Effect of malformin on root growth

Malformin induces curvatures, stimulates root hair and lateralroot formation, promotes radial expansion, inhibits elongation,wet and dry weight, cell division and cell wall synthesis inroots of Zea mays, but has no effect on protein synthesis. Thegrowth curves (elongation, wet and dry weight) of Z. mays rootstreated with malformin are cubic. Processes which are involvedin inhibition of elongation are considered the primary causeof root curvatures by malformin. ¹This research was supported by grant GB-7158 from the NationalScience Foundation and grant E-146-F from the American CancerSociety. Journal Paper No. 3536 of the Purdue Agricultural ExperimentStation. ²Present address: Volcani Institute of Agricultural Research,P.O.B. 6, Bet-Dagan, Israel. (Received December 24, 1969; )     

Sodium Requirement of Monocotyledonous C4 Plants for Growth and Nitrate Reductase Activity

The effects of Na application on growth and nitrate reductaseactivity of seven C₄ plant species, Zea mays, Echinochloa crus-galli,Panicum miliaceum, Panicum coloratum, Panicum dichotomiflorum,Panicum maximum and Chloris gayana were studied. Except forZ. mays and P. miliaceum, Na application enhanced growth significantly,and concurrent increases in nitrate reductase activities weredetected in Panicum coloratum, Panicum dichotomiflorum, Panicummaximum and Chloris gayana. ¹Present address: International Research Institute, Ciba GeigyJapan Ltd., Takarazuka, Hyogo 665, Japan. ²Present address: Photobiology Lab., Research Institute forFood Science, Kyoto Univ., Uji, Kyoto 611, Japan. (Received May 2, 1988; Accepted August 22, 1988)     

Trifluralin and root growth

Trifluralin inhibited root elongation and induced root tip swellingof Zea mays and Triticum aeslivum. Time-course experiments showedthese effects occurred within 6 hr of treatment. As the rootstreated with trifluralin enlarged, there was a concomitant increasein root growth inhibition. Bioassays were devised to quantitativelymeasure the radial enlargement of trifluralin-treated roots.Histological observations indicated that swollen root tissuewas growing in a non-polar manner. The root swelling effectof trifluralin was inhibited 70% by the reducing agent, 2,3-dimercaptopropanol.Trifluralin had no effect on SH content of root tip proteinof Z.mays. ¹ Published with the approval of the Director of die West VirginiaAgricultural Experiment Station as Scientific paper No. 1177. ² Present address: Department of Biology, Mercyhurst College,Erie, Pennsylvania 16501, U.S.A. (Received March 19, 1971; )     

Effect of a Growth Inhibitor on the Hydroxyproline Level in Cell Wall of Zea Primary Roots

Evidence supporting the view that there is an inverse relationshipbetween the hydroxyproline-protein level in the cell wall andthe ability of a cell to undergo rapid cell elongation was obtained.A growth inhibitor extracted from Zea primary roots acceleratedthe incorporation of radioactivity derived from ¹⁴C-prolineinto the sodium lauryl sulfate (SLS)-insoluble cell wall fraction.However, the inhibitor had no effect on the ratio of hydroxyprolineto proline that was incorporated into the SLS-insoluble fraction. We have discussed what this growth inhibitor may mean in thegeotropic curvature of Zea primary roots. ¹ Present address: Faculty of Education, University of Yamagata,Yamagata 990, Japan (Received May 9, 1981; Accepted August 8, 1981)     

Effects of Exogenous Auxin on the Regulation of Elongation Growth of Excised Segments of Vigna Hypocotyls under Osmotic Stress

IAA applied simultaneously with osmotica greatly enhanced theadaptive recovery of the elongation growth of segments of Vignahypocotyls during osmotic stress irrespective of whether ornot absorbable solutes were present. IAA stimulated both thesurface pump and the xylem pump, which have been shown to bestimulated by osmotic stress and to control the yielding ofthe cell wall and the absorption of solutes. Thus, wall extensibilityand the effective turgor were further enhanced under osmoticstress in the presence of IAA. These results indicate that thesimultaneous presence of IAA can reduce the inhibition of growthby osmotic stress, and they support numerical predictions basedon the apoplast canal model. The mechanism involved in the rapidrecovery of growth is discussed. ¹ Present address: Research Centre, Guangxi Agricultural University,Xiu Ling Rd., Nanning, Guangxi 530005 China. ² Present address: Biology Institute, Department of GeneralEducation, Nagoya University, 1 Furo-cho, Chikusa-ku, Nagoya,464 Japan. ³ Present address: Graduate School of Integrated Science, YokohamaCity University, 22-2, Seto, Kanazawa-ku, Yokohama, 236 Japan.     

