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1.
不同氮效率玉米杂交种的叶光反射研究   总被引：1，自引：0，他引：1  
培育氮高效的玉米新品种是众多植物育种项目的主要研究领域。反射测量可能用于对作物的氮效率进行快速而经济的评估。本研究以适应低氮的SL (氮高效品种 )和适应高氮的TH (对照品种 )两个玉米杂交种为材料 ,设 0和 1 5 0kgN hm2 两个施氮水平。在播种后 46、62、76、90和 1 0 4d ,用数码相机LEICASIPRO测量玉米叶片的光反射 ,测量结果用L a b 颜色系统进行评估和分析。在这个三维颜色系统中 ,反射参数a 和b 分别描述绿 红和蓝 黄颜色的比例 ,参数L 用来描述颜色的浅淡。结果表明 ,在低氮条件下 ,开花期前后的玉米叶片光反射参数a 和b 在 5 1 0～ 780nm、5 1 6～ 780nm、和 5 4 0～ 780nm 3个特定波段表现出规律性的变化 ,SL 的反射参数a 显著高于TH 的 ,反射参数b 正相反 ,显著低于TH 的b 值。上述结果说明 ,开花期前后的反射测量可以作为玉米氮效率筛选的一个简单、快速而经济的评估工具。  相似文献   

2.
Root exudates play a major role in the mobilization of sparingly soluble nutrients in the rhizosphere. Since the amount and composition of major metabolites in root exudates from one plant species have not yet been systematically compared under different nutrient deficiencies, relations between exudation patterns and the type of nutrient being deficient remain poorly understood. Comparing root exudates from axenically grown maize plants exposed to N, K, P, or Fe deficiency showed a higher release of glutamate, glucose, ribitol, and citrate from Fe‐deficient plants, while P deficiency stimulated the release of γ‐aminobutyric acid and carbohydrates. Potassium‐starved plants released less sugars, in particular glycerol, ribitol, fructose, and maltose, while under N deficiency lower amounts of amino acids were found in root exudates. Principal‐component analysis revealed a clear separation in the variation of the root‐exudate composition between Fe or P deficiency versus N or K deficiency in the first principal component, which explained 46% of the variation in the data. In addition, a negative correlation was found between the amounts of sugars, organic and amino acids released under deficiency of a certain nutrient and the diffusion coefficient of the respective nutrient in soils. We thus hypothesize that the release of dominant root exudates such as sugars, amino acids, and organic acids by roots may reflect an ancient strategy to cope with limiting nutrient supply.  相似文献   

3.
Distribution often elements along the maize leaf and the effect of iron (Fe) deficiency on these distributions were studied using plants grown in nutrient solution. In both the control and Fe‐deficient leaves, the concentrations of Fe, calcium (Ca), magnesium (Mg), manganese (Mn), zinc (Zn), and boron (B) increased and only that of potassium (K) decreased from leaf base to the leaf tip. Nitrogen (N) and copper (Cu) were the only two elements which showed no gradient of concentration along the entire leaf. Iron deficiency decreased the concentration of Fe by the same extent along the entire leaf length. However, it differentially accentuated the uneven distribution of some elements along the leaf length. For example, Fe deficiency increased the concentrations of Cu and N somewhat uniformly along the whole length the leaf; those of P and K were increased only along the lower two‐thirds of the leaves; and those of Ca, Mg, B, Zn, and Mn mostly along the upper one‐half to one‐third of the leaf length. Potassium was the only element whose concentration was lower at leaf tip than at the leaf base under both Fe‐sufficient and Fe‐deficient conditions. My results indicate that the basal half of maize leaf may be a more suitable part for diagnostic purposes since the concentration of most elements is less subject to alteration in this region, especially if a latent or obvious Fe deficiency is present. In view of these observations, the use of the entire maize leaf for diagnostic purposes may have to be reevaluated.  相似文献   

