Changes in Protein Composition and the H+-ATPase Activity of the Plasma Membrane during Induction of Callus from Tuber Tissues of Jerusalem Artichoke

Changes in composition and synthesis of the proteins in plasmamembranes during early periods of induction of callus from tubertissues of Jerusalem artichoke were examined in relation toanalogous changes in H⁺-ATPase activity. By the 12th h of culture,vanadate-sensitive ATPase activity had increased more than 3.5-fold.The level of a polypeptide with a molecular mass of 97 kDa,which putatively corresponded to a subunit of the plasma membraneH⁺-ATPase, also showed a similar increase. Increases in ATPaseactivity and in the level of the 97-kDa polypeptide occurredindependently of the presence of 2,4-D in the culture mediumbut the rate of increase in both cases was slightly higher fortissue disks cultured with 2,4-D than for the control disksin medium without 2,4-D for the first 12 h of culture. The increasein the level of the 97-kDa polypeptide may be ascribed predominantlyto synthesis de novo during the early period of culture. Enhancedsynthesis of the 97-kDa polypeptide in the cultured tissuesmay have resulted in the increases in ATPase activity. Sinceauxin itself may stimulate H⁺-ATPase activity, the activatedH⁺-ATPase may be further stimulated in tissue disks culturedwith 2,4-D. The H⁺-ATPase activated in this way may produceconditions that facilitate the induction of callus from tubertissues of Jerusalem artichoke during the early period of culture. (Received July 13, 1992; Accepted October 19, 1992)     

The Effects of Growth Substances and Retardants on Renewed Growth Processes of Jerusalem Artichoke Tuber Tissues2

Inhibitors of gibberellin biosynthesis, and also precursorsof the hormone, were used to investigate the control of renewedgrowth processes of tuber tissue. It is concluded that renewedgrowth, as shown by invertase synthesis in tissue discs, andby sprouting of intact tubers, is under the early influenceof gibberellin biosynthesis, but the release of some gibberellinfrom a bound form cannot be ruled out.     

烟草愈伤组织生长和衰老期间呼吸代谢的改变

前人(Ross和Thorpe 1973,Thorpe和Laishley 1973,Brown和Thorpe 1982)曾报道了烟草愈伤组织芽形成期间呼吸速率、线粒体活性、底物代谢途径和有关呼吸酶活性的变化。我们对烟草愈伤组织呼吸代谢的研究证明:组织分化和芽原基的形成与HMP途径运行升高相联系(毕玉蓉和梁厚果1987);愈伤组织的呼吸链存     

Ultrastructural Changes in the Nucleoli of Jerusalem Artichoke (Helianthus tuberosus) Tuber Discs

Discs cut from Jerusalem artichoke (Helianthus tuberosus) tubertissue were shaken in distilled water at 25?C (termed ageing)for periods of 0, 3, and 24 h when samples were prepared forelectron microscopy. Tissue samples were fixed with 3 per centbuffered glutaraldehyde followed by osmium tetroxide. The ultrastructureof the nucleolus changes significantly with ageing. By 3 h aregion which we identify as nucleolar-organizing chromosomeis beginning to move from an external position on the nucleolusinto the fibrillar region. By 24 h this chromosomal region hasbecome dispersed as small areas within the fibrillar zone. Atthe same time the nucleolus develops a large granular zone.These changes are discussed with reference to the known increasein RNA synthesis during the ageing process.     

Chloramphenicol Induced Changes in Some Respiratory Characteristics of Potato Tuber Callus

Chloramphenicol (CAP), an inhibitor of the mitochondrial proteinsynthesis inhibits callus induction and subsequent growth ofpotato tuber tissue discs. Tissue respiration increase did notoccur in the presence of CAP. Both with and without CAP theinitially CN^–-sensitive tissue becomes totally CN^–-resistantin 1–2 weeks. CAP blocks the development of mitcohondrial cytochrome oxidase.A gradual decrease in the activities of cytochrome oxidase andof cytochrome pathway-mediated mitochondrial respiration isfound in CAP-tissue. The mitochondrial alternative pathway whichis absent in mitochondria from freshly sliced tissue developsduring incubation both in the absence and presence of CAP. Thealternative pathway is only operative in uninhibited state IIIrespiration in mitochondria from CAP-tissue. Cycloheximide, an inhibitor of the cytoplasmic protein synthesisinhibits the developments of the alternative pathway and ofthe cytochrome pathway. Alcohol dehydrogenase activity increasestenfold in the tissue during two weeks of incubation on mediawith and without CAP. Alcohol production in the tissue did nottake place in the controls nor in the CAP-treated tissue. (Received April 18, 1981; Accepted July 17, 1981)     

Changes Accompanying the Addition of 2, 4-D to Excised Jerusalem Artichoke Tuber Tissue

Cultured in the absence of 2, 4-D, explants excised from Jerusalemartichoke tubers show no measurable increase in cell-number,fresh weight, or DNA content and only a small increase in RNAand protein. Consequent on the addition of 2, 4-D all theseparameters increase rapidly. A detailed study of the eventsimmediately following the addition of 2, 4-D after 5 days' culturein a mineral salts and sucrose medium shows the induction ofDNA replication prior to synchronous cell division in about35 per cent of the cells. It is a feature of this experimentthat large-scale RNA accumulation occurs only in cells preparingfor this division while RNA accumulated in most of the remainingcells before the addition of 2, 4-D is lost. The possible roleof 2, 4-D in the induction of cell division is discussed.     