Auxin- and Acid-Induced Changes in the Mechanical Properties of the Cell Wall

Auxin- and acid-induced changes in the mechanical propertiesof the cell wall were analyzed by measuring the creep of thecell wall using pumpkin (Cucurbita moschata Duch cv. Shirakikuza)hypocotyl segments. Hypocotyl segments were treated with orwithout IAA and stored in 50% glycerol at –15°C formore than 2 weeks before measurements. Creep rate increasedwith the increase in the load. The increase was first very slowup to the phase shift point (yield threshold, y), and afterthat, it was steep. The rate of the creep rate increase (creepcoefficient, Cm) was larger and y was smaller at pH 4.5 thanpH 6.8. This indicates cell wall loosening was facilitated underacidic conditions. IAA-pretreatment of the segments resultedin the lowering of y at pH 6.8 only. Around pH 5 and 45°C,Cm was highest and y was lowest. Boiling in distilled wateralmost lost the differential effect of Cm and y on pH and IAA.The differential effect of pH on Cm and y were recovered bythe addition of a crude extract of cell wall-bound proteins.It is implied that some enzymatic processes are involved inthe control of acid-induced cell wall extension. ¹Present address: Nihon Shokuhin Kako Co., Ltd. 30 Tajima, Fuji-City,Shizuoka, 417-8530 Japan. ²Present address: Graduate School of Environmental Earth Science,Hokkaido University, Sapporo, 060 Japan.     

Auxin Changes Both the Extensibility and the Yield Threshold of the Cell Wall of Vigna Hypocotyls

Elongation of plant stem is governed by two simultaneous processes:irreversible yielding of the cell wall and uptake of water.Among many candidates for the parameters that regulate and/or restrict growth, we focused on the mechanical propertiesof the cell wall and determined those parameters that governthe process of IAA-induced growth by means of the pressure-jumpmethod combined with the pressure-probe technique. The elongation growth of segments excised from the elongationzone of Vigna hypocotyls was accelerated by xylem perfusionwith 10^–4 M IAA. During the promotion of growth, boththe extensibility () of the cell wall and the effective turgor(Pⁱ–Y) increased while only a little or no change in theintracellular pressure (Pⁱ) occurred. These results indicate that IAA increases not only the extensibilityof the cell wall but also the effective turgor, i.e., the drivingforce for yielding of the cell wall. However, the driving forceis not increased by the increase in Pⁱ but by the decrease inthe yield threshold (Y). These results suggest that Y is adjustableduring the regulation of growth. ¹Present address: Department of Biology, Faculty of Science,Okayama University, Okayama, 700 Japan (Received September 20, 1990; Accepted November 27, 1990)     

Amarinin: A New Growth Inhibitor from Luffa amara

A growth inhibitor, amarinin was isolated from the seeds ofLuffa amara. Its formula has been established as 2-deoxy cucurbitacinB by spectrometric analysis coupled with chemical degradation.Amarinin inhibited the growth of the second leaf sheath of riceboth in the absence and presence of GA₃. ¹Present address: Department of Chemistry, Arambag College,P.O. Arambag, Hooghly, West Bengal, India ²Present address: Department of Chemistry, Calcutta University,92, A.P.C. Road, Calcutta 700 009 (Received March 15, 1985; Accepted May 1, 1986)     

Does ethylene induce elongation of the rice coleoptile through auxin?

