Foliar Absorption—an Active Uptake Process

Jyung, W. H.; Wittwer, S. H.

doi:10.1002/j.1537-2197.1964.tb06654.x

Cited by 38 publications

(17 citation statements)

References 22 publications

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“…Ricerche da lui condotte, mediante sostanze nutrienti marcate radioattivamente, hanno permesso, infatti, di ottenere risultati positivi in tal senso in piante colonizzate da endofiti. E' da tempo noto che i nutrienti fogliari, in misura diversa in base al tipo, possano penetrare attraverso la cuticola fogliare della pianta riducendo sintomi di carenza nutritiva (Antal & Joo 1995, Malakondaiah et al 1981, Bukovac & Wittwer 1957, Jyung & Wittwer 1964. Secondo Ragazzi (2004) nelle piante forestali, così come in quelle erbacee, il ruolo dominante degli endofiti sarebbe quello protettivo nei confronti di insetti, funghi e sostanze allelopatiche.…”

Section: Introduzioneunclassified

Fungal endophytes and epiphytes in needles ofPicea abies(L.) Karst. from natural and urban areas in northern Italy

Lorenzi¹,

Lorando²,

Picco³

2006

Forest@

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Fungal endophytes and epiphytes in needles of Picea abies (L.) Karst. from natural and urban areas in northern Italy.The foliar fungal endophytes community inhabiting needles of Picea abies (Norway spruce) has not been well documented. In this study, carried out in Northern Italy, needles were collected in the years 2003 -2004 in Bagni di Masino and Passo S. Marco (natural locations) and in Milano and Pavia (urban areas). Needles were plated and scored for hyphal outgrowth of endophytes to observe composition and distribution pattern. Both colonization percentage and number of taxa were higher in needles collected in natural locations. There was a large difference in the infection levels between natural and urban areas, portion of the needle (the distal portion showing the largest number of colonies) and among the different needle age classes, with the youngest needles being virtually endophytes free and the 5 and 6 age classes being the most colonized. Thus Norway spruce foliar endophytes population appears to be influenced by age and portion of the needle and location. In the year 2003 fungal epiphytes were also investigated to compare the two different populations. Results analisys show a different distribution of endophytic and ephyphitic taxa, some species being mostly isolated in the natural locations others in the urban ones, thus indicating the presence of different clusters. Zythiostroma pinastri and Tiarosporella parca were the most frequent endophytes in natural locations while Sphaeropsis sapinea was common in urban areas. Among the epiphytes Alternaria alternata, Aureobasidium, and Cladosporium were ubiquitous taxa, Phomopsis was mostly isolated in natural locations.

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Section: Introduzioneunclassified

Fungal endophytes and epiphytes in needles ofPicea abies(L.) Karst. from natural and urban areas in northern Italy

Lorenzi¹,

Lorando²,

Picco³

2006

Forest@

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“…However, it was first necessary to prepare leaf tissue in a form suitable for experimental use. The very slow rates of ion uptake found with immersed leaves (Jyung and Wittwer 1964) and isolated leaf cells (Jyung, Wittwer, and Bukovac 1965) suggested that these preparations were unsuitable. As a compromise, leaf disks and slices were studied and, in the course of this investigation, a similar evaluation was published by Smith and Epstein (1964).…”

Section: Introductionmentioning

confidence: 99%

Ion Absorption in Atriplex Leaf Tissue I. Absorption by Mesophyll Cells

Osmond¹

1968

Aust. Jnl. Of Bio. Sci.

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SummaryLeaf tissue cut into disks was unsuitable for quantitative ion-absorption studies because cells in the interior did not equilibrate with the external solution. Ion entry was restricted to the cut surface and diffusion was too slow to permit equilibration of the whole disk (apparent diffusion coefficient for sodium at O· 5°C was 1 X IO-L 3 X 10-7 cm2 sec-I). However, leaf slices 0·5 mm in width permitted rapid access of electrolyte to all cells and were used to study uptake of monovalent cations and oxalate.Cells of mature leaves were near to flux equilibrium for potassium, but not for sodium, and large changes in the ratio of monovalent cations could be induced in single salt solutions. Thus, when leaf slices were placed in N aCI, sodium was taken up largely in exchange for potassium lost from the vacuole; any small net influx of monovalent cation was balanced by chloride absorption. This monovalent exchange uptake was sensitive to low temperature and to carbonyl cyanide m-chlorophenylhydrazone (CCCP). Sodium influx and potassium efflux were reduced by low concentrations of calcium.The kinetics of the uptake of externally supplied oxalate were consistent with its transfer across the tonoplast to a slowly exchangeable compartment. This transfer was reduced by low temperature, which also reduced the concurrent metabolism of oxalate to carbon dioxide, and by CCCP at 25°C, which did not interfere with oxalate metabolism.

