Die Entwicklung und der Zn−, Fe− und P-Gehalt höherer Pflanzen in Abhängigkeit vom Zinkangebot

The growth and Zn-, Fe- and P-contents of higher plants in relation to Zn-supply The influence of varied supply of zinc was studied on nine different plant species growing in water culture under controlled experimental conditions. The results of the trials were as follows: 1. The vegetative development of the plant was enhanced by increasing supply of zinc in the nutrient solution. Visible symptoms of zinc deficiency were observed in all plants tested up to a level of 10 μg Zn/l in the nutrient medium. Latent zinc deficiency is to be expected when the zinc supply lies between 10 and 100 μg/l. Normal plant development was recorded in the 100 μg/l Zn/l treatment. 2. The zinc content of all plant organs (except in the trial series without zinc) rose with increasing zinc supply. Zinc contents differed greatly depending on plant species. In onions deficiency symptoms appeared during plant development at a zinc content below 7.8 ppm in the dry matter of the leaves. The corresponding value for flax was 21.5 ppm Zn. The range of latent zinc deficiency was characterized by zinc contents between 13.8 and 37.5 PPm. The optimal zinc content differs depending on plant species. For these very varied Zn-treatments and different species, values between 15.8 and 52.0 were found. 3. Leaf Zn content does not always provide a reliable measure of the Zn-nutritional status of the plant. This is, because zinc contents are extremely dependent upon plant species, the age of the plant, and experimental conditions, etc. 4. A higher zinc concentration was measured in older than in younger leaves. 5. The phosphorus contents in all organs were depressed by increasing zinc supply in the nutrient solution. The leaves of the plants in the trial series without zinc had the heighest phosphorus content. The P:Zn ratio at optimal plant growth differs between species. In the control plants this ratio, measured in the younger leaves, was 100 in millet and 262 in soybean. When the symptoms of zinc deficiency are very pronounced, these values lie above 1000. Zinc deficiency does not occur if the P:Zn ratio is below 250 (except in Cotton and beans). 6. Increasing zinc supply led to a decrease in the iron content in the plant organs of all species tested. The iron content was particularly high in those plants which did not receive any zinc.     

Influence of zinc on the growth,distribution of elements,and metabolism of one‐year old American ginseng plants

Using a water culture technique, 0.05 ppm zinc (Zn) was found to be the critical deficiency concentraction for one‐year American ginseng (Panax quinquefolium L) plants, 0.3 ppm was optimum, 0.5 ppm the critical Zn‐toxicity concentration, and 10 ppm the concentration when severe toxicity occurs. Therefore, the optimum Zn concentration for the growth of American ginseng plants was between 0.1 ppm ‐ 0.3 ppm. Zinc deficiency symptoms of one‐year old American ginseng plants were indicated by the inhabition of root growth, with little fibrous root development, and smaller leaves compared to normal leaves. The symptoms of toxicity were also indicated by the inhibition of root growth, and when seedlings were suffering from an acute toxicity, no fibrous roots appeared, and eventually the roots yellowed and leaves grew slowly or even entirely ceased to grow, the final result being very small leaves which are also chlorotic. Zinc maintained within the 0.1 ppm to 0.3 ppm sufficiency range promoted the synthesis and accumulation of ginsenosides by American ginseng plants, and both low and high Zn concentrations restrained the synthesis and accumulation of ginsenosides. Both Zn deficiency and the optimum Zn concentration (0.3ppm) are beneficial to the accumulation of amino acids in the roots of American ginseng plants. Close to the optimum Zn concentration, the ratios of P/Zn and Fe/Zn in the shoot of American ginseng plants were maintained at 77 and 9.4, respectively.     

