Gibberellic Acid effects on greening in pea seedlings

The effect of gibberellic acid (GA) on light-induced greening of etiolated pea plants (Pisum sativum [L.] cultivars Alaska and Progress) was characterized. Progress, a GA-deficient dwarf of Alaska, was found to accumulate chlorophyll and light harvesting chlorophyll protein associated with photosystem II (LHC-II) more rapidly than Alaska, Alaska treated with GA, or Progress treated with GA. A slightly lower chlorophyll content was noted after 24 hours of light induced greening for Alaska treated with GA relative to untreated Alaska. GA-treated Progress, Alaska, and GA-treated Alaska all gave essentially identical patterns for LHC-II accumulation. Similar patterns of LHC-II mRNA induction were found in all four treatments indicating that differences in mRNA induction did not cause differences in LHC-II accumulation. Chlorophyll and LHC-II accumulation in each treatment followed the same patterns of accumulation and a significant correlation (at the 0.01 level of significance) was found between chlorophyll and LHC-II content. Since Progress treated with GA accumulated LHC-II and chlorophyll in a manner similar to that of Alaska, it is clear that GA alters the process of greening either directly or indirectly.     

Amino Acid Release from the Seed Coat of Developing Seeds of Vicia faba and Pisum sativum

After removal of the embryo from developing ovules of Viciafaba L. and Pisum sativum L., seed-coat exudates were collectedand the amino acid fraction of the exudate was analyzed. InV. faba, alanine was the most important compound of the aminoacid fraction. In P. sativum, alanine and glutamine were thetwo most important components, whereas only small amounts ofasparagine were present. Comparison with published data suggeststhat seed-coat exudates may differ from phloem sap in the relativeimportance of these amino acids. Pisum sativum, pea, Vicia faba, broad bean, amino acid transport, amino acid unloading, seed-coat exudate, seed development     

The Relationship of Endogenous Gibberellins to Light-regulated Stem Elongation Rates in Dwarf and Normal Cultivars of Pisum sativum L.

Dwarf cultivar Progress No. 9 and normal cultivar Alaska ofPisum sativum L. were grown under conditions of darkness orred light. Red light decreased the stem elongation rate of bothcultivars. Gibberellins present during the linear phase of stemelongation were isolated and the two main components were tentativelyidentified by gas chromato-chromatography and mass spectrometryas Gibberellin A₁ and A₅. Both gibberellins varied quantitativelywithin and between cultivar and treatment groups, and the amountspresent were inversely related to stem elongation rate. Althoughthe stem elongation rate of plants grown under red light wasrepressed, endogenous gibberellin was not limiting and was asmuch as two-fold higher in red light-grown plants than in dark-grownplants. The levels of endogenous gibberellin in dawrf plantsindicated that the genetic growth limitation was not due toa gibberellin deficiency. (Received May 26, 1981; Accepted January 28, 1982)     

Absence of Red Light-Induced Stimulation of Growth in the Hook of Etiolated Dwarf-Pea Seedlings

Red light inhibited the growth of the apical part of the hookin dark-grown seedlings of a dwarf variety (cv. Progress No.9) of pea (Pisum sativum L.), whereas it promoted such growthin a tall variety (cv. Alaska). In the elongation zone of theepicotyl of the dwarf variety the extent of inhibition of growthwas similar to or even smaller than that in the tall variety.Local irradiation of the apical part of the hook also causedinhibition of growth in the hook of the dwarf variety and promotionof growth in the tall variety. The inhibition of growth in theapical part of the hook of cv. Progress may be involved in thedwarfism induced by irradiation with red light of this cultivar. (Received May 15, 1989; Accepted April 27, 1990)     

The Distribution of {beta}-Glycerophosphatase in Young Roots of Pisum sativum L.

The distribution of ß-glycerophosphatase activityin young roots of Pisum sativum, cultivar Alaska, has been examinedby biochemical and histochemical methods. Results obtained bythe two approaches are broadly similar, and indicate that highenzyme activity is associated with cells of the root cap, outerlayers of the cortex, differentiating xylem elements and phloemfibres, and cortical cells surrounding emerging lateral roots.The significance of this distribution in relation to a possiblefunction of ß-glycerophosphatase is discussed.     

