厚度、组织结构紧密度随光强减弱而显著下降, 组织结构疏松度明显上升, 叶脉突起度变化不明显。品种间各叶片解剖性状变幅及可塑性指数具有明显的差异, 表明其对弱光适应方式不同。Pearson相关分析表明, 各紫花苜蓿品种叶片气孔密度、栅栏组织厚度、叶肉厚度、叶片厚度及栅栏组织厚度/海绵组织厚度与光强呈显著正相关, 可能是紫花苜蓿叶片解剖结构光强敏感特征参数, 其中, ‘维多利亚’叶片敏感特征参数与光强相关程度较低, 与光强相关的性状较少。综合各项分析结果, 初步确定越冬期紫花苜蓿耐阴性与其秋眠性相关, 半秋眠型品种‘维多利亚’ >秋眠型品种‘巨人201’≥非秋眠型品种‘游客’。     

太湖不同污染区域荇菜叶的比较解剖研究

观察了太湖3个不同污染区域内荇菜[Nymphoides peltatum (Gmel.) O.Kuntze]叶的形态和结构.结果表明:污染重的贡湖地区荇菜叶片的栅栏组织和海绵组织基本不分化,薄壁细胞发达,细胞间隙小;苏州东太湖和西太湖2个污染较轻的采集点,荇菜叶片的叶肉栅栏组织和海绵组织明显分化,细胞间隙组织发达;3个地点叶片的维管组织逐渐退化.测量数据的统计分析表明:贡湖地区荇菜叶的叶片厚度、栅栏组织厚度和海绵组织厚度等解剖参数与其他2个样点差异显著.而苏州东太湖与西太湖两个区域叶片解剖参数之间,除海绵组织厚度和下表皮厚度有差异外,其他参数无明显差异.     

延安城区10种阔叶园林植物叶片结构及其抗旱性评价

利用石蜡切片法和指甲油印迹法,对延安城区10种阔叶园林植物叶片解剖结构——叶片厚度、上下表皮角质层厚度、上下表皮厚度、栅栏组织厚度、海绵组织厚度、中脉厚度、维管束厚度、下表皮气孔密度、气孔长度、气孔宽度等进行测定,对栅栏组织与海绵组织厚度比、叶片结构紧实度、维管束厚度与叶脉厚度比等15个植物抗旱性指标进行分析,并运用方差分析和主成分分析,结合抗旱隶属函数法对物种间的抗旱性进行综合评价。结果表明:(1)15个旱性指标在10种阔叶园林植物间差异显著,变异系数为19.34%～73.73%,均具有较高灵敏度。(2)10种植物叶片均具备抵抗干旱环境的解剖结构,表皮、角质层、栅栏组织、叶脉、维管束等较为发达,气孔主要分布在下表皮,国槐为等面叶,其余为异面叶。(3)叶片上下表皮厚度、栅栏组织厚度、维管束厚度、气孔密度可作为园林植物抗旱性综合评价的主要指标,10种阔叶园林植物的抗旱性大小顺序为:樱花>月季>红叶李>国槐>紫丁香>紫藤>爬山虎>丝绵木>连翘>紫叶小檗。     

马蔺叶片解剖结构特征与其抗旱性关系研究

通过温室模拟干旱胁迫试验,从中国北方不同生境生长的15份野生马蔺种质材料鉴定出3个不同抗旱性群体(强抗旱、中度抗旱和弱抗旱),从中选择具代表性的不同抗旱级别的4份马蔺种质,进行其叶片组织解剖结构特征的观察和比较,以进一步证实马蔺叶片解剖结构特征及其与抗旱性的关系。结果表明,各种质材料间叶片厚度、上下表皮细胞厚度、角质层厚度、气孔密度、栅栏组织厚度、海绵组织厚度、栅栏组织/海绵组织厚度、CTR值和SR值等结构参数指标均与马蔺种质材料抗旱性存在密切的关系。其中,强抗旱种质材料的叶片厚度、上下表皮细胞厚度和角质层厚度大,气孔密度大,栅栏组织和海绵组织较发达,叶片组织紧密度大、疏松度小,栅栏组织/海绵组织厚度比较高;弱抗旱种质材料的叶片厚度、上下表皮细胞厚度和角质层厚度小,气孔密度小,栅栏组织和海绵组织较薄,叶片组织紧密度小、疏松度大,栅栏组织/海绵组织厚度比较低。     

