摘要:

Long distance transport of sodium in bean plantsIn 8–10 days old bean plants Na+(22Na) has been applied to either a certain root zone, the stem, or the base and tip respectively of a primary leaf and the long distance transport of Na+was studied in the following 12–48 h.The long distance transport of Na+applied to the root zone 9–12 cm behind the tip was strongly restricted towards the shoot and hardly detectable towards the root tip (phloem transport). Presence of K+in the surrounding solution strongly increased the Na+efflux from the roots.After leaf application within 48 h 30–40% of the absorbed Na+had been translocated out of the leaf in direction of the root where, from the basal root zones, intensive Na+efflux took place. This Na+efflux was hardly affected by presence of K+in the external medium and was usually more than 10% of the Na+taken up by the leaves. From the Na+taken up by the hypocotyl within 12 h more than 25% had been released from the basal root zones into the nutrient solution. Less than 1% of the Na+applied either to the leaf or the stem was translocated towards the shoot apex.Separation of the hypocotyl into cortex and stele at the end of the experiment demonstrated the high capacity of the stele for Na+accumulation. Within the hypocotyl the transfer of Na+from the stele to the cortex and the phloem seems to be a rapid process whereas the release of Na+from the phloem into the stele is obviously very restricted. The long distance transport of Na+within the phloem of the shoot is strictly basipetal and very efficient. Low Na+contents of bean leaves are therefore the result of several regulating mechanisms: K+stimulated Na+efflux in the roots, restricted long distance transport in the xylem due to high Na+accumulation in the stele, Na+pumps at the phloem in stem and leaves for phloem loading of Na+, and finally strictly basipetal retranslocation of Na+in the phloem into the roots and efflux into the solution from basal roo

ISSN:0044-3263    

DOI:10.1002/jpln.19761390202

出版商:WILEY‐VCH Verlag    

年代:1976

数据来源: WILEY

摘要:

Influence of nitrogen nutrition and application of growth regulators on tuber initiation in potato plantsIn water culture the effect of continuous and discontinuous N‐nutrition on tuber initiation was investigated. Additional applications of growth regulators on growing stolon tips were carried out.Continuous supply of nitrate or ammonium inhibited completely the tuber initiation in S. tuberosum varieties „Ostara”︁ and „Clivia”︁, The inhibition was compensated by application of CCC and ABA on the stolon tip. In contrast to this stolon application of kinetin and root application of CCC were ineffective. Temporarily damaging of the root system led to tuber initiation even when nitrogen was supplied continuously. In S. andigena grown under short day continuous N supply only delayed the tuber initiation but could not prevent it.Discontinuous N supply promotes tuber initiation in S. tuberosum. A sudden increase in N supply caused „re‐growth”︁ of the tuber, i.e. a stolon was formed on the tuber apex. GA3application on the growing tuber had the same effect.The effect of N nutrition on tuber initiation can be explained via changing the balance of endogenous growth regulators in general and the physiological aging of the leaves in particular. Discontinuous N supply seems to reduce cytokinin production in roots and therefore accelerates the aging of the leaves. This in turn favours the formation of inhibitors and/or presumably reduces the GA production in the shoot, which will change the balance of the growth regulators in the stolon tip in favou

ISSN:0044-3263    

DOI:10.1002/jpln.19761390203

出版商:WILEY‐VCH Verlag    

年代:1976

数据来源: WILEY

摘要:

Influence of ripening, temperature and oxygen supply on the synthesis of unsaturated fatty acids and tocopherols in sunflower seedsThe ratio of vitamin E (tocopherol)/polyunsaturated fatty acids (T/PUFA) is of importance in the storage and consumption of oils and diets. In previous experiments low temperature and cool climate during seed development of sunflowers were found to decrease the T/PUFA in the seeds (BeringerandSaxena, 1968;Dompertet al., 1975). This may be due to a) a prolonged „filling period”︁ at low temperatures and/or b) a direct effect of temperature on the synthesis of oil and tocopherol in the seeds.Harvesting sunflower seeds, grown in a climate‐chamber at 22°C, at 1, 8, 15, 25, 31 and 40 days after pollination revealed an intensive lipid synthesis in the seeds between 8 and 31 days after pollination, thereafter a small decline of total lipids occured. Total tocopherols, with α‐tocopherol dominating, were synthesized nearly parallel to total lipids. Accordingly a ratio of 1 mg tocopherol/g seed‐oil and approximately 3–4 mg tocopherol/g linoleic acid respectively from 8 days after pollination till maturity was found.Increased growth temperatures (day and night same) from 10 to 22 up to 35°C from flowering till maturity caused a decrease in oil content and linoleic acid percentages. An attempt to compensate the stimulating effect of low temperatures on fatty acid desaturases by flushing sunflower‐heads with gas mixtures of 21% O2(10°C plants), of 28% O2(22°C plants) and 38% O2(35°C plants) according toHarrisandJames(1969) resulted in only slight increases of linoleic acid, which were with 23,5% at 35°C and 40,7% at 22°C still much lower than at 10°C, where linoleic acid was linoleic acid was 62,8% of total fatty acids. Under natural conditions a direct influence of growth temperature seems therefore more likely in determining the fatty acid composition than temperature dependant rates of O2‐diffusion into the seed tissue. Unlike fatty acid synthesis the synthesis of tocopherols was not significantly influenced by the growth temperature. But due to decreasing oil content and linoleic acid percentages at higher temperatures the α‐Tocopherol/g oil as well as the α‐tocopherol/g linoleic acid was continuously raised. The latter increased from 0,9 at 10°C up to 7,8 at 35°C i. e., the ratio of 1 I. U. vitamin E/g PUFA required in animal and human nutrition was achieved at all temperatures tested.The parallelism of oil‐ and tocopherol‐content in developing sunflower seeds on the one side and the large, temperature dependant variability of the T/PUFA‐ratio on the other side suggest, that no „stoichiometric”︁ relation exists between the synthesis of tocopherols and fatty acids in sunflower seeds. Fatty acid desaturases in oil seeds are membrane‐bound enzymes and tocopherol might be involved as an antioxydative stabilizer of the membrane as it