Assessment of changes in physiological and biochemical traits in four pistachio rootstocks under drought,salinity and drought + salinity stresses

In this study, 7-month-old UCB-1, Badami, Ghazvini and Kale-Ghouchi pistachio rootstocks were exposed to control, drought, salinity and drought + salinity environments for 60 d. Total chlorophyll and total carotenoid contents decreased in all cultivars under drought, salinity and drought + salinity stresses. Under drought and salinity stresses, alone or in combination, Na⁺ and Cl⁻ ions increased in all four pistachio rootstocks, while K⁺ ion decreased only in Ghazvini and Kaleh-Ghouchi cultivars. The enzyme activities of ascorbate peroxidase, polyphenol oxidase, catalase and guaiacol peroxidase increased in all cultivars when subjected to all three stresses with the exception of the ascorbate peroxidase activity in Kale-Ghouchi cultivar during drought stress. Oxidative stress parameters including electrolyte leakage, malondialdehyde, other aldehydes and hydrogen peroxide increased under all three stress conditions in all genotypes. The content of proline, total free amino acids and total soluble carbohydrates were enhanced under drought, salinity and drought + salinity stresses, whereas the protein content decreased in all pistachio rootstocks. In all evaluated traits, except for the K⁺ ion content and APX activity, the highest impacts was seen for drought + salinity > salinity > drought stresses, respectively. For the first time, we have proven that K⁺ ion content has a positive correlation with the ascorbate peroxidase, polyphenol oxidase, catalase and guaiacol peroxidase enzymes activities under drought + salinity stress. Finally, based on the bi-plot and cluster analyses, we have selected the UCB-1 > Badami > Ghazvini > Kale-Ghouchi cultivars as the most tolerant pistachio rootstocks under drought + salinity stress, respectively.     

Changes Induced by Salinity to the Anatomy and Morphology of Excised Pea Roots in Culture

Excised pea roots were grown in culture in the absence or presenceof NaCl. Salinity induced anatomical and morphological changesin the roots, some of which could be observed after only 24h in culture. Roots became constricted just above the apex,the region above the constriction thickened and the root tipcurved through 90°. Cellular differentiation began nearerthe apex, cortical and epidermal cells shortened and mitoticactivity in the pericycle increased as a result of exposureto salinity. Some of the changes resemble those induced by ethylene,but ethylene probably was not the cause of the response to salinity.Root cultures seem to be a suitable model for studying the effectof salinity in plant roots. Pisum sativum cv. Alaska, salinity, roots, cortex, root culture, pericycle, growth and differentiation     

Salt-induced Changes in the Distribution of Amyloplasts in the Root Cap of Excised Pea Roots in Culture

The effects of 120 mM NaCl on the anatomy and ultrastructureof the root tip of cultured excised pea roots was investigatedafter 24 h exposure to salinity. In the meristematic cells mitochondrialdamage was apparent and these cells showed increased vacuolation.The root cap was already severely affected after 24 h exposureto salinity and clumping of the cap amyloplasts around the cellnuclei was apparent. The possibility that salinity may affectroot gravitropic responses is discussed. Pisum sativum L. cv. Alaska, salinity, roots, root culture, amyloplasts, ultrastructure     

Characteristics of Sugar, Amino Acid and Phosphate Release from the Seed Coat of Developing Seeds of Vicia faba and Pisum sativum

After removal of the embryo from developing seeds of Vicia fabaL. and Pisum sativum L., the ‘empty’ ovules werefilled with a standard solution (pH 5.5). Seed coat exudatesof both species were collected during relatively long experiments(up to about 12 h) and the concentration of sugar (mainly sucrose),amino acids and phosphate in the exudate measured. A discussionis presented on the amino acid/sugar ratio and the phosphate/sugarratio in the seed coat exudate. A pretreatment (15 min) withp-chloromercuribenzenesulphonic acid (PCMBS) reduced the releaseof sugar, amino acids and phosphate from broad bean seed coats.After excision of ‘empty’ ovules of Vicia faba andPisum sativum from the maternal plant, 2–4 h after thistreatment a strong difference became visible between sucroserelease from excised seed coats and sucrose release from attachedseed coats. Similarly, when the rate of phloem transport ofsucrose into an ‘empty’ ovule of Vicia faba or Pisumsativum was reduced by a sub-optimal mannitol concentrationin the solution, a reduced rate of sugar release from the seedcoat could be observed. Excision and treatment with a sub-optimalmannitol concentration reduced the release of amino acids toa lesser extent than for sucrose. These treatments did not reducethe rate of phosphate release from the seed coat. Key words: Seed development, Seed coat exudate, Phloem transport     