4.
Accelerated soil erosion can impact upon agronomic productivity by reducing topsoil depth (TSD), decreasing plant available water capacity and creating nutrient imbalance in soil and within plant. Research information on soil‐specific cause – effect relationship is needed to develop management strategies for restoring productivity of eroded soils. Therefore, two field experiments were established on Alfisols in central Ohio to quantify erosion‐induced changes in soil properties and assess their effects on corn growth and yield. Experiment 1 involved studying the effects of past erosion on soil properties and corn yield on field runoff plots where soil was severely eroded and comparing it with that on adjacent slightly eroded soil. In addition, soil properties and corn grain yield in runoff plots were compared on side‐slopes with that on toe‐slopes or depositional sites. Experiment 2 involved relating corn growth and yield to topsoil depth on a sloping land. With recommended rates of fertilizer application, corn grain yield did not differ among erosional phases. Fertilizer application masked the adverse effects of erosion on corn yield. Corn grain yield on depositional sites was about 50 per cent more than that on side‐slope position. Corn plants on the side‐slope positions exhibited symptoms of nutrient deficiency, and the ear leaves contained significantly lower concentrations of P and Mg and higher concentrations of Mn and K than those grown on depositional sites. Corn grain yield in experiment 2 was positively correlated with the TSD. Soil in the depositional site contained significantly more sand and silt and less clay than that on the side‐slope position. There were also differences in soil properties among erosional phases. The soil organic carbon (SOC) content was 19\7 g kg−1 in slightly eroded compared with 15\1 g kg−1 in severely eroded sites. Aggregate stability and the mean weight diameter (MWD) were also significantly more in slightly eroded than severely eroded soils. Adverse effects of severe erosion on soil quality were related to reduction in soil water retention, and decrease in soil concentration of N and P, and increase in those of K, Ca and Mg. Severe erosion increased leaf nutrient contents of K, Mn and Fe and decreased those of Ca and Mg. Corn grain yield was positively correlated with aggregation, silt and soil N contents. It was also negatively correlated with leaf content of Fe. Copyright © 2000 John Wiley & Sons, Ltd.  相似文献   

5.
Nutritional deficiencies in Dioscorea esculenta (Lour.) Burk were studied using a novel culture system, applying a constant water table in acid‐washed sand, and a demand‐driven nutrient supply schedule. This system provided a stable growth environment and was highly efficient with respect to resources and labor. Yam plants (cv. Balbal) were propagated from 30 g tuber head setts and grown for 12 or 20 weeks, with nutrients supplied in the water reservoir to meet demand according to weekly leaf counts. Deficiencies of nitrogen, phosphorus, potassium, calcium, magnesium, and sulfur were induced by reducing supply of the relevant nutrient to one tenth of normal. Deficiencies of iron, boron, manganese, zinc, copper, and molybdenum were induced by omitting the relevant nutrient from the culture medium. After 12 weeks, leaf blades of the main stem were sampled from four positions (immature, young expanded, mid, and old) weighed and analyzed for nutrient concentration, and dry weight of plant parts was recorded. Significant growth reduction was achieved for each deficiency except Fe, Zn, Cu, and Mo, which nonetheless developed some foliar symptoms. Effects on nutrient concentrations in leaves are reported, providing concentrations indicative of adequate and deficient status. Dioscorea esculenta was found to be particularly sensitive to Mn deficiency, although symptom presentation was atypical. Unusually low translocation of phloem‐mobile nutrients was also observed, paralleling reported observations on D. alata.  相似文献   

6.
Mineral deficiencies are well-established causal factor(s) for sub-optimum production in citrus. Identifying nutrient constraints based on morphological symptoms or in combination with leaf/soil analysis is often misleading, especially with reference to remediating the nutritional problems of a standing crop. The task becomes further confounded by other co-factors under the conditions favoring the occurrence of multi-nutrient deficiency. Important biochemical markers for various nutrient deficiencies include: ribulose-1,5 biphosphate carboxylase (RuBPCase), nitrate reductase, and glutamate dehydrogenase for nitrogen (N) deficiency; citrate synthetase, aconitase, phosphoenol pyruvate kinase, and glutamic oxaloacetic transminase for phosphorus (P) deficiency; diesterase, acid invertase, arginine decarboxylase, and N-carbamyl putrescine aminohydrolase for potassium (K) deficiency; pyruvate kinase and succinate dehydrogenase for calcium (Ca) deficiency; invertase for magnesium (Mg) deficiency; adolase and aconitase for iron (Fe) deficiency; catalase for manganese (Mn) deficiency (higher peroxidase activity under Mn deficiency is differentiated from Fe deficiency); carbonic anhydrase and nitrate reductase for zinc (Zn) deficiency; and phenylalanine ammonia lyase and nitrate reductase for boron (B) and molybdenum (Mo) deficiency, respectively. These markers have also shown some promise in establishing the physiological basis of tolerance of Satsuma mandarin (Citrus unshiu Marc.) against Mn and aluminum (Al) toxicities involving the Mn-oxidative pathway and complexation of calmodulin protein with Al3+ ions, respectively.  相似文献   