Symptome von Bormangel und Borüberschuß bei Hibiscus esculentus

Boron deficiency and Boron toxicity in Hibiscus esculentus The development of symptoms in Okra under conditions of B-deficiency and B-toxicity was observed. It was compared if the symptoms correspond with the B-contents and the growth of the plants. Symptoms of Boron deficiency in Okra are the same as in the other annual dicotyledons. The first visible microscopical symptom is a disturbance in the cambium region. Characteristic is an enlargement of the cambium. New divided cells do not differentiate. Visual symptoms are breaking of stems and petioles, thickening of these organs, cracking, dying of the tips and falling of buds. With a periodic supply of Boron correlations between Boron content and deficiency symptoms were not found. In the B-toxicity range small yellow chlorosis developed on the margins of the older leaves. These symptoms are not to be used for diagnosis. Boron contents higher than 72 μg B/g DM gave a better measure for B-toxicity. Growth and development of symptoms were in agreement with the high Boron contents.     

Micro nutrient uptake of glasshouse cucumbers grown on rockwool

Abstract

The uptake of micro elements by cucumbers grown on rockwool was investigated in a series of experiments. The elements studied in the experiments consisted of iron, manganese, zinc, boron, copper and molybdenum. Five different levels of each of these elements were compared.

The deficiency and excess symptoms were described and the fruit yields were recorded. The trace element contents of the nutrient solution in the root environment were determined by regular sampling. From time to time, samples were also collected of the leaves and fruits of the cucumber crop.

No relationship appeared to exist between the iron contents in the root environment and those in the leaves and fruits. However, relationships were found for all other elements included in the investigation. The relationship between the contents in the root environment and in the crop is curvilinear and can be compute roughly by a function of the model y = ax^b, in which x represents the content of the element in the root environment and y represents the content in the crop.

The limits are given at which deficiency and excess symptoms may be expected.     

Physiologische Voraussetzungen für die Bildung der Kupfermangelsymptome

Physiological conditions for the development of copper deficiency symptoms So as to be able to follow the appearance of copper deficiency symptoms, investigations were initiated to study the time of lignification, transpiration, guard cell mechanism and the growth of epidermis cells. Summarising, it was ascertained that: 1) The cause of all typical copper deficiency symptoms, rolling up of the leaves, followed by wilting and death, lies in retarded lignification and incomplete formation of the vascular structure. 2) Damaged guard cells must be seen as a late occurring subsequent symptom. This damage appears after the onset of the visible symptoms and still longer after the delay in lignification. 3) No relation could be found between the wilting symptoms and the development of epidermis cells.     

Morphology and physiology of zinc‐stressed mulberry plants

The aim of this study was to induce symptoms of zinc deficiency and Zn excess and to relate the generation of reactive oxygen species (ROS) and the altered cellular redox environment to the effects of Zn stress in mulberry (Morus alba L.) cv. Kanva‐2 plants. The antioxidative responses of Zn‐stressed mulberry plants were studied by determining malondialdehyde content (MDA, a measure of lipid peroxidation) as indicator of oxidative damage and the ratio of dehydroascorbate (DHA) to ascorbic acid (AsA) as an index of the cellular redox state. The Zn‐deficiency effects appeared as faint paling and upward cupping of the young emerging leaves. The paling intensified with time, and affected leaves finally developed necrotic spots. At advanced stage of Zn deficiency, newly emerged leaves were spindle‐shaped, pale, and small in size. Apart from their stunted appearance, the plants supplied excess Zn did not show any specific visible symptom. Leaf water status of mulberry plant was affected in Zn‐stressed plants. Deficient leaves had decreased water potential (Ψ) and specific water content (SWC), contained less tissue Zn, less chloroplastic pigments, and high tissue Fe and Mn concentrations. However, excess supply of Zn was found to increase Ψ and decrease tissue Fe. Both hydrogen peroxide and MDA accumulated in leaves of Zn‐stressed plants. While the concentration of DHA did not vary in Zn‐deficient leaves, it was increased in leaves of plants supplied excess Zn. The ratio of the redox couple (DHA to AsA) was increased both in Zn‐deficient or Zn‐excess plants. The activities of superoxide dismutase (EC 1.15.1.1), catalase (EC 1.11.1.6), peroxidase (EC 1.11.1.7), and ascorbate peroxidase (EC 1.11.1.11) increased in Zn‐stressed plants. The results suggest that deficiency or excess of Zn aggravates oxidative stress through enhanced generation of ROS and a disturbed redox homeostasis in mulberry plants.     