RNA Accumulation in Relation to DNA and Protein Accumulation in Jerusalem Artichoke Callus Cultures

RNA accumulation during the synchronous early development ofJerusalem artichoke callus cultures follows a pattern of threestepwise increases in RNA per dividing cell during the firstdivision cycle. Little accumulation occurs in non-dividing cellsduring this time. These data are compared with data availablefor DNA replication, which occurs only in dividing cells, andfor protein accumulation which follows a similar pattern tothat of RNA accumulation in dividing cells, both in dividingcells and in some non-dividing cells.     

Protein Changes Associated with Adventitious Root Formation in Hypocotyls of Pinus Radiata

The changes in soluble proteins associated with adventitious root formation in hypocotyls of radiata pine (Pinus radiata D. Don) were studied using one- and two-dimensional polyacrylamide gel electrophoresis. Protein content decreased during the first day after root excision, and kept decreasing till the end of the time course under non-rooting conditions, i.e., on medium without growth regulators, with indole-3-butyric acid (IBA) + kinetin, or with kinetic alone. During adventitious root initiation in response to IBA, however, the protein content began to increase from day 1 to its maximum at day 7, coinciding with the early stage of root initiation. A comparative analysis of protein changes by two-dimensional polyacrylamide gel electrophoresis showed 16 proteins that were probably associated with root initiation and development.     

Morphactin and Adventitious Root Formation in Pea Cuttings

Stock plants of pea (Pisum sativum L. cv. Alaska) were grown at different controlled levels of irradiance (4, 16 or 38 W m^?2) for 11 days from sowing. Morphactin (CFM, methyl-2-chloro-9-hydroxy-fluorene-9-carboxylate) was applied to the apex of the stock plants 3 days before cuttings were excised. The cuttings were rooted at 16 W m^?2. High levels of morphactin (>5 × 10^?3 mg l^?1) inhibited root formation in the cuttings. Low concentrations of CFM (5 × 10^?5 mg l^?1) promoted the formation of adventitious roots in cuttings from plants grown at all three levels of irradiance, with the most pronounced effect in cuttings from 4 W m^?2. Measurements of ethylene evolution by CFM-treated plants 3 days after application, revealed a stimulatory effect on ethylene production by high CFM concentrations.     

Adventitious Root Formation in Veronica Spp.

Species of the genus Veronica differ in habitat preferences,growth form and in adventitious root production. The annualspecies rarely or never produce adventitious roots in intactplants in the field but some, for example V. persica and V.arvensis will root vigorously from single node stem segmentsin culture. Others, such as V. agrestis require the presenceof IAA for substantial levels of root formation to occur incultured stem segments. Veronica hederifolia cuttings rarelyproduce roots. Stem cuttings of the perennial species, in general,rooted more vigorously than those of annual plants. Both V.fihiformis and V. serpyllifolia root very strongly. The position of root production from the stem cuttings differedfrom species to species. Roots arose either from the node, theregion of the base or at some intermediate point. Veronica arvensis,V. chamaedrys and V. persica rooted mainly from the basal regionwhereas V. filiformis rooted mainly from the node. Veronicaserpyllifolia cuttings rooted at both of these locations. Veronica filiformis, a perennial species that is infertile inBritain, produces root primordia in intact plants at nodes whichare close to the shoot apex. Thus, even very young stem segmentshave ‘preformed’ root primordia. For this reason,detached stem segments of V. filiformis root very rapidly andthis probably has been of great significance in its successfulinvasion and spread in lawns and short turf areas. Veronica spp., adventitious roots, indol-3-ylacetic acid, root primordia, vegetative reproduction     

The Pattern of Protein Accumulation in Relation to DNA Replication in Jerusalem Artichoke Callus Cultures

While the synchronous first division cycle in cultured explantsfrom Jerusalem artichoke tubers may vary in duration from oneto two days the length of the ‘S’ phase of thiscycle remains approximately constant at 14 h. A study of thepattern of protein accumulation in relation to this ‘S’phase shows the development of three different populations ofcells in an initially uniform explant. Cells from the centreof the explant accumulate neither DNA or protein while cellsin the peripheral layers accumulate protein according to thesame pattern irrespective of whether they synthesize DNA ornot. This similarity between dividing and nondividing cellsis of interest in considering cellular events leading to celldivision.     