Ion Absorption and Allocation of Carbon Resources in Excised Pea Roots Grown in Liquid Medium in Absence or Presence of NaCl

Freshly excised pea roots (Pisum sativum cv. Alaska) when transferredto growth medium (130 mOsm) or growth medium containing salt( 370 mOsm) suffer an initial osmotic shock and lose water.Contol roots tended to accumulate potassium, particularly inthe apical zone, while those exposed to NaCl accumulated mainlysodium, potassium accumulation being depressed. Exposure tosalinity for 6 d caused increases in root protein, cellulose,uronic acid and lignin content per cell. In roots supplied with¹⁴C-glucose for 24 h immediately after excision there was littledifference in uptake of glucose and in its use in respirationbetween control and salt treated roots. However, there werenoticeable differences in incorporation of labelled carbon intoseveral cell fractions, and particularly into the cellulosefraction in the upper parts of the root. When roots were grownfor six days in culture before being supplied with [¹⁴C]glucose,uptake per root was greater in the 120 mM NaCl treatment, andthe fraction diverted to respiration was decreased by salinity.On a per cell basis incorporation into soluble starch, uronicacid and cellulose fractions was increased in the salt treatedroots. The data obtained are in accord with the previous findingsand are suggestive of increased synthesis of cell wall materials.No conclusion could be drawn as to whether the changes describedare of adaptive value. Pisum sativum L. cv. Alaska, root culture, salinity, osmoregulation, cell wall     

Changes in the Organic Acid Content of some Cultivated Plants Induced by Mineral Ion Deficiency

Four plant species (Zea mays, Lolium italicum, Phaseolus vulgaris,and Pisum sativum) were grown either with full nutrient supplyor with calcium, potassium, or nitrogen deficiency. After 4–6weeks the shoots were analysed for their content of K⁺, Ca²⁺,Mg²⁺, and Na⁺, of total anions, and of organic acids. The qualitativepattern of organic acid components, characteristic of each species,remained, with few exceptions, unchanged by deficiency treatments.Striking differences were detected in the total acid contentand in the quantities of the respective main organic acid components,especially in potassium-deficient plants. These changes showedstrong correlations with alterations of cation excess and demonstratethat aconitate in Zea mays, malonate in Phaseolus vulgaris,and citrate in Pisum sativum contribute to charge balance.     

Neutral growth inhibitors in light-grown dwarf pea shoots –separation, identification and growth regulation

To correlate endogenous growth inhibitors of dwarf pea to its dwarfism a thorough search of growth inhibitors was made in the neutral fraction of an acetone extract from the shoots of light-grown seedlings of Pisum sativum L. cvs Progress No 9 and Alaska. From both cultivars six inhibitors were separated and named A-1, A-2, A-3, B-1, B-2 and B-3 based on their order of elution from the silica gel column. Their contents as determined by cress root bioassay were: in cv. Progress 0.40, 16.5, 6.36, 1.02, 0.11 and 0.10, and in cv. Alaska 0.33, 2.35, 3.51, 0.95, 0.10 and 0.09 cress units (g fresh weight)⁻¹. Their contributions to growth regulation of the relevant pea plants were estimated as the products of the above-stated contents times the ratios of the specific activities of each standard sample in the cress roots and the relevant pea cultivars, and they were; in cv. Progress A-2, 5.44 and A-3, 2.10, and in cv. Alaska A-2, 0.68 and A-3, 0.88, those of A-2 and A-3 constituting more than 90% of the total contribution of the six inhibitors in either cultivar. The great differences in the content and contribution to growth regulation of A-2 and A-3 between the two cultivars suggest that the higher contents of and greater responsiveness to the two inhibitors in cv. Progress may be causes of dwarfism of this cultivar. A-l and A-3 were spectroscopically identified with pisatin and a mixture of cis, trans– , and trans, trans xanthoxins.     