Diagnosis of zinc deficiency in cotton

The diagnosis of Zn deficiency in cotton by means of total analysis or the appearance of deficiency symptoms is unsatisfactory. In order to obtain a better understanding of the development of Zn deficiency symptoms in relation to Zn content cotton plants were cultivated in waterculture under reproducible environmental conditions and Zn deficiency induced by different means. It was observed that deficiency symptoms developed equally, regardless of the inducing factors such as low Zn in the nutrient solution, high nutrient solution pH, high Ca and high Fe supply. High amounts of P in the nutrient solution did not induce Zn deficiency symptoms. Zn deficiency symptoms appeared first as interveinal chlorosis in the medium-aged leaves. The internodes remained short. Later red spots appeared on the leaf blades. The leaves suffering from deficiency were thicker because of enlarged palisade cells. The total Zn content of the leaves did not correlate with the symptoms. Different fractions of the Zn in the leaf (extractable with water, NaCl solution, hydrochloric acid) gave no better results. The analytically determined and calculated Zn fractions are discussed in relation to Zn deficiency inducing conditions.     

Effect of zinc application on the dry matter yield uptake and distribution of zinc and other micronutrients in cocoa (Theobroma cacao. L.)

Abstract

The effects of application of zinc fertilizer on dry matter yield, uptake and distribution of zinc and other nutrients by Amazon and Amelonado cocoa cultivars grown in a soil of low zinc content in the greenhouse were investigated.

There was a differential response to zinc fertilization by the two cocoa cultivars. Maximum dry matter yields of Amazon and Amelonado were attained with 10 ppm Zn and 50 ppm Zn, respectively. Under similar experimental conditions Amelonado seedlings expressed zinc deficiency symptoms whereas Amazon did not.

Zinc concentrations in the leaves, stem and roots of both cuitivars did not give a good index of the zinc status of the crops. This was because of the existence of the “Piper‐Steenbjerg”; effect in that nil zinc rates often gave higher leaf concentration of the zinc than next higher rate. In general, the relative content of zinc followed the pattern; leaves > roots > stem with the Amazon cultivar containing more zinc than the Amelonado.

The distribution of absorbed Cu in the leaves, stem and roots did not differ in both varieties. Whereas Fe uptake was mostly concentrated in the roots, Mn absorbed was largely concentrated in the leaves of both varieties and only Mn uptake in the leaves of Amazon consistently increased with Zn application.

The differences in the uptake and distribution of nutrients between the two cocoa cultivars was attributed to differences in their ability to extract nutrients from the soil and in their requirements for metabolic processes.     

Iron deficiency and zinc toxicity in soybean grown in nutrient solution with different levels of sulfur

A typical symptom of iron (Fe) deficiency in plants is yellowing or chlorosis of leaves. Heavy metal toxicity, including that of zinc (Zn), is often also expressed by chlorosis and may be called Fe chlorosis. Iron deficiency and Zn toxicity were evaluated in soybean (Glycine max [L.] Merr.) at two levels each of Zn (0.8 and 40 μM), Fe (0 and 20 μM), and sulfur (S) (0.02 and 20 mM). Reduction in dry matter yield and leaf chlorosis were observed in plants grown under the high level of Zn (toxic level), as well as in the absence of Fe. Zinc toxicity, lack of Fe, and the combination of these conditions reduced dry matter yield to the same extent when compared to the yield of the control plants. The symptoms of Zn toxicity were chlorosis in the trifoliate leaves and a lack of change in the orientation of unifoliate leaves when exposed to light. The main symptoms of Fe deficiency were chlorosis in the whole shoot and brown spots and flaccid areas in the leaves. The latter symptom did not appear in plants grown with Fe but under Zn toxicity. It seems that Fe deficiency is a major factor impairing the growth of plants exposed to high levels of Zn. Under Zn toxicity, Fe and Zn translocation from roots to shoots increased as the S supply to the plants was increased.     