7.
The present investigation aimed to study the leaf mineral composition of sweet cherry trees on different rootstocks, since the literature data on uptake efficiency of different rootstocks is inconsistent. Results confirmed the different uptake efficiency of rootstocks. The efficiency of ‘GiSelA 6’ root is emphasized in uptake and supply of leaves with nitrogen (N), phosphorus (P), potassium (K), zinc (Zn), boron (B), and manganese (Mn), but trees on this rootstock tend to develop calcium (Ca), magnesium (Mg), and copper (Cu) deficiencies. The Prunus mahaleb rootstocks on calcareous sandy soil are efficient supplier of N, P, K, Ca, Mg, Fe, and Cu, but this root tends to develop Zn, B, and Mn deficiencies. Prunus avium seedling as rootstock proved to be less efficient in supply of leaves by N, P, K, Ca, and Cu. Prunus fruticosa ‘Prob’ root showed tendency in developing several leaf nutrient deficiencies. The applied fertilizer program led to low nutrient levels or even deficiency symptoms in leaves.  相似文献   

8.
The leaf nutrient concentrations and the N‐to‐nutrient ratios were analyzed to evaluate the nutritional status of holm oaks (Quercus ilex L.) experiencing various anthropogenic pressures. Leaves (1 year old) of Q. ilex and surface soil (0–5 cm) surrounding the trees were collected at seven natural and seven urban sites in Campania Region (Southern Italy) and analyzed for the concentrations of macro (C, N, P, S) and micronutrients (Mn, K, Na, Cu, Mg, Ca, Fe, Zn). The available soil fraction of micronutrients was also evaluated. The nutrients showed different concentration ranges for the natural and the urban sites in the soil (total and available) and in the leaves, that we reported separately. Organic‐matter content and macronutrient concentrations were higher in the natural soils, while the highest leaf N, S, and P concentrations were found at some urban sites. Concentrations of Cu, Na and Zn both in leaves and soil, and Mg and Fe in leaves from the urban sites appeared to be affected by air depositions. Manganese was the only micronutrient to show higher concentrations at the natural than at the urban sites, both in soil and leaves. For this nutrient, in addition, a relationship between leaf and available soil concentrations was found at the natural sites. The ratios between the concentrations of N and each studied nutrient in the leaves highlighted a different nutritional status between the plants from the natural and urban sites.  相似文献   

9.
The objective of this work was to study the effect of root and foliar application of two commercial products containing amino acids from plant and animal origin on iron (Fe) nutrition of tomato seedlings cultivated in two nutrient media: lime and normal nutrient solutions. In the foliar‐application experiment, each product was sprayed with 0.5 and 0.7 mL L–1 2, 7, 12, and 17 d after transplanting. In the root application experiment, 0.1 and 0.2 mL L–1 of amino acids products were added to the nutrient solutions. In both experiments, untreated control plants were included as well. Foliar and root application of the product containing amino acids from animal origin caused severe plant‐growth depression and nonpositive effects on Fe nutrition were found. In contrast, the application of the product from plant origin stimulated plant growth. Furthermore, significantly enhanced root and leaf FeIII‐chelate reductase activity, chlorophyll concentration, leaf Fe concentration, and FeII : Fe ratio were found in tomato seedlings treated with the product from plant origin, especially when the amino acids were directly applied to the roots. These effects were more evident in plants developed under lime‐induced Fe deficiency. The positive results on Fe uptake may be related to the action of glutamic acid, the most abundant amino acid in the formulation of the product from plant origin.  相似文献   

10.
In Canada, the coniferous forest was generally found to be nitrogen (N) deficient, but base cation deficiencies may be becoming more prevalent. Newly-developed nutritional standards based on leaf nutrient concentrations and compositional nutrient diagnosis (CND) were applied on published data of white spruce nutrition from sites across Canada. Results suggest that nutritional disorders in white spruce are not restricted to N deficiencies. Based on nutrient concentrations, deficiencies are common, particularly in phosphorus (P), potassium (K), and calcium (Ca), but toxicities are rare. The CND analysis revealed some cases of excess N, P, and magnesium (Mg).  相似文献   