ISSN:0044-3263    

DOI:10.1002/jpln.19761390204

出版商:WILEY‐VCH Verlag    

年代:1976

数据来源: WILEY

摘要:

Electrochemical Behavior of Urea Soluble Components of Gluten Proteins of WheatProtein zones of urea soluble gluten proteins of wheat samples from different cultivars and locations were analyzed after 2 dimensional separation by sucrose‐density‐gradient isoelectric focusing and disk polyacrylamide‐gel electrophoresis.More than 50% of the urea soluble proteins was focused in a range from pH 6,5–7,6. The major concentration in all samples was observed close to pH 7,0 as indicated by the main peak in all absorption diagrams.Electrophoretic separation of proteins of equal isoelectric characteristics yielded fractions differing mainly in charges.Two dimensional separation yielded more than 40 protein fractions. The pattern of these fractions was more influenced by environmental effects than by cultivars. No relation between protein pattern and baking quality was o

ISSN:0044-3263    

DOI:10.1002/jpln.19761390205

出版商:WILEY‐VCH Verlag    

年代:1976

数据来源: WILEY

摘要:

Translocation of nitrogen to the shoot of young bean plants after uptake of NO 3−and NH 4+by the rootPhaseolus vulgarisplants (var.nana, cv. Saxa) at the primary leaf stage (without nodules) were fed during 6 hours with15NO 3−and15NH 4+, respectively. 24 hours after the absorption period more15N from the absorbed NO 3−was translocated from the root to the shoot. The presence of NH 4+in the nutrient solution enhanced the translocation of15NO 3−N, probably by an inhibition of nitrate reductase. NH4‐+15N is mainly retained in the root by a high incorporation into the root protein. It can be concluded that nitrogen from newly absorbed NO 3−is not retained and used for protein synthesis in the root according to the root's potential to synthesize protein. Nitrate reduction in the root is considered to be the limiting factor. This is supported by the fact that withdrawal of NO 3−in the nutrient solution prior to the15N‐experiment increased NO 3−translocation to the shoot as a consequence of a lowered level of nitrate reductase. In an experiment with14NO 3−supply to the roots and15NO 3−application to the primary leaves (infiltration method) a considerable amount of15N was translocated from the leaves to the roots. This indicates that an insufficient NO 3−reduction in the root can be substituted by a retranslocation of reduced N‐compounds from leaves to the roots. The proportion of NO 3−reduced in the root influences also the pattern of primary distribution of nitrogen in the shoot of plants at the 4 leaf stage. At a concentration of 0,2 meq/l NO 3−in the nutrient solution as compared to 20 meq/l NO 3−during 10 hours a relative higher amount of15N was transported from the root to the

ISSN:0044-3263    

DOI:10.1002/jpln.19761390206

出版商:WILEY‐VCH Verlag    

年代:1976

数据来源: WILEY

摘要:

Die Physiologie der Salzschädigung in der PflanzenproduktionDas Pflanzenwachstum bei verschiedener Salinität wird an einem Modell der Zellstrekkung untersucht. In diesem Modell wird angenommen, daß die Geschwindigkeit der Zellstreckung durch die Produktion von Osmolalität in der Zelle via Stofftransport begrenzt wird. Eine osmotische Anpassung, d.h. konstanter Turgordruck, wird vorausgesetzt.Modell und Beobachtungen stimmen in folgenden Punkten überein: a) Es gibt eine optimale äußere Lösungskonzentration, bei der die Zellstreckungsrate maximal ist, b) bei hohen Salzkonzentrationen nimmt die Zellstreckungsrate trotz osmotischer Anpassung ab, c) niedere (stark negative) Wasserpotentiale, die durch nicht aufnehmbare Osmotika (oder durch eine Matrix) verursacht werden, reduzieren immer die Zellstreckungsrate, d) in Mischlösungen verschieben die nicht aufnehmbaren Osmotika die Optimumkonzentration aufnehmbarer Osmotika zu höheren Werten. Die Zellstreckungsraten werden dabei aber kleiner. e) Schnelle Stoffaufnahme bedeutet größere Produktion von Osmolalität im Zellsaft und fördert dadurch die Zellstreckung. b) Während des nicht stationären Zustandes, der auf eine Versetzung von Geweben aus verdünnten in mehr konzentrierte Lösungen folgt, verschiebt sich das Optimum allmählich zu höheren äußeren Konzentrationen.Stoffaufnahme und Auxinwirkung zeigen verschiedene pH Optima bei der Zellstreckung. Die Zellstreckungsrate wird durch das pH Optimum der Stoffaufnahme dominiert außer in Anfangsstadien.Die Teilungsrate vonScenedesmus quadricaudazeigt ebenfalls eine optimale äußere Konzentration. In konzentrierten Lösungen werden weniger, dafür ab