Some observations of potassium deficiency in chrysanthemum

Pot chrysanthemums (Chrysanthemum morifolium ‘Bright Golden Anne') were grown at 10 rates of K supply, symptoms of K deficiency were recorded, and the K concentrations in the leaves at harvest were measured. The initial K deficiency symptoms, consisting of glazing and bronzing of the leaf underside, were nearly identical to the injury attributed to the air pollutant, peroxyacetyl nitrate (PAN). Leaves with these symptoms contained 0.5 to 0.6% K. During vegetative growth K deficiency symptoms developed first on the most recently mature leaf; during rapid flower development the symptoms appeared first on the uppermost leaf of the stem. In K‐deficient plants, there was a gradient in K concentration from upper leaves (0.2% K) to lower leaves (1.7% K).     

Einfluß von Kupfer- und Stickstoffmangel auf die Aktivität der Phenoloxidase und den Gehalt an Phenolen in den Blättern der Sonnenblume (Helianthus annuus)

Effect of copper and nitrogen deficiency on phenol oxidase activity and content of phenols in leaves of sunflower (Helianthus annuus) In sunflower leaves of different insertion height the activity of phenol oxidase during the course of the whole vegetation period was determined. In leaves of normal plants this activity reached its maximum during the period of most intensiv growth and decreased continuously with increasing age. The highest activity was found in cotyledons. In normal leaves this maximum decreased with increasing insertion height. Copper deficiency led in cotyledons to a small, in leaves to a severe inhibition of the phenol oxidase activity. Here the decrease of copper content always led to an unproportional decrease of the enzyme activity. After the middle of July, no phenol oxidase activity in leaves of copper deficient plants could be determined. Nitrogen deficiency decreased the yield considerably, while it was lowering the phenol oxidase activity only slightly. Orthodihydroxyphenols, as substrates of phenol oxidase, showed a negative correlation to the enzym activity: The stronger the suppression of the phenol oxidase activity, the higher was the rise of the orthodiphenol content in full expanded leaves. With unsufficient copper supply the plants showed only week deficiency symptoms, although the phenol oxidase activity was completly inhibited. Therefore it is presumed that in sunflower leaves the role of phenol oxidase can partly be taken over by other enzymes.     

Carboanhydrase-Aktivität und extrahierbares Zink als Maßstab für die Zink-Versorgung von Pflanzen

Carboanhydrase activity and extractable zinc as indicator of the zinc supply of plants 1. Maize, millet, tobacco, sugar-beet and vine were grown under controlled environmental conditions with different zinc concentrations in the substrate. Plant growth, zinc and phosphorus content of the dry matter, extractable zinc and carbonic anhydrase activity in the leaves were measured. 2. Increasing supply of zinc to strongly zinc deficient plants resulted in a marked increase of growth, whereas total zinc content of the leaf dry matter was only slightly and carbonic anhydrase activity was strongly affected. In extremely zinc deficient plants carbonic anhydrase activity was close to zero even though the zinc content of the dry matter was higher than 10 μg/g. Therefore carbonic anhydrase activity appears to reflect the amount of physiologically active zinc in the leaf tissue. It seems to be useful to decide critical cases even at latent zinc deficiency. 3. The P/Zn ratio is also an indicator of zinc supply when plants are extremely zinc deficient, but not under latent deficiency. Moreover the P/Zn ratio can vary in a wide range when plants are well supplied with zinc. 4. The zinc concentration of aqueous leaf extracts increased with increasing level of zinc. 2-3 μg Zn/ml extract were found to be sufficient for all plant species used and all conditions of growth applied. Apparently, the Zn-concentration of the aqueous leaf extract is a better parameter of zinc supply than total zinc or carbonic anhydrase activity which, in addition, is much more difficult to determine.     

