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《Journal of plant nutrition》2013,36(10-11):2149-2163
Abstract On calcareous soils, carbonate induced iron deficiency can have heavy effects on growth and development of several fruit crops. Leaf chlorosis, biochemical, and ultrastructural alterations are the first symptoms causing severe damages to yield and productivity. In this work, some physiological, biochemical, and molecular aspects of iron deficiency stress induced on the peach rootstock Mr.S 2/5 in vitro were studied. The aim was to demonstrate if in vitro culture can be used as a valid and fast method to evoke iron deficiency symptoms and to study plant responses to this kind of abiotic stress. Two different treatments were carried out and compared to a control (MS medium): plantlets grown on MS medium completely free of iron and on MS medium containing 1 mM potassium bicarbonate. After 10 and 20 days from the beginning of the treatments fresh and dry weight, chlorophyll, and carotenoids content were measured. Superoxide dismutase and catalase total activity was measured, and gene expression was analyzed by using etherologous probes (Sod1, Sod3, Sod4, and Cat1) obtained from maize. In the absence of iron or in the presence of bicarbonate Mr.S 2/5 plantlets showed a significant decrease in growth, as quantified by fresh and dry weight. The plantlets showed a severe chlorosis due to a reduction in chlorophyll and carotenoids concentration. Iron deficiency stress caused a reduction of the activity of catalase and superoxide dismutase, while inducing an increase in gene expression. 相似文献
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Heidi-Jayne Hawkins Hans Hettasch Jolanta Mesjasz-Przybylowicz Wojciech Przybylowicz Michael D. Cramer 《Scientia Horticulturae》2008,117(4):357-365
South African Proteaceae are adapted to the low soil phosphorus (P) concentrations of the Cape Floristic Region. The efficient P uptake by Proteaceae means that these plants experience phosphorus (P) toxicity at lower rhizosphere [P] than crop plants. This is only problematic when cultivating Proteaceae (and many plants from this region) on previously agricultural land with high residual soil [P]. In this study we hypothesize that P toxicity will result in element imbalances in leaves of Proteaceae and information from this study aims to facilitate ameliorative treatments. Phosphorus toxicity was induced on-farm in Leucadendron ‘Safari Sunset’ (Proteaceae) with subsequent mapping of element distribution in non-necrotic leaf tissue using micro particle-induced X-ray emission spectrometry. Phosphate supply up to 0.01 mM in a fertigation solution resulted in increased stem length of Leucadendron ‘Safari Sunset’ while P concentrations in excess of this resulted in decreased stem length, increased leaf [P] up to 0.25% (w/w) and, between 1 mM and 5 mM P supply, typical P toxicity symptoms were observed. High P supply (5 mM P) resulted in increased leaf [P] in most leaf tissues including the epidermis, where calculations from an equilibrium speciation model indicated that there was 30% more dissolved PO43− in the epidermis compared to leaves at low P supply (0 mM added P on soil with 34 mg P kg−1). Concomitantly, bundle sheath and epidermal [Ca] were reduced and 10% more Ca was predicted to be adsorbed and precipitated as hydrapatite at high P supply. High P supply resulted in increased leaf [Cl] and [Mn] in all tissues studied; decreased total leaf [Fe], bundle sheath, xylem, phloem and epidermal [Fe] and decreased total leaf [Zn] and xylem and phloem [Zn]. The observed symptoms of P toxicity in Leucadendron ‘Safari Sunset’ (necrosis in some plants, chlorosis and leaf rosetting) co-occurred with (1) excess PO43−, which may bind Ca in the epidermis (leading eventually to necrosis); (2) reduced [Fe] and increased [Mn] (leading to chlorosis) and (3) reduced total and vascular [Zn] (leading to leaf rosetting). 相似文献
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The Fe‐inefficient T203 and the Fe‐efficient A7 and Pioneer 1082 (P1082) soybeans (Glycine max (L.) Merr.) were grown hydroponically with no (0 mg Fe L‐1 ; ‐Fe) and a minute level (0.025 mg Fe L‐1 ; +Fe) of Fe to (a) compare their responses to Fe‐deficiency stress and (b) relate Fe‐efficiency in soybeans to their ability to initiate the Fe‐stress‐response mechanism at low levels of Fe. With no Fe in solution, P1082 released similar levels of H+ ions, but released less reductant from their roots and there was less reduction of Fe3+ to Fe2+ by their roots than by A7 roots. These responses were also one day later and occurred after a more severe chlorosis and a lower leaf