Steroidal Oestrogens and Adventitious Root Formation in Phaseolus Cuttings

Solutions of oestrone, oestrone-phosphate, oestrone-sulphate,oestradiol and oestradiol-sulphate in the concentration range10^–3 mol m^–3 to 10^–7 mol m^–3 had noobservable morphological or anatomical effects on adventitiousroot formation in Phaseolus vulgaris hypocotyl, epicotyl andprimary leaf cuttings. Oestradiol-sulphate and oestrone-sulphatetreatments at 0.1 mol m^–3 significantly inhibited rootingin hypocotyls, and the inhibition was almost complete in epicotylsand primary leaves. In the latter, anomalous development ofvascular tissues was noted. However, neither oestrone-phosphateat 0.1 mol m^–3 nor direct application of up to 100 µgof the oestrogens to apices or primary leaves of explants modifiedthe pattern of root formation. The results are discussed withreference to the distributive and metabolic fates of the appliedsubstances. Phaseolus vulgaris L., bean, adventitious roots, steroidal oestrogens, translocation     

不定根形成与植物激素的关系

不定根形成的关键是其原基的形成,是一个受激素调控的复杂过程,生长素起关键的调节作用.该文介绍生长素、乙烯、细胞分裂素、赤霉素、脱落酸和其它植物生长调节物质在不定根形成中的作用,并讨论了它们之间的相互关系.     

Enzyme Changes in Relation to Cell Growth in Excised Root Tissues1

Serial sections 10 mm. in length taken from the tip towardsthe base of the bean root have been cultured on 2 per cent,sucrose. At various time-intervals, length, invertase, phosphatase,and protein content of the sections have been determined. Alterationsin the enzyme complement of the sections have been related togrowth and protein content. The relation of changes occurringin excised fragments to those in the intact root have been discussed.     

Some Biochemical Changes Associated with Paclobutrazol-Induced Adventitious Root Formation on Bean Hypocotyl Cuttings

Phaseolus vulgaris hypocotyl cuttings were placed in solutionscontaining either 0 (controls) or 43 µM paclobutrazolfor 24 h after which they were placed in peat– perlitefor 8 d. Paclobutrazol more than doubled the number of rootsformed on the cuttings but did not affect individual root length.Compared with controls, treated cuttings exhibited increasedactivities of catalase, peroxidase, polyphenol oxidase, malatedehydrogenase, protease and RNase in the base of the cuttings.These enhanced enzyme activities were particularly evident between3 and 5 d after excision. The largest paclobutrazol-inducedpromotion of enzyme activity occurred with malate dehydrogenasewhich was increased more than 2-fold compared with the controls.In contrast, paclobutrazol reduced amylase activity in comparisonto controls, suggesting that this enzyme may not be directlyrelated to root formation. These data indicate that the enhancementof adventitious root formation by paclobutrazol is accompaniedby changes in the activities of a number of enzymes which havepreviously been postulated to be involved in rooting. However,these changes in activity are generally greatest later in therooting period, suggesting that they may be involved in thedevelopment rather than the initiation of roots. Enzyme activity, growth regulator, Phaseolus vulgaris L., rooting     

The Role of Benzyladenine in the Differentiation of Tracheary Elements in Jerusalem Artichoke Tuber Explants Cultured in vitro

The role of benzyladenine (BA) in the differentiation of trachearyelements in Jerusalem artichoke (Helianthus tuberosus L.) tuberexplants was studied. For maximum differentiation of trachearyelements (25–30% of the cell population), treatment withoptimal concentrations of benzyladenine (5.0 mg dm^–3)in the presence of -naphthaleneacetic acid |NAA| (1.0 mg dm^–3)for the first 6 d was as effective as its continued presenceduring the entire 14 d period of study. A majority of the differentiatedtracheary element appeared between the 10th and 14th days ofculture. It was further observed that concentrations of activecytokinins in the tissue were considerably reduced within 2d after transfer from the BA-containing medium to a BA-freemedium. This was shown in three different ways: (1) monitoringthe amount of ethanol-soluble radioactivity at various timesafter transfer from |14C|-BA containing medium to BA-free medium;(2) bioassay of various cytokinin fractions from tissue extractseparated by thin layer chromatography; (3) indirect assay oftissue cytokinin activity through its interaction with abscisicacid for the promotion of auxin-induced cell division in thistissue. Both gibberellic acid (5.0 mg dm^–3) and abscisic acid(2–0 mg dm^–3) effectively inhibited the differentiationof tracheary elements even if provided after 6 d of pre-incubationin a high tracheid inducing medium. However, the appearanceof differentiated cells for the first 2 d after transfer wasnot significantly affected. A hypothetical scheme for the role of benzyladenine in the differentiationof tracheary elements in this tissue is discussed. It is suggestedthat during one or more critical cell divisions in the presenceof optimal levels of benzyladenine, a proportion of cells areinduced or committed for later differentiation into trachearyelements. The high concentrations of benzyladenine requiredduring induction are not needed during the intervening celldivisions, nor for the actual differentiation of the trachearyelements. Key words: Tracheary element differentiation, Jerusalem artichoke (Heliantlus tuberosus), Benzyladenine, Gibberellic acid, Abscisic acid