The effect of Mg: Ca ratio and osmotic potential of nutrient solutions on calcium transport into emergent leaves of the strawberry plant cv. Cambridge favourite

Strawberry plants, cv. Cambridge Favourite were grown at osmotic potentials of ‐0.2 and ‐0.8 bars in nutrient solutions with magnesium : calcium ratios ranging from 0.3 to 5.6: 1. When the OP was ‐0.8 bars, all plants showed leaf tipburn, guttated little, yielded small volumes of exudate overnight from cut stolons and had small calcium concentrations and contents in their emergent leaves, regardless of the Mg: Ca ratio of the nutrient. No symptoms were seen in plants grown at an OP of ‐0.2 bars, although the calcium concentration in the emergent leaves was smaller when the Mg: Ca ratio of the nutrient exceeded 0.8: 1. The overall salt concentration, which reduced the water potential gradient through the root and prevented development of root pressure at night, was more important than the magnesium to calcium balance of the nutrient solution in causing a local calcium deficiency in emergent leaves of the strawberry plant.     

利用螯合–缓冲营养液对小麦苗期磷–锌关系的研究

采用螯合缓冲营养液培养技术（Chelator-buffer culture solution）,对小麦幼苗植株的磷锌营养进行了探讨。结果表明,高磷条件下小麦出现的缺锌黄化与磷中毒症状之间存在着明显区别,本研究结果支持高磷条件下作物出现的黄化是锌缺乏症状而非磷中毒的观点。与缺磷相比,正常供磷促进了小麦的生长,但过量磷对小麦生长有阻碍作用,而且锌的供应加剧了促进或抑制的程度。正常供应磷、锌条件下,小麦幼苗根系或地上部的磷、锌含量、吸收量及转运率均处于相对较高的水平,其余各处理则因为磷或锌供应量不适宜而使植株的磷、锌营养受到不同程度的影响。另外,磷锌相互拮抗的作用方式及大小程度不同:磷主要影响小麦根系对锌的吸收,而锌对小麦磷营养的影响主要是通过对其从根系向地上部转运的抑制来实现的;磷对锌的影响要明显大于锌对磷的影响,磷素水平在小麦的磷、锌营养平衡中起着更为重要的作用。磷锌拮抗作用只在双方供应不适宜的情况下发生,而且相互作用的方式及程度存在明显差异。     

Seasonal Changes of Mineral Nutrients in Fruit and Leaves of ‘Newhall’ and ‘Skagg's Bonanza’ Navel Oranges

In southern Jiangxi province of China, ‘Newhall’(Citrus sinensis Osbeck) navel orange presented a conspicuous symptom of boron (B) deficiency in mature leaves, whereas B deficiency symptoms were not manifested on ‘Skagg's Bonanza’(C. sinensis Osbeck) navel orange. In this study, changes in concentrations of B, calcium (Ca), potassium (K), magnesium (Mg), manganese (Mn), and zinc (Zn) were comparatively investigated in the structural parts of the fruit (rind and pulp) and leaves (old leaves from last season and spring-flush leaves from current year) of ‘Newhall’ and ‘Skagg's Bonanza’ navel orange during the growing season. Two peaks of B concentrations were observed in the rind of the two cultivars during fruitlet growth and fruit enlargement, respectively. Boron concentrations were relatively high in the rind during fruitlet growth, and then decreased in both rind and pulp, whereas, during middle and late fruit enlargement significant increases were found for B in both rind and pulp of the two cultivars. Boron concentrations in old leaves of ‘Newhall’ decreased progressively and remained relatively low, whereas that of ‘Skagg's Bonanza’ was relatively high and changed slightly as the season progresses. Both Ca and K concentrations were above the critical threshold values, while their dynamics were reverse to that of B in fruit and leaves during certain times. Old leaf Mg concentrations of samples at 140 days after full bloom from the two cultivars and spring-flush leaves from ‘Newhall’ were below the threshold limit for sufficiency. In addition, Mg in old leaves was much lower from ‘Newhall’ than from ‘Skagg's Bonanza’. Spring-flush leaf concentrations of Mn and Zn and Mn concentrations in old leaves from ‘Newhall’ were relatively lacking during middle and late season, which accelerated the occurrence of B deficiency symptoms on mature leaves of ‘Newhall.’     