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“…The photosynthetic dependence of K+ uptake associated with growth was investigated by measuring the effect of DCMU, an inhibitor of PSII, on accumulation of K+ and uptake of 86Rb+ by leaf discs. The stimulation of K+ and Rb+ uptake by light has been observed in Nitella (28), Vallisneria (39), corn (Zea mays) (40), green bean (Phaseolus vulgaris) (19), pea (Pisum sativum) (34), and broad bean (Vicia faba) (18). Methods for studying ion uptake have included using whole cells, leaf slices and fragments, submerged leaves, and protoplasts.…”

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confidence: 99%

Stimulation of Growth and Ion Uptake in Bean Leaves by Red and Blue Light

Blum

Elzenga²,

Linnemeyer³

et al. 1992

Plant Physiol.

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Red and blue light both stimulate growth and ion accumulation in bean (Phaseolus vulgaris L.) leaves, and previous studies showed that the growth response is mediated by phytochrome and a bluelight receptor. Results of this study confirm that there is an additional photosynthetic contribution from the growing cells that supports ion uptake and growth. Disc expansion in the light was enhanced by exogenous K' and Rb', but was not specific for anions. Light increased K' accumulation and the rate of 'Rb' uptake by discs, over darkness, with no effect of light quality. The photosynthetic inhibitor, 3-(3,4-dichlorophenyl)-1,1-dimethylurea, inhibited light-driven "6Rb+ uptake by 75%. Light quality caused differences in short-term kinetics of growth and acidification of the leaf surface. At comparable fluence rates (50 ,umol m-2 s-'), continuous exposure to blue light increased the growth rate 3-fold after a 2-min lag, whereas red light caused a smaller growth response after a lag of 12 min. In contrast, the acidification of the leaf surface normally associated with growth was stimulated 3-fold by red light but only slightly (1.3-fold) by blue light. This result shows that, in addition to acidification caused by red light, a second mechanism specifically stimulated by blue light is normally functioning in lightdriven leaf growth.The expansion of dicotyledonous leaves is stimulated by light acting photomorphogenically through at least two photoreceptors, phytochrome and a blue-light receptor (for review, see refs. 9 and 14). For example, in primary leaves of bean (Phaseolus vulgaris L.), red and blue light both stimulate leaf expansion, but simultaneous exposure to far-red light significantly reduces growth only in red, but not blue, light (53). Photosynthesis is not necessary for light-stimulated growth (10, 52) but may enhance growth (10, 23, 52) and is known to be necessary for some light-driven transport processes (11,27,41,46). The stimulatory effect of light on growing leaves includes cell wall loosening and solute uptake for turgor maintenance (9). Cell expansion depends on acidification of the apoplast (50) and on acid-induced wall loosening (50, 54). Acidification may also be associated with the uptake of sugars and salts that is necessary for osmotic regulation by growing cells (8,15,32,45,51 of the cells, setting up a proton motive force that is used to drive uptake of sugars and ions (38).The mechanisms underlying light-driven leaf growth were addressed in this study. The photosynthetic dependence of K+ uptake associated with growth was investigated by measuring the effect of DCMU, an inhibitor of PSII, on accumulation of K+ and uptake of 86Rb+ by leaf discs. The stimulation of K+ and Rb+ uptake by light has been observed in Nitella (28), Vallisneria (39), corn (Zea mays) (40), green bean (Phaseolus vulgaris) (19), pea (Pisum sativum) (34), and broad bean (Vicia faba) (18). Methods for studying ion uptake have included using whole cells, leaf slices and fragments, submerged leaves, and protoplasts. A ...

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Foliar Absorption—an Active Uptake Process

Cited by 38 publications

References 22 publications

Fungal endophytes and epiphytes in needles ofPicea abies(L.) Karst. from natural and urban areas in northern Italy

Fungal endophytes and epiphytes in needles ofPicea abies(L.) Karst. from natural and urban areas in northern Italy

Ion Absorption in Atriplex Leaf Tissue I. Absorption by Mesophyll Cells

Stimulation of Growth and Ion Uptake in Bean Leaves by Red and Blue Light

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