Inheritance of cyanide-resistant respiration in two cultivars of pea (Pisum sativum L.)

Abstract Two pea cultivars (Pisum sativum L., cvs. Alaska and Progress No. 9) shown previously to differ with regard to the appearance of the cyanide-resistant (alternative) pathway of respiration in axis tissue, were found to show this same difference in mature leaf tissue and in epicotyl mitochondria. The possible relationship between dwarf growth form and lack of alternative respiration in cv. Progress No. 9 was tested in two ways. When dwarfism was alleviated in Progress No. 9 by application of exogenous gibberellin A₁, no appearance of the alternative pathway was observed. In a survey of eight other dwarf pea cultivars, five were found to have an alternative pathway comparable to that shown by the tall cv. Alaska, while three lacked the pathway (cf. Progress No. 9). In reciprocal crosses between Alaska and Progress No. 9, the alternative pathway capacity of F₁ progeny resembled that of the maternal parent. This pattern was maintained in all the F₂ generation, indicating maternal inheritance of the trait. These data suggest that alternative respiration in pea is, to some extent, under the control of an organellar genome.     

The response of Mo-hydroxylases and abscisic acid to salinity in wheat genotypes with differing salt tolerances

The differential responses of the wheat cultivars Shi4185 and Yumai47 to salinity were studied. The higher sensitivity of Yumai47 to salinity was linked to a greater growth reduction under salt stress, compared to more salt-tolerant Shi4185. Salinity increased the Na⁺, proline and superoxide anion radical (O₂ ^?) contents in both cultivars. Leaf Na⁺ content increased less in the more salt-tolerant cultivar Shi4185 than salt-sensitive Yumai47. The proline content increased more significantly in Shi4185 than Yumai47; on the contrary, superoxide anion radical content increased less in Shi4185 than Yumai47. This data indicated that wheat salinity tolerance can be increased by controlling Na⁺ transport from the root to shoot, associated with higher osmotic adjustment capability and antioxidant activity. Although salinity increased aldehyde oxidase (AO) activity and abscisic acid (ABA) content in the leaves and roots of both cultivars following the addition of NaCl to the growth medium, AO and ABA increased more in the salt-sensitive cultivar Yumai47 than the more salt-tolerant cultivar Shi4185. Xanthine dehydrogenase (XDH) activity in the leaves of both cultivars increased with increasing concentrations of NaCl; however, leaf XDH activity increased more significantly in Yumai47 than Shi4185. Root XDH activity in Shi4185 decreased with increasing NaCl concentrations, whereas salinity induced an increased root XDH activity in Yumai47. The involvement of AO and XDH enzymatic activities and altered ABA content in the response mechanisms of wheat to salinity are discussed herein.     

Gibberellins in immature seeds and dark-grown shoots of Pisum sativum

Gibberellins (GAs) A₁₇, A₁₉, A₂₀, A₂₉, A₄₄, 2OH-GA₄₄ (tentative) and GA₂₉-catabolite were identified in 21-day-old seeds of Pisum sativum cv. Alaska (tall). These GAs are qualitatively similar to those in the dwarf cultivar Progress No. 9 with the exception of GA₁₉ which does not accumulate in Progress seeds. There was no evidence for the presence of 3-hydroxylated GAs in 21 day-old Alaska seeds. Dark-grown shoots of the cultivar Alaska contein GA₁, GA₈, GA₂₀, GA₂₉, GA₈-catabolite and GA₂₉-catabolite. Dark-grown shoots of the cultivar Progress No.9 contain GA₈, GA₂₀, GA₂₉ and GA₂₉-catabolite, and the presence of GA₁ was strongly indicated. Quantitation using GAs labelled with stable isotope showed the level of GA₁ in dark-grown shoots of the two cultivars to be almost identical, whilst the levels of GA₂₀, GA₂₉ and GA₂₉-catabolite were significantly lower in Alaska than in Progress No. 9. The levels of these GAs in dark-grown shoots were 10²- to 10³-fold less than the levels in developing seeds. The 2-epimer of GA₂₉ is present in dark-grown-shoot extracts of both cultivars and is not thought to be an artefact.Abbreviations cv cultivar - GA_n gibberellin A_n - GC gas chromatography - GC-MS combined gas chromatographymass spectrometry - HPLC high-pressure liquid chromatography - KRI Kovats retention index - MeTMSi methyl ester trimethylsilyl ether     