不同水分状况下施锌对玉米生长和锌吸收的影响

选择潮土(砂壤)和土(粘壤)两种质地不同的土壤,进行盆栽试验,研究不同土壤水分条件下施锌对玉米生长和锌吸收的影响。结果表明,施锌显著增加了玉米植株根、茎、叶以及整株干物质重;缺锌条件下玉米植株根冠比、根叶比和根茎比趋向增大。施锌显著提高了玉米植株各器官中锌的浓度和吸收量,并明显促进锌向地上部运移。干旱胁迫抑制了玉米植株生长,根冠比、根茎比、根叶比增大;随着土壤水分供应增加,植株生长加快,各器官生物量以茎和叶增加大于根。水分胁迫下,在潮土上玉米叶片中锌浓度上升;在土上叶片中锌浓度下降。但增施锌后,根和茎锌浓度增加幅度较大,叶片增加幅度较小;施锌和水分胁迫对根和茎锌浓度的交互作用极显著。水分胁迫下,玉米植株对锌的吸收总量减少。水分胁迫和锌肥施用对玉米叶片、茎锌吸收量的交互作用十分显著,但对根锌吸收量的交互影响不显著。     

Differences in shoot growth and zinc concentration of 164 bread wheat genotypes in a zinc‐deficient calcareous soil

Abstract

A greenhouse experiment was carried out to study severity of the zinc (Zn) deficiency symptoms on leaves, shoot dry weight and shoot content and concentration of Zn in 164 winter type bread wheat genotypes (Triticunt aestivum L.) grown in a Zn‐deficient calcareous soil with (+Zn=10 mg Zn kg^?1 soil) and without (‐Zn) Zn supply for 45 days. Tolerance of the genotypes to Zn deficiency was ranked based on the relative shoot growth (Zn efficiency ratio), calculated as the ratio of the shoot dry weight produced under Zn deficiency to that produced under adequate Zn supply. There was a substantial difference in genotypic tolerance to Zn deficiency. Among the 164 genotypes, 108 genotypes had severe visible symptoms of Zn deficiency (whitish‐brown necrotic patches) on leaves, while in 25 genotypes Zn deficiency symptoms were slight or absent, and the remaining genotypes (e.g., 31 genotypes) showed mild deficiency symptoms. Generally, the genotypes with higher tolerance to Zn deficiency originated from Balkan countries and Turkey, while genotypes originating from the breeding programs in the Great Plains of the United States were mostly sensitive to Zn deficiency. Among the 164 wheat genotypes, Zn efficiency ratio varied from 0.33 to 0.77. The differences in tolerance to Zn deficiency were totally independent of shoot Zn concentrations, but showed a close relationship to the total amount (content) of Zn per shoot. The absolute shoot growth of the genotypes under Zn deficiency corresponded very well with the differences in tolerance to Zn deficiency. Under adequate Zn supply, the 10 most Zn‐ inefficient genotypes and the 10 most Zn‐efficient genotypes were very similar in their shoot dry weight. However, under Zn deficiency, shoot dry weight of the Zn‐efficient genotypes was, on average, 1.6‐fold higher compared to the Zn‐inefficient genotypes. The results of this study show large, exploitable genotypic variation for tolerance to Zn deficiency in bread wheat. Based on this data, total amount of Zn per shoot, absolute shoot growth under Zn deficiency, and relative shoot growth can be used as reliable plant parameters for assessing genotypic variation in tolerance to Zn deficiency in bread wheat.     