Ethylene stimulated the elongation of intact rice (Oryza sativaL.) coleoptiles in which endogenous growth had been stoppedcompletely by decapitation and red light. p-Chlorophenoxyisobutyricacid slightly inhibited endogenous growth, but not the ethyleneinduced growth. Thus, ethylene could stimulate the elongationof coleoptiles in which the auxin level was considered to bevery low. ¹ Present address: Institute for Agricultural Research, TohokuUniversity, Katahira, Sendai 980, Japan. (Received February 16, 1979; )     

HORMONAL CONTROL OF ROOT GROWTH I

The growth of the primary root of a single gene dwarf mutantof Zea mays L., dwarf-1, is dependent upon gibberellic acidor one of its derivatives as a growth hormone. Moreover, forthe root to respond to gibberellin treatment both embryonicand mature tissues must contribute growth stimuli. ¹ This study was financed by the National Institute of Health,Grant GM 08706-03.     

Activation Energies of Reactions Catalyzed by the Nitrate Reductase from Chlorella vulgaris

The thermal dependence of two of the reactions catalyzed bythe nitrate reductase from Chlorella vulgaris was determined.The activation energies for NADH:nitrate oxidoreductase (EC1.6.6.1 [EC] ) and NADH:Cytochrome c oxidoreductase (EC 1.6.99.3 [EC] )are 42.1 kJ?mol^–1 and 21.5 kJ?mol^–1, respectively.Since the thermal dependency of the two enzymes is different,ratios of the activities will vary with temperature. The importanceof both rigorous thermal control during nitrate reductase assaysas well as the need to specify the temperature at which theratio of activities for the enzyme are clearly established. ¹Present Address: Cropping Systems Research Laboratory, USDA-ARS,Route 3, Box 215, Lubbock, TX 79401, U.S.A. (Received November 25, 1987; Accepted March 2, 1988)     

PHOSPHOGLUCOMUTASE ALLOZYME EVIDENCE FOR AN OUTCROSSING MODE OF REPRODUCTION IN THE HERMAPHRODITIC BROODING BIVALVE MYSELLA TUMIDA (GALEOMMATACEA)

Allozyme variation of a Mysella tumida population in PatriciaBay, B.C., Canada was investigated at the phosphoglucomutase(PGM) locus. Seven alleles were detected. The observed frequencyof allelic combinations did not differ significantly from randommating expectations (0.25 < P < 0.50), however, heterozygositylevels were slightly greater than expected (Selander's D = 0.022).These results, together with previous work on the M. tumidareproductive cycle, indicate that natural populations of thisbivalve rarely, if ever, self-fertilize. ^*Present Address: Friday Harbor Laboratories, University ofWashington, Friday Harbor, WA 98250, U.S.A. ^**Present Address: Museum of Zoology, University of Michigan,Ann Arbor, M1 48109, U.S.A. (Received 30 December 1986;     

Suppression of Acid Invertase Activity by Antisense RNA Modifies the Sugar Composition of Tomato Fruit

cDNA for an acid invertase (EC 3.2.1.26 [EC] ) of tomato (Lycopersiconesculentum Mill.) fruit was introduced into tomato plants underthe control of the cauliflower mosaic virus 35S promoter inthe antisense orientation. The antisense gene effectively suppressedthe invertase activity in soluble and cell wall fractions fromripening fruits. The sucrose content of fruits of the transformantswas markedly increased, while the hexose content was reduced.These results indicate that acid invertase is one of main determinantsof the sugar composition of tomato fruit. The invertase activityin the cell wall fraction of the leaf tissues of the transformantswas not suppressed to the same extent as that in the solublefraction. Wounding of the control leaf tissues induced invertaseactivity in both soluble and cell wall fractions. The inductionof activity in the soluble fraction was suppressed by the antisensegene, while that in the cell wall fraction was unaffected. Thesefindings suggest that mRNA for some other invertase, in particular,the mRNA for a cell wall-bound invertase, was present in leaves. ¹Present address: Plant Breeding and Genetics Research Laboratory,Japan Tobacco Inc., 700 Higashibara, Toyoda, Iwata, Shizuoka,438 Japan. ²Present address: National Institute of Agrobiological Resources,Kannondai, Tsukuba, Ibaraki, 305 Japan.     