ISSN:0044-3263    

DOI:10.1002/jpln.19761390207

出版商:WILEY‐VCH Verlag    

年代:1976

数据来源: WILEY

摘要:

Die Rolle des Magnesiums in der PflanzenernährungIn dem Beitrag wird die Bedeutung des Mg in der Pflanzenernährung diskutiert. Er behandelt den Boden in seiner Eigenschaft als Mg‐Quelle der Pflanze. Aufnahme und Verteilung von Mg in der Pflanze, physiologische Funktionen des Mg, Mg‐Mangel und die Rolle des Mg bei der Ernährung von Kulturpf

ISSN:0044-3263    

DOI:10.1002/jpln.19761390208

出版商:WILEY‐VCH Verlag    

年代:1976

数据来源: WILEY

摘要:

Cu, Co and Mo in sesquioxide accumulation horizonsFe, Mn, Cu, Co and Mo were determined in 1) a podzol‐gley‐ and 2) a pseudogley brownearth — stagnogley — „ochre earth”︁‐landscape. In landscape 1) the accumulation of Fe in the gley — Gois pronounced and the translocation Mn>Cu, whereas landscape 2 is characterized by the accumulation of Mn in the „ochre earth”︁ and by a translocation Co>Cu (Mo shows just small differences in 1) and 2)). The relation between the distribution of Cu, Co and Mo and of sesquioxides is overlapped by the influence of organic matter. From larger concentration differences for both Mn and Co in landscape 2 as compared to 1 a special role of manganese oxides for the accumulation of Co can be concluded. This accumulation however is not connected with a

ISSN:0044-3263    

DOI:10.1002/jpln.19761390209

出版商:WILEY‐VCH Verlag    

年代:1976

数据来源: WILEY

摘要:

Effect of Late Application of Nitrogen on the Grain Protein of a Maize Hybrid Rich in Lysine1. In pot experiments the influence of an additional late N fertilizer application at time of flowering on a high yielding lysine‐rich experimental maize hybrid has been determined.2. N‐fertilization at flowering increased the total‐N and the lysine‐contant of the grains. The lysine‐N in % of total‐N was constant at 5,1%. Comparable values from a former investigation with an opaque‐ and a standard hybrid are 6,0% lysine‐N and 4,0% lysine‐N of total‐N, respectively.3. The ratio of prolamine to gluteline was 1:1. N‐fertilization did not change this ratio.4. The amino‐acid pattern of the single protein fractions, albumine globuline, prolamine and gluteline was very different, but it was not changed by N‐fertilization.5. Dissecting embryo and endosperm, demonstrated that by late N‐fertilization the growth of embryo was promoted more than that of the endosperm. The embryo contributed 30% to total‐N and 44% to total‐lysine‐N of the grain and was not changed by the late N‐application.6. At cultivating such improved hybrids it may be expected that the protein quality will not be changed by application of high amounts of N‐fertilizer, whereas t

ISSN:0044-3263    

DOI:10.1002/jpln.19761390210

出版商:WILEY‐VCH Verlag    

年代:1976

数据来源: WILEY

摘要:

The Uptake and Distribution of15N‐Labelled Urea byPhaseolus vulgarisLThe uptake of two‐fold15N‐labelled urea via the root system of 21 days old plants of Phaseolus vulgaris in comparison with15N‐marked ammonium chloride has been investigated. The concentration of urea or ammonium resp. was 3 mmol/l. The plants were allowed to take up the labelled nitrogen for an 8 hours period. The determination of the15N‐frequency was carried out by emission spectrometry.The results demonstrate that urea is taken up as a whole undestructed molecule. Also there is evidence for a 7‐fold enrichment of urea in the exsudation sap in comparison with the urea concentration in the nutrition solution. Inhibition of the metabolic activity of the roots (2,4‐DNP, KCN, AsO4, N2) reduces both the urea and the ammonium absorption to a considerable rate. Variations of the transpiration, of the Ca/K ratios or pHin the nutrition solution have none or only a very small influence on the uptake of urea. There may be the possibility for the existence of a common mechanism for the absorption of both urea

ISSN:0044-3263    

DOI:10.1002/jpln.19761390211

出版商:WILEY‐VCH Verlag    

年代:1976

数据来源: WILEY