遮荫对金莲花光合特性和叶片解剖特征的影响

以金莲花为材料,系统研究了不同遮荫处理(全光照、40%、60%和80%遮荫)对金莲花叶片光合特性和叶解剖结构的影响,为金莲花引种驯化和抚育管理提供理论依据。结果表明:全光照下金莲花叶净光合速率有明显光合"午休"现象,遮荫处理下"午休"现象不明显。其中,40%遮荫处理显著促进了金莲花叶片净光合速率,80%遮荫处理则起抑制作用;40%和60%遮荫处理促进金莲花叶蒸腾速率和气孔导度的提高,降低了蒸汽压亏缺,有利于光合作用的进行;80%遮荫处理下胞间CO2浓度提高,气孔限制值和蒸汽压亏缺均显著高于其它处理,抑制了金莲花叶蒸腾作用和光合作用;遮荫处理降低了金莲花叶光补偿点和暗呼吸速率,40%和60%遮荫处理下表观量子效率和最大净光合速率提高,说明金莲花有一定耐荫性;金莲花叶光合特性与解剖结构关系密切。遮荫降低了金莲花叶气孔密度和气孔指数,但气孔纵轴长和横轴长显著高于对照。40%和60%遮荫处理下,单叶气孔数量没有明显变化;遮荫下金莲花叶片增厚。栅栏组织厚度和细胞层数减少,栅栏细胞宽度加大,且第二层栅栏细胞有向海绵组织过度的趋势。海绵组织厚度增加,栅栏组织/海绵组织比值减小。随遮荫度增高,栅栏组织和海绵组织细胞间隙增大。该结构有利于提高对光能的利用效率;遮荫处理促进维管束的发育,维管束数量增加,木质部、韧皮部分化明显,其中中脉导管直径和导管数目增加,有利于蒸腾作用和光合作用的进行。     

柠条锦鸡儿小叶解剖结构的环境分异性研究

以巴丹吉林、腾格里、乌兰布和及库布齐沙漠的柠条锦鸡儿成熟叶片为研究对象,采用石蜡切片法,观察叶的横切结构,使用Motic Images Plus 2测定叶片厚度、栅栏组织细胞长和上、下表皮厚度等指标,分析比较4个沙漠的柠条锦鸡儿小叶解剖结构差异。结果表明:(1)生长环境不同,柠条锦鸡儿小叶在表皮、叶肉和叶脉结构上都存在差异,以巴丹吉林沙漠与库布齐沙漠的差异性最为显著。(2)干旱环境下,叶片变小、变厚,栅栏组织和维管束组织更为发达,巴丹吉林沙漠最为干旱,叶片最厚,栅栏组织细胞层数最多、细胞最长,导管列数最多;库布齐沙漠水分条件最好,叶片最薄,栅栏组织细胞最短且层数最少,导管列数最少。(3)对柠条锦鸡儿小叶解剖结构的各项指标与环境参数进行相关分析发现,温度和降水是影响柠条锦鸡儿小叶解剖结构变化的主要因素。     

宁夏10种观赏灌木叶片解剖结构及其抗旱性综合评价

采用显微制片技术,对宁夏10种主要灌木树种叶片的解剖结构进行了观察,分别测定了叶片厚度、上下角质层厚度、栅栏组织、海绵组织、气孔密度等15个与抗旱性相关的指标,并对15个指标进行主成分分析,用隶属函数法对10种灌木的抗旱性进行了综合评价。结果表明:10种灌木的叶片具有典型的旱生结构,大多数具有表皮毛,且具有明显的角质层结构;上、下表皮细胞及叶肉细胞排列紧密。15个指标在各灌木树种间的差异均极显著,其中叶片厚度、上角质层、栅栏组织厚度、气孔密度和主脉维管束直径为叶片旱性结构的主要因子。通过5个主要因子的综合评价,10种灌木的抗旱性大小顺序依次为:沙冬青>花棒>蒙古莸>金叶莸>互叶醉鱼草>蒙古扁桃>鞑靼忍冬>葱皮忍冬>金花忍冬>台尔曼忍冬。     