11.
Growing Fe-efficient genotype(s) could be considered as a preferred genetic approach to tackle the widespread constraint of Fe-deficiency-/lime-induced chlorosis in crop grown on alkaline soil. This study aimed to investigate morphological and physiological traits linked to expression of Fe deficiency among four corn (Zea mays) including sweet (Z. mays sacchrata cvs. H403 and H404) and grain (Z. mays indentata cvs. H500 and H700) hybrids grown in nutrient solution using two Fe concentrations (5 and 50 µM Fe-ethylenediaminetetraacetic acid (Fe-EDTA)). Significant variation was found among studied hybrids in their tolerance to Fe-deficiency stress. Sweet corn hybrids were more sensitive to Fe deficiency as compared with grain corn hybrids and greater reduction was observed in their shoot dry matter at the 5 µM Fe-EDTA treatment. The greatest decrease in plant height, leaf area, and root and shoot dry matter weight under Fe-deficiency condition was found for H403 hybrid. No significant correlation was found between shoot and root Fe concentration with crop tolerance to Fe deficiency. Furthermore, different response of corn hybrids to Fe deficiency is an important factor, which has to be considered in Fe fertilizer recommendation as well as breeding programs.  相似文献   

12.
To investigate the relationship between rice genotypic variation in tolerance to iron (Fe) toxicity and nutrient element status, 10 rice genotypes with different growing performances under Fe toxicity were grown under normal culture solution and with excessive ferrous (Fe2+)‐Fe concentrations of 250 and 500 mg Fe2+ L‐1. A close relationship was obtained between the relative ratio of symptomatic leaf numbers to total leaf numbers (SLN/TLN) and a relative decrease in dry matter under Fe2+‐toxicity conditions. The genotypic variations in nitrogen (N), phosphorus (P), potassium (K), and magnesium (Mg) uptake were evaluated by the relative decrease in the N, P, K, and Mg content in the plants. Remarkable genotypic variation in tolerance to excessive Fe2+ was observed. The results indicated that excessive Fe2+ reduced N, P, K, and Mg uptake. The nutrient element concentrations, however, were still higher above deficient criteria even in severely affected plants, suggesting that the retardation of growth may not be intirely due to the deficiency of these elements in plants at the seedling stage. Significant correlations were found between the genotypic variation and the decrease in N, P, K, and Mg uptake and in their tolerance to Fe2+ toxicity, which suggests that the ability to maintain higher nutrient element uptake under a Fe2+‐toxic condition contributes the tolerance to Fe2+ toxicity.  相似文献   

13.
【目的】根系是吸收水分和养分的主要器官,对于多年生木本果树的生长发育尤为重要。由于果树根系庞大、 分布错综复杂,对根系构型和空间分布等的研究相对较少。本文利用计算机扫描系统及其图像分析软件观测根系二维形态参数,并用原子吸收法测定植株养分含量,以探索养分亏缺对枳根系形态的影响,以及根系形态变化与植株养分吸收的关系。【方法】本试验在沙培条件下,以柑橘砧木枳(Poncirus trifoliata)实生苗为试材,研究了缺磷、 钾和钙对其根系形态以及植株体内营养元素含量的影响。利用爱普生数码扫描仪（Expression 10000XL 1.0, Epson Inc. Japan）扫描根系,并用WinRhizo Pro (S) v. 2004b软件(Regent Instruments Inc., Canada)分析获取根系总长、 总体积和总表面积等二维形态参数。利用原子吸收光谱仪(SPECTR AA220)测定样品K、 Ca、 Mg、 Fe、 Cu、 Zn等元素含量。【结果】从扫描数据可知,3 种缺素处理对枳幼苗根系形态结构有较大的影响,即在缺素时根系总长、 表面积和体积均显著降低,缺P处理使枳实生苗粗根的根系长度、 表面积、 体积显著降低,但是增加了中等粗根的表面积和体积; 缺K和缺Ca处理的中等粗根根系长度、 表面积和体积均显著低于对照; 3种缺素处理均显著降低了细根和粗根的根系长度、 表面积和体积。不同缺素处理对植株根系和地上部生长的影响也存在差异,缺P对地上部的抑制作用显著强于根系,缺K处理对根系生长的抑制作用较强,缺Ca对根系和地上部生长的抑制作用均较小。缺Ca处理植株体内Zn和Fe浓度均显著增加但Ca浓度降低,缺P时植株体内Ca和地上部Zn浓度增加,而缺K时植株体内Ca、 Zn浓度增加但Fe和K浓度均显著降低。【结论】不同缺素条件下枳实生苗根系形态各异,导致根系对不同养分的吸收能力不同,从而使植株体内K、 Ca、 Zn、 Fe等养分含量发生改变,最终影响整个植株根系和地上部的生长,表现出各缺素环境所特有的树体特征。  相似文献   