缺硼对脐橙幼苗硼分配及叶片细胞壁组分硼含量的影响

【目的】 硼在维持细胞壁正常结构方面具有重要的作用,前期结果证实缺硼严重的脐橙叶片细胞壁结构改变程度也更大,但这种变化与细胞壁组分中硼的含量变化是否有关尚不清楚。本研究通过分析缺硼对脐橙幼苗各部分硼分配及叶片细胞壁组分硼含量的影响,明确缺硼症状表现及细胞壁结构变化程度与细胞壁各组分中硼含量变化之间的关系。 【方法】 以纽荷尔脐橙幼苗为试材,利用营养液培养方法进行缺硼处理,测定根、砧木茎、接穗茎、上部叶、下部叶、叶片细胞壁以及细胞壁各组分硼含量的变化情况。 【结果】 缺硼处理9周后上部叶出现叶片卷曲及叶片失绿等症状,而下部叶没有出现任何可见的症状。缺硼处理的脐橙幼苗各部位硼含量和硼吸收量均显著降低,缺硼降低了硼向地上部的相对分配比例且上部叶受到的影响程度更大。在硼正常供应条件下,上部叶和下部叶游离态硼、原生质体硼和细胞壁硼的含量和相对分配比例没有显著差异,说明硼在不同类型脐橙叶片细胞各组分中的分配是相对稳定的。缺硼后水溶性硼 (包括游离态硼和原生质体硼) 在脐橙上部叶和下部叶中都降到极低的水平,尤其是原生质体硼百分含量下部叶甚至是低于上部叶的。缺硼后细胞壁硼占总硼的比例则由22%左右增加到80%以上。与叶片中硼含量的变化趋势一致,缺硼以后虽然上部叶和下部叶细胞壁硼含量都显著降低,但上部叶降低的程度远大于下部叶。进一步分析细胞壁组分硼含量变化,发现缺硼显著降低了上部叶细胞壁中离子结合态果胶硼含量而对下部叶的无明显影响,其他组分硼含量的变化趋势下部叶和上部叶一致。 【结论】 原生质体硼含量的高低并不是决定缺硼症状的主要因素,离子结合态果胶与硼的结合能力对缺硼条件下细胞壁的结构及缺硼症状表现起着至关重要的作用。      

Foliar Symptomology and Tissue Concentrations of Nutrient‐Deficient Vegetative Strawflower Plants

Abstract

Elemental deficiencies of nitrogen, phosphorus, potassium, calcium, magnesium, sulfur, iron, manganese, copper, zinc, or boron (N, P, K, Ca, Mg, S, Fe, Mn, Cu, Zn, or B) were induced in plants of Florabella Pink strawflower [Bracteantha bracteata (Vent.) A. A. Anderberg]. Rooted stem cuttings were planted in 4.87‐L plastic containers and fertilized with a complete modified Hoagland's solution or this solution minus the element that was to be investigated. Plants were harvested for tissue analyses as well as dry weights when initial foliar symptoms were expressed and later under advanced deficiency symptoms. Deficiency symptoms for all treatments were observed within 7 weeks. The most dramatic expression of foliar symptoms occurred with N (chlorotic lower foliage leading to necrotic margins on the mature leaves), Ca (black necrotic spots on the tips of the young leaves), S (uniform chlorosis of young leaves and recently mature leaves), B (thick, leathery, and deformed young leaves), Fe (uniform yellowish‐green chlorosis on the young leaves), and Zn (brownish‐gray necrosis on the tips of the mature leaves). At the initial stage, only Fe‐deficient plants weighed less than the control, whereas K‐, Ca‐, and Mg‐deficient plants had greater dry weights than plants receiving the complete modified Hoagland's solution (control plants). Dry weights of plants treated with solutions not containing N, P, Ca, S, Cu, or Mn were significantly lower when compared with the control plants under an advanced deficiency. Foliar‐tissue concentration data will assist plant‐tissue analysis laboratories in establishing foliar symptom standards for growers.