珠芽蓼叶片对海拔变化的表型可塑性

采用石蜡制片、扫描电镜和透射电镜方法,研究了祁连山植被垂直分布带海拔2300、3200和3900 m 珠芽蓼叶片组织结构、叶表皮特征和叶绿体超微结构对海拔升高的适应性变化。结果表明: 珠芽蓼为异面叶,随海拔升高,叶片表皮毛数目减少而直径增大变粗,表皮蜡质层结构更加致密。叶片厚度在海拔3200 m最大,分别比海拔2300和3900 m增加了39.6%和50.5%。从海拔2300到3200 m,栅栏组织细胞层数由2层增加为3层且细胞排列紧密,海绵组织细胞间隙逐渐增大;在海拔3900 m处,栅栏组织细胞层数减少至2层且细胞间隙增加,海绵组织细胞间隙减小,表皮细胞厚度增加,但细胞层数在3个海拔间无显著差异。随海拔升高,叶下表皮附属物和气孔下室物质的积累增加,气孔密度增加,张度降低,气孔位置由表皮拱起变为内陷。从海拔2300到3200 m,基粒片层由6～9层增至8～12层;至海拔3900 m,基粒片层降为 2～3层且片层之间变得致密,基粒数目减少且排列方向不规则,叶绿体膨大,被膜部分降解。随海拔升高,叶片部分解剖结构指标之间呈现出明显的协同进化,表现出较大的可塑性。珠芽蓼叶片解剖与超微结构在不同海拔表现出的差异显示,表型可塑性及其对高山异质环境和海拔变化的适应特征,是植物长期适应高山复杂环境的结果。     

Influence of Iron Chlorosis on Pigment and Protein Metabolism in Leaves of Nicotiana tabacum L

Experiments were conducted on Nicotiana tabacum, L. to study the relation in the grana among chlorophylls, carotenoids, and proteins. The effect of iron chlorosis on protein and pigment synthesis was studied at different stages of chlorosis using glycine-U-C¹⁴. Pigments were separated by thin layer chromatography.

Chlorophyll a, chlorophyll b, carotenoid, and protein contents of chloroplasts from chlorotic tissue were less than those of normal tissues. A 25% decrease in protein labeling and a 45% decrease in chlorophyll labeling was noted in deficient tissue compared to normal tissue even before chlorosis was perceptible. Both normal and iron deficient leaf discs which received iron in the incubation medium incorporated higher amounts of radioactive glycine into chlorophyll a and chlorophyll b at all stages of development than their respective counterparts not supplied with iron in the incubation medium. The presence of iron in the incubation medium reduced the amount of glycine incorporated into carotenes and xanthophylls, except where the tissue was severely chlorotic. This may be attributed to active competition for glycine between the iron-dependent- (chlorophyll) and iron-independent-(carotenoid) biosynthetic pathways. Incorporation of glycine into chloroplast pigments was lowest at severe chlorosis, probably due to a reduction in the overall enzyme activity.

     

Leaf structural changes associated with iron deficiency chlorosis in field-grown pear and peach: physiological implications

Plants grown in calcareous, high pH soils develop Fe deficiency chlorosis. While the physiological parameters of Fe-deficient leaves have been often investigated, there is a lack of information regarding structural leaf changes associated with such abiotic stress. Iron-sufficient and Fe-deficient pear and peach leaves have been studied, and differences concerning leaf epidermal and internal structure were found. Iron deficiency caused differences in the aspect of the leaf surface, which appeared less smooth in Fe-deficient than in Fe-sufficient leaves. Iron deficiency reduced the amount of soluble cuticular lipids in peach leaves, whereas it reduced the weight of the abaxial cuticle in pear leaves. In both plant species, epidermal cells were enlarged as compared to healthy leaves, whereas the size of guard cells was reduced. In chlorotic leaves, bundle sheaths were enlarged and appeared disorganized, while the mesophyll was more compacted and less porous than in green leaves. In contrast to healthy leaves, chlorotic leaves of both species showed a significant transient opening of stomata after leaf abscission (Iwanoff effect), which can be ascribed to changes found in epidermal and guard cells. Results indicate that Fe-deficiency may alter the barrier properties of the leaf surface, which can significantly affect leaf water relations, solute permeability and pest and disease resistance.     