14.
The relative amount of phytosiderophore produced by various Strategy II plants has been categorized as follows: barley (Hordeum vulgare L.) > wheat (Triticum aestivum L.) > oat (Avena byzantina C. Koch.) > rye (Secale cereale L.) >> corn (Zea mays L.) >> sorghum (Sorghum bicolor (L.) Moench) > rice (Oryza sativa L.). With the exception of rice, these plants developed under oxidized soil conditions, and the C‐3 species produce more phytosiderophore than C‐4 species under Fe‐deficiency stress. Iron‐efficient Coker 227 oat produced phytosiderophore in response to Fe‐deficiency stress, while Fe‐inefficient TAM 0–312 oat did not. Although Fe‐efficient WF9 corn and Fe‐inefficient ys1 corn differed in their ability to obtain Fe, neither produced sufficient quantities of phytosiderophore to explain these differences. The objectives of this research were to determine: (a) if phytosiderophore production of Fe‐deficiency stressed C‐4 species millet (Panicum miliaceum L.) and corn is low or absent compared to identically stressed C‐3 species oat and barley, and (b) if native, inbred and hybrid corn cultivars differ in ability to produce and utilize phytosiderophores.

Although release of phytosiderophore for Fe‐stressed corn and millet was generally lower than oat, quantity of release was not always related to obtaining Fe and maintaining green plants. Barley maintained high leaf Fe and low chlorosis with a minor release of phytosiderophore. Oat with increased release acted similarly to barley, whereas a relatively high release of phytosiderophore from White maize did not effect Fe uptake or greening. Likewise, small amounts of phytosiderophore were produced by all corn types, but corn was generally unable to obtain adequate Fe from the growth medium. Two of the native corns, Coneso and Tepecintle, maintained relatively low chlorosis, but they differed in phytosiderophore release. Thus, it appears that the C‐4 plants studied herein generally release a lower amount of phytosiderophore than do C‐3 species, but overcoming Fe‐deficiency chlorosis is not guaranteed by such release. The Strategy II mechanism of mere release of phytosiderophore and consequential Fe acquisition appears simplistic. There is a need for understanding what other factors are involved.  相似文献   

15.
The responses of metabolic networks to mineral deficiency are poorly understood. Here, we conducted a detailed, broad‐scale analysis of macronutrient concentrations and metabolic changes in the shoots and roots of cabbage (Brassica rapa L. ssp. pekinensis) plants in response to N, P, K, Ca, and Mg deficiency in nutrient solution. To standardize individual macronutrient‐deficient treatments, the concentrations of the other nutrients were maintained via substitution with other ions. Individual nutrient deficiencies had various effects on the uptake and accumulation of other mineral nutrients. Phosphorus deficiency had relatively little effect on other mineral nutrient levels compared to the other treatments. Cation deficiency had little effect on N and P concentrations but had a somewhat negative effect on the uptake or concentrations of the other nutrients. Primary metabolic pathways, such as energy production and amino acid metabolism, were greatly affected by mineral nutrient deficiency. Compared to the control treatment, soluble sugar levels increased under –N conditions and decreased under –Ca and –Mg conditions. The levels of several organic acids involved in glycolysis and the TCA cycle decreased in response to –N, –P, or –K treatment. The levels of most amino acids decreased under ‐ N treatment but increased under –P, –K, –Ca, or –Mg treatment. Mineral depletion also led to the activation of alternative biochemical pathways resulting in the production of secondary metabolites such as quinate. Notable changes in metabolic pathways under macronutrient deficiency included (1) a quantitative increase in amino acid levels in response to Mg deficiency, likely because the restriction of various pathways led to an increase in protein production and (2) a marked increase in the levels of quinate, a precursor of the shikimate pathway, following cation (K, Ca, and Mg) deficiency. These findings provide new insights into metabolic changes in cabbage in response to mineral deficiency and pave the way for studying the effects of the simultaneous deficiency of more than one macronutrient on this crop.  相似文献   