Fe had developed in P1082 than in A7. With 0.025 mg L‐1 of solution Fe, it was not necessary for the Fe‐stress response mechanism to be fully activated to make Fe available in A7 soybean, whereas a strongly enhanced Fe stress response was observed in P1082. Increased Fe uptake and regreening of leaves immediately succeeded initiation of the Fe stress response in both cultivars and at both levels of Fe. Thus, P1082 was slightly less efficient than A7 soybean, but would be classed more efficient than the previously studied soybean cultivars A2, Hawkeye, Bragg, Pride, Anoka, and T203. These results support the hypothesis that the most efficient soybeans are those which can initiate the Fe‐stress response mechanism with little or no Fe in the growth medium. The near simultaneous occurrence of the factors in the Fe‐stress response mechanism (H ion and reductant release, reduction of Fe to Fe by roots), and the immediate increase in leaf Fe and chorophyll contents following that response suggest that all these factors act in concert, not independently, to aid in the absorption and transport of Fe to plant tops. 相似文献
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The excretion of phytosiderophores by barley (Hordeum vulgare L.) has recently been documented and a major difference in the Fe‐stress response of gramineous species and dicotyledonous species proposed. However, currently used methods of quantifying and measuring phytosiderophore are tedious or require specialized equipment and a cultivar easily accessible to U.S. scientists is needed. The objectives of this study were (a) to determine if “Steptoe”; and “Europa”; (used as a control cultivar) barleys would release Fe3+ solubilizing compounds in response to Fe‐deficiency stress and (b) to develop a technique to determine the efficiency of solubilization of Fe(OH)3 by the released chelating substances. Two cultivars of barley were place under Fe‐stressed (‐Fe) and nonstressed (+Fe) conditions in modified Hoagland solutions (14 L). The solutions were periodically monitored for H+ and reductant release from the roots and plants were rated daily for chlorosis development. Periodic (6 or 7 harvests) evaluation of the release of Fe3+ solubilizing substances was performed as herein described. Neither H+ nor reductant extrusion occurred with either cultivar during Fe stress. However, Fe3+ solubilizing substances were released by both cultivars at relatively high levels under Fe‐stress conditions compared to the nonstressed plants. A convenient technique was developed to measure the release of Fe solubilizing substances released by barley roots. 相似文献
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We investigated for 2 years (1995–1996) the time course development of chlorosis and the variation of iron (Fe) content in vegetative and reproductive organs in two nectarine orchards planted with cv Spring Red and cv Stark Redgold on calcareous soils of the Po valley (Italy) with the final aim to evaluate possible tools for the early prognosis of Fe chlorosis and a more efficient fertilization management. Due to the withdrawal of Fe supply, floral Fe concentration significantly decreased in 1996 as compared with 1995 in cv Spring Red, but not in Stark Redgold. Correlation coefficients between Fe and chlorophyll (Chl) from the same leaves were always higher when Fe was considered as amount present per leaf or per unit of leaf area than as leaf dry weight. The fact that chlorotic and green leaves had similar Fe concentration could be explained by an overestimate of Fe in the chlorotic leaf as a consequence of a reduction of its size. However, the decrease of Chl concentration between 60 and 120 days after full bloom (DAFB) occurred while leaf Fe content generally increased, indicating that even during chlorosis development leaves were supplied with some iron. We therefore suggest that the development of chlorosis was associated with an inactivation of Fe in the leaf apoplast. In 1995, regardless the cultivar, floral Fe concentration and leaf Chl were never correlated. In 1996 floral Fe concentration was linearly related to leaf Chl recorded 60 and 120 DAFB in cv Spring Red only. Floral Fe concentration at full bloom 1996, regardless the variety, was linearly related to leaf Chl determined in spring of the previous year, suggesting that flower Fe concentration might be used for assessing the storage of iron during the previous season. 相似文献
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江苏沿海地区发现桑叶黄化失绿,是一种缺铁为主的缺乏微素综合症。起因于桑园土壤缺乏有效铁,以及土壤中pH值高,并呈HCO_3-离子反应,使铁的有效性降低,致使桑叶活性铁含量下降。另一方面是大量吸收磷素,使植株内磷铁比失调,影响铁的运转,大幅度降低过氧化氢酶和过氧化物酶的活性,影响正常的生理代谢。防治措施:及时喷铁叶面肥、树干注射铁液、增施有机肥料等。 相似文献