Changes in the Biochemical Composition, Structure, and Function of Pea Leaf Chloroplasts in Iron Deficiency and Root Anoxia

A combined effect of iron deficiency and root anoxia on the biochemical composition, function, and structure of pea leaf chloroplasts was studied. It was found that the chlorosis of apical leaves in response to iron deficiency was determined by the reduction of light-harvesting complexes I and II. Under root anoxia, complexes of the reaction centers of photosystems I and II degraded first. Weak activity was preserved even in yellow and white leaves under the effect of both factors. The ultrastructure of leaf chloroplasts gradually degraded. Initially, intergranal thylakoid sites were reduced, and the longitudinal orientation of grana was disturbed. However, yellow and white leaves still retained small thylakoids and grana. It is concluded that the degrading effects of iron deficiency and root anoxia on the complex composition and leaf chloroplast structure and function are additive because of their autonomous mechanisms.     

Changes in the biochemical composition, structure, and function of pea leaf chloroplasts in iron deficiency and root anoxia

A combined effect of iron deficiency and root anoxia on the biochemical composition, function, and structure of pea leaf chloroplasts was studied. It was found that the chlorosis of apical leaves in response to iron deficiency was determined by the reduction of light-harvesting complexes I and II. Under root anoxia, complexes of the reaction centers of photosystems I and II degraded first. Weak activity was preserved even in yellow and white leaves under the effect of both factors. The ultrastructure of leaf chloroplasts gradually degraded. Initially, intergranal thylakoid sites were reduced, and the longitudinal orientation of grana was disturbed. However, yellow and white leaves still retained small thylakoids and grana. It is concluded that the degrading effects of iron deficiency and root anoxia on the complex composition and leaf chloroplast structure and function are additive because of their autonomous mechanisms.     

Cytopathologie von viroid-infiziertem Pflanzengewebe

Cytopathology of viroid-infected plant tissue II. Light- and electron microscopical investigations on the leaf tissue of the Chrysanthemum morifolium cultivar “Mistletoe” after infection with the chrysanthemum stunt viroid (CSV) The infection of the Chrysanthemum morifolium cultivar “Mistletoe” with the chrysanthemum stunt viroid (CSV) leads to the appearance of numerous yellowish leaf spots 2–5 mm in diameter. The cells of these chlorotic leaf areas were investigated by phase contrast- and electron microscopy and compared with the cells of the adjacent green tissue and the tissue of healthy plants. Phase contrast microscopy showed that the chlorotic tissue containes about 50 % more cells per area and that their size is reduced by 30–60 %. The parenchymatic cells of the xylem and phloem are irregular and their walls are malformed. In these cells the chloroplasts are reduced to about half in their size and number. In the electron microscope an accumulation of osmiophilic material between the thylakoid membranes of the chloroplasts of the chlorotic cells and a deterioration of the chloroplast stroma can be observed. Moreover, malformations of the cell wall and in the cell wall-associated plasmalemma-somes are found, which lead to an increase in contrast and to irregularities of their surface and internal structure. The most prominent CSV-specific cytopathic effect in cells of the vascular tissue is the extreme accumulation of microfilament bundles which were analysed in detail with the aid of a goniometer. The observed viroid-induced ultrastructural changes are compared with previously described changes caused by conventional plant viruses and the possible functional implications are discussed.     

Pear plantlets cultured ‘in vitro’ under lime-induced chlorosis display a better adaptive strategy than quince plantlets

In many fruit trees species lime-induced chlorosis causes serious economic damage. In the last few years, the in vitro culture technique has been applied to test rootstocks for susceptibility to iron chlorosis and to study biochemical and molecular aspects of the syndrome. In this study in vitro shoot cultivation of quince rootstocks MA, BA29 and pear cv. ‘Conference’ was used to unravel the relationship between iron deficiency, presence of bicarbonate, and growth development and chloroplast pigment behaviour. Stresses were obtained by using MS medium supplemented with various concentrations of FeNaEDTA and/or KHCO₃. Substrate pH, shoot growth and development parameters, total leaf iron and photosynthetic pigment contents of plantlets were independently determined after 24 days of culture. The medium was acidified by the species under all stress conditions. Iron deficiency and bicarbonate condition led to different growth patterns and modular development among the genotypes. This reflects a different sensitivity and plastic adaptation to the elements of this stress. Iron concentration in leaves and the shoot apex of plantlets decreased in all genotypes. However, chloroplast pigments only decreased in quince plantlets under iron deficiency and bicarbonate condition while they did not change in pear plantlets. Our results demonstrate firstly that a plantlet without a root system, which is cultivated in vitro, is able to sense iron deficiency and bicarbonate enriched conditions and, consequently, activates biochemical and physiological responses. Secondly, acidification appears to be related to iron concentration in tissues of quince rootstocks and pear cultivar. Finally, chloroplast biochemical elements are strongly and differently regulated under both stress conditions and between genotypes.     