The fractionation of transfer ribonucleic Acid from roots of pea seedlings

Isoaccepting transfer RNA species for several amino acids were fractionated by reverse phase column chromatography. Transfer RNA from dividing cells of pea (Pisum sativum) root was compared to that from nondividing cells, and no relative quantitative or qualitative differences were noted for the transfer RNA species for leucine, lysine, proline, threonine, methionine, serine, and phenylalanine. However, certain artifactual differences for serine and phenylalanine were noted. Quantitative differences were observed in tyrosyl-transfer RNA's. Ribonuclease action on tRNA did not contribute to the tRNA species observed.     

The Basis for Different Sensitivities of Photosynthesis to SO2 in Two Cultivars of Pea

Alscher, R., Bower, J. L. and Zipfel, W. 1987. The basis fordifferent sensitivities of photosynthesis to SO₂ in two cultivarsof pea.—J. exp. Bot. 38: 99–108. The response of several physiological parameters to exposureto SO₂ (0?8 ppm and 0?6 ppm) was studied in two cultivars ofPisum sativum in which photosynthesis showed a different sensitivityto SO₂. Leaf conductance was slightly reduced during exposureto SO₂ in the sensitive but not the insensitive cultivar. Moresulphite accumulated in the leaves of the sensitive than inthose of the insensitive cultivar. Total leaf content of reducedglutathione in the insensitive cultivar increased during exposureto SO₂, while in the sensitive cultivar there was no increaseuntil the post-exposun period. The activities of fructose l,6-bisphosphataseand glyceraldehyde-3-phosphate dehydrogenase did not decreasegreatly in either cultivar, although activities of enzymes fromthe sensitive cultivar were more affected by SO₂ than were thoseof the insensitive cultivar. Exposure to SO₂ also had littleeffect on either coupled or uncoupled electron transport ofisolated thylakoids from the leaves of either cultivar. Increasedglutathione in the insensitive cultivar may protect the photosyntheticapparatus against SO₂ Key words: SO₂, photosynthesis, light modulation, glutathione     

Cytochemical localization of ATPase plasma membrane and acid phosphatase by cerium-based method in a salt-adapted cell line of Pisum sativum

In order to study a possible application of cerium-based techniquesin plant cells, ATPase and acid phosphatase activities havebeen compared in two cell lines of Pisum sativum calli, onesensitive to NaCI and the other selected to be grown under salinity(85 mM NaCI). ATPase activity was unchanged and localized inthe plasma membrane of both cell lines. Acid phosphatase activitywas significantly increased in the salt-selected line and localizedin the cell walls, Golgi complex, multivesicular bodies andvacuoles. These results indicated a possible involvement ofboth activities in the maintenance of cell growth in the selectedline under saline conditions. Key words: Acid phosphatase, Pisum sativum, plasma membrane ATPase, salt stress, ultrastructure     

Salinity Stress and the Content of Proline in Roots of Pisum sativum and Tamarix tetragyna

Amino acid composition of the free amino acid pool and the TCA-insolubleprotein fraction were investigated in root tips of pea and Tamarixtetragyna plants grown at various levels of NaCl salinity. Salinitystress induced an increase of proline content, mainly in thefree amino acid pool in both plants, and of proline or hydroxyprolinecontent in the protein. Externally-supplied proline was absorbedand incorporated into protein, by pea roots, more effectivelythan by Tamarix roots. Salinity stress, apparently, stimulatedthe metabolism of externally-supplied labelled proline. Pearoots have a very large pool of free glutamic acid; however,70 per cent of the ¹⁴C from externally-supplied ¹⁴C-U-glutamicacid was released as CO₂. Very small amounts of it were incorporatedinto protein. No measurable amount of radioactivity could bedetected in any one of the individual amino acids, either ofprotein hydrolysate or the free amino acid pool. Proline very effectively counteracted the inhibitory effectof NaCl on pea seed germination and root growth. A similar effectbut to a lesser degree was achieved with phenylalanine and asparticacid. The feasibility of proline being a cytoplasmic osmoticumis discussed.