16.
Some plants respond to Fe‐deficiency stress by inducing Fe‐solubilizing reactions at or near the root surface. In their ability to solubilize Fe, dicotyledonous plants are more effective than monocotyledonous plants. In this study we determined how representative plants differ in their response when subjected to Fe‐deficiency stress in a calcareous soil and in nutrient solutions. Iron‐inefficient genotypes of tomato, soybean, oats, and corn all developed Fe chlorosis when grown in soil, whereas Fe‐efficient genotypes of these same species remained green. The same genotypes were grown in complete nutrient solutions and then transferred to nutrient solutions containing N (as NO3 ‐) and no Fe.

The T3238 FER tomato (Lycopersican esculentum Mill.) Fe‐efficient) was the only genotype that released significant amounts of H from the roots (the pH was lowered to 3.9) and concomitantly released reductants. Under similar conditions, Hawkeye soyhean [Glycine max (L.) Merr.] released reductants but the solution pH was not lowered. Both Fe‐inefficient and Fe‐efficient genotypes of oats (Avena sativa L.) and corn (Zea mays L.) released insufficient H or reductant from their roots to solubilize Fe; as a result, each of these genotypes developed Fe‐deficiency (chlorosis).

The marked differences observed among these genotypes illustrate the genetic variability inherent within many plant species. A given species or genotype may accordingly not be adapted to a particular soil. Conversely, a given species or genotype may be found (or developed) that is precisely suited for a particular soil. In this event, the need for soil amendments may be reduced or eliminated.  相似文献   

17.
Narcissus cv. “Garden Giant” bulbs were grown in N, P, K, Ca, Mg, or Fe-deficient solutions and compared with bulbs grown in the control solution containing all these nutrients. Plants were sampled at 4 stages: (I) at planting, (II) at sprouting, (III) after flower senescence and/or after visible deficiency symptoms developed, and (IV) at lifting. Observation of visible deficiency symptoms showed that leaves of narcissus displayed chlorosis in the —N, —Mg, and —Fe treatments, while roots were most susceptible to Ca-deficient conditions. Root tips in the —Ca treatment showed brown in followed by root rot. In the —N treatment, shoot growth was markedly retarded and leaves were small and yellow. On the other hand, visible deficiency symptoms were not evident in the —P treatment except for early senescence. K deficiency symptoms were also not evident. Narcissus flowers were not affected by the mineral deficiencies and mineral contents in full-bloom flowers were not different between samples.

In the control plants, there was a large accumulation of N in the roots at sprouting and the content decreased thereafter. Large amounts of K accumulated in roots more than in any other organs. On the other hand the Ca content was high in the tunic and Ca in the scales was hardly mobilized thoughout the growth period. A large proportion of each element eventually accumulated in new inner scales whereas only a small fraction in the old outer scales. The -N, -Ca, and -Mg treatments severely depressed dry matter accumulation, unlike the -P, -K, and -Fe treatments. The -N treatment did not affect the concentration of other minerals, but the -P treatment tended to decrease N, K, Ca, and Mg concentrations. On the other hand, the -K treatment increased Ca and Mg concentrations. -Ca caused an increase in Mg concentration and -Mg raised Ca concentration. These results may be due to compensation effects of cation absorption for the maintenance of the cation/anion balance.  相似文献   