烟草叶片衰老期过程中的蛋白质组学分析

大田烟叶生产过程中因打顶打叉的处理,改变了烟叶正常的衰老模式。为研究这一特殊的衰老机制,我们自旺长期开始,对‘云烟87’不同发育阶段烟株的中部叶片,进行形态观测、生理生化分析及蛋白质组学检测。结果显示：随着烟叶的逐渐成熟和衰老,烟草的叶色逐渐变黄,叶片逐渐变短、变窄,厚度减少;解剖结构清晰看到栅栏组织和海绵组织从最初的整齐排列到逐渐排列紊乱,组织细胞间轮廓不明显,细胞间隙明显增大;亚显微观测表明,淀粉粒在叶绿体中逐渐积累,类囊体片层结构被挤散,叶绿体膜被撑破。生理与生化分析表明衰老过程伴随着光合作用速率下降,光合色素降解加速,呼吸代谢的增加,这可能与衰老叶片中叶绿体逐渐崩塌和细胞膜透性增加相一致。iTRAQ标记方法共检测到不同发育阶段432个差异表达蛋白质,其中注释到308个与多种生命过程相关。蛋白差异富集分析表明,烟草叶片衰老过程中与光合作用等合成代谢相关蛋白多下调表达,而逆境反应及呼吸作用等分解代谢相关蛋白多上调表达。     

Effect of Fe 3+, Zn 2+ and Mn 2+ on ferric reducing capacity and regreening process of the peach rootstock Nemaguard (Prunus persica (L.) Batsch)

The peach rootstock Nemaguard is susceptible to lime-induced iron deficiency chlorosis. Under field conditions, application of ferric chelates to the soil is effective in correcting the Fe-deficiency symptoms. The objectives of this work were to study the induction of the root ferric reducing capacity and the relationship between chlorosis and leaf Fe concentration of plants grown hydroponically under different treatments. Results showed that bicarbonate-treated plants grown with a low Fe concentration increased their reducing capacity if they received additional Fe or Zn for a short period (15 h). However, the addition of Mn had no effect. When these Mn-treated plants were changed to nutrient solution with no bicarbonate and sufficient Fe, regreening was retarded several days in relation to the other treatments. In plants grown without bicarbonate, the reducing capacity was higher in plants grown with a low amount of Fe than in plants grown with either 0 Fe or sufficient Fe. In plants grown with bicarbonate and low Fe, the leaves became chlorotic and had low Fe concentration. When these plants received higher Fe supply, the regreening of the old leaves was not complete, though they had even higher Fe concentrations that the new developing leaves which were completely green. Results are discussed in relation to the Fe or Zn requirements of plants to induce reducing capacity and the incapacity of the cells from chlorotic leaves to absorb Fe and repair metabolic and structural damages.     

Diagnosis of iron deficiency in groundnut,Arachis hypogaea L.

Summary Investigations into iron deficiency have been hindered by the lack of a satisfactory diagnostic tissue test, which in turn results from the total iron content of plant tissue commonly being an unreliable index of the iron status. Our measurements of chlorotic and normal leaves of field grown groundnut (Arachis hypogaea L.) showed that total iron was unsatisfactory as the measure of iron status of plant tissue. It was found that iron status was better assessed from an estimate of the ferrous iron content of fresh leaf materials obtained by extraction with o-phenanthroline. Extractable iron content increased with leaf age. Chlorotic buds or the first fully opened leaf always contained less than 6μg extractable-Fe/g fresh tissue. Approved for publication as ICRISAT Journal Article No. 307.