Orientation of Microtubules during Regeneration of Cell Wall in Selected Giant Marine Algae

The microtubules in highly synchronized aplanospores of twogiant marine algae, Boergesenia forbesii and Valonia ventricosa,were examined by immunofluorescence microscopy throughout theregeneration of the cell wall. Microtubule orientation was alwaysrandom up to 20 h after wounding, although the orientation ofcellulose microfibrils changed from random to parallel withinthat time period. When the rhizoid cells were in the stage ofelongation at 7 to 10 days after wounding, highly ordered microtubuleswere always observed along the longitudinal cell axis exceptat the very tip of the cells where random ones were found. Incontrast, the microfibrils in the innermost lamellae of newlysynthesized cell walls showed three different orientations,that is, transverse, longitudinal and oblique to the longitudinalcell axis. These observations suggest that microtubules maycontrol cell shape, but not the orientation of microfibrils.The mechanism of cell wall construction in these algae is discussedin relation to the self-assembly mechanism thought to operatein the construction of helicoidal cell walls. ³ Present address: Polymer Research Laboratory, Mitsui ToatsuChemicals, Inc., Yokohama, Kanagawa 244, Japan. (Received November 18, 1987; Accepted April 11, 1988)     

Effects of a Very Low Magnetic Field on the Gravitropic Curvature of Zea Roots

Caryopses with horizontally oriented primary roots of Zea maysL. (cv. Golden Cross Bantam 70), exposed to light, were incubatedin magnetic fields of 50 µ gauss or 0.5 gauss (control)for 12 h. The gravitropic curvature of roots incubated in afield of 50 µ gauss was 37% larger than the control value,while the control roots grew more rapidly. ¹ Present address: Biology Laboratory, Faculty of Education,Yamagata University, Yamagata, 990 Japan (Received December 25, 1989; Accepted March 19, 1990)     

The Deduced Amino Acid Sequence of Phytochrome from Adiantum Includes Consensus Motifs Present in Phytochrome B from Seed Plants

A cDNA for the phytochrome of the fern Adiantum capillus-venerisL. was cloned and sequenced. The deduced phytochrome is 50{smalltilde}55% identical to phytochromes of seed plants, and 68%identical to Selaginella phytochrome. Regions resemble thosein previously characterized phytochromes from ferns, lower plantsand seed plants. ³Present address: Yamanouchi Pharmaceutical Co., Ltd., 21 Miyukigaoka,Tsukuba-shi, Ibaraki, 305 Japan ⁴Present address: Plant Growth Regulation Laboratory, The Instituteof Physical and Chemical Research (RIKEN), Hirosawa 2-1, Wako-shi,Saitama, 351-01 Japan ⁵Present address: Advanced Research Laboratory, Hitachi, Ltd.,Hatoyama, Saitama, 350-03 Japan     

High Affinity of the 5'-Upstream Region of a Winged Bean Chymotrypsin Inhibitor Gene for Nuclear Matrix

The 5'-upstream region of a winged bean chymotrypsin inhibitorgene (WCI-3b) was found to have a high affinity for nuclearmatrix. The region, named WCI-3b MAR (matrix attachment region),is highly A+T-rich and contains multiple sites interacting withnuclear matrix. A MAR was also found in the corresponding regionof the WCI-x gene, another active gene of the WCI family. SeveralMAR-binding proteins were detected in the wheat nuclear matrix. ⁴Present address: Friedrich Miescher Institute, P.O. Box 2543,CH-4002 Basel, Switzerland. ⁵Present address: Research Institute for Biological Sciences(RIBS), Kayo-cho, Jyobo-gun, Okayama, 716–1241 Japan.     

A Method for the Rapid Growth in Culture of Gametophytes of Equisetum arvense with Antheridia

Rapid growth in culture of Equisetum arvense gametophytes wasobtained using Murashige-Skoog's medium plus 3% (w/v) sucroseand continuous illumination. In darkness, growth was reducedand chlorophyll synthesis markedly inhibited. Antheridia formedon the top margin of gametophytes in light and darkness butarchegonia were not observed in either case. ¹Present address: Interdisciplinary Research Institute of EnvironmentalSciences, Higashi-yanagi-cho, Nishi-iru, Shichihon-matsu, Itsutsuji-dori,Kamigyo-ku, Kyoto, 602 Japan. (Received June 5, 1989; Accepted September 12, 1989)     

Experimental evaluation of the avoidance reaction of Calanus finmarchicus

The avoidance reaction of Calanus finmarchicus copepodids wasobserved in the