18.
Tomato (Solanum lycopersicum Mill. cv. Belladona F1) plants were either self‐rooted, self‐grafted, or grafted onto the commercial rootstocks “Beaufort”, “He‐Man”, and “Resistar” and grown in a recirculating hydroponic system. Three nutrient solutions differing in NaCl‐salinity level (2.5, 5.0, and 7.5 dS m–1, corresponding to 0.3, 22, and 45 mM NaCl) were combined with the five grafting treatments in a two‐factorial (3 × 5) experimental design. At the control NaCl level (0.3 mM), fruit yield was not influenced by any of the grafting treatments. However, at low (22 mM NaCl) and moderate (45 mM NaCl) salinity levels, the nongrafted and the self‐grafted plants gave significantly lower yields than the plants grafted onto He‐Man. The plants grafted onto the other two rootstocks gave higher yields only in comparison with the nongrafted plants, and the differences were significant only at low (Beaufort) or moderate (Resistar) salinity. Yield differences between grafting treatments at low and moderate salinity arose from differences in fruit number per plant, while mean fruit weight was not influenced by grafting or the rootstock. NaCl salinity had no effect on the yield of plants grafted onto He‐Man but restricted the yield in all other grafting treatments due to reduction of the mean fruit weight. With respect to fruit quality, salinity enhanced the titratable acidity, the total soluble solids, and the ascorbic acid concentrations, while grafting and rootstocks had no effect on any quality characteristics. The leaf Na concentrations were significantly lower in plants grafted onto the three commercial rootstocks, while those of Cl were increased by grafting onto He‐Man but not altered by grafting onto Beaufort or Resistar in comparison with self‐grafted or nongrafted plants. Grafting onto the three tested commercial rootstocks significantly reduced the leaf Mg concentrations, resulting in clear Mg‐deficiency symptoms 19 weeks after planting.  相似文献   

19.
Abstract

Significant varietal differences in plant nutrient content have been reported in the literature which would make extremely difficult the interpretation of plant analysis results for diagnosing plant nutritional problems. This investigation was conducted to analyze a relatively large number of uniformly fertilized commercially grown corn (Zea mays) varieties for possible differences in N, P, K, Ca, and Mg concentrations. Whole young plants 60 to 90 cm tall and ear leaves collected at tassel ling were chemically analyzed.

Varietal differences in the concentrations of N, P, K, and Ca in field corn were statistically significant. Varietal differences in Mg concentrations were significant in three out of the six sets of data.

In spite of statistical significance, plant nutrient concentrations were found to be within expected limits for the morphological parts and growth stages examined except for ear leaf P levels in two varieties. These varieties (P.A.G. SX 29 and Pioneer 3304) apparently were capable of accumulating high levels of P, but only when ear leaf P concentrations were generally high for all varieties indicating excessive soil P levels.

The majority of corn varieties tested contained relatively uniform nutrient levels and were not significantly different from one another. The usual bell‐shaped frequency distribution curves indicated normal distributions of plant nutrient contents. Varietal differences in nutrient concentrations were generally not found to be large enough to interfere with interpretation of plant analysis results (except possibly for P accumulation in the two varieties mentioned above). But, there was no indication that critical phosphorus levels were higher in P accumulating varieties than in other varieties.  相似文献   

20.
Abstract

The role of molybdenum in plant growth was examined by growing ‘Emerald’ okra (Abelmoschus esculentus L. Moench) to fruiting in sand‐culture.

Molybdenum treatment lower than 1 ppm, resulted in leaves that were generally pale yellow and curled upwards. At 1 ppm and 4 ppm Mo, plants were generally healthy with deep green leaves, while Mo application at 6 and 16 ppm resulted in stunted plant growth, deep green leaves, and dark brownish coating on the roots. Shoot/root ratio decreased with increasing rates of Mo. Total chlorophyll was unaffected by Mo application, whereas plant dry matter production and fruit yield were depressed at the 16 ppm Mo treatment.

Leaves of plants receiving less than 1 ppm Mo had higher concentrations of NO3‐N, P, K, Ca and Mg than plants receiving above 1 ppm Mo treatments. The reverse was the case with the micronutrient levels. Specifically, Mo treatments higher than 1 ppm increased leaf‐Mo, ‐Fe, Mn and Zn and root‐Mo and Mn. The highest percentage of Fe and Mn, accumulated in the leaves, followed by the root and least in the wood, whereas the roots had the highest percentage of accumulated Mo, Cu and Zn. Leaf‐Mo was positively correlated with leaf‐Fe and Mn and root‐Mo and Mn. Molybdenum deficiency symptoms appeared in plants with leaf‐Mo of 5 ppm and treated with less than 1 ppm Mo. The 2 ppm Mo treatment with leaf‐Mo of 18 ppm produced normal and healthy plants, whereas. Mo application from 8 to 16 ppm with corresponding leaf‐Mo of 42 and 90 ppm Ho respectively produced plants that were severely stunted and had generally poor growth. The relatively high Ho concentration observed suggests that the okra plant is a Mo accumulator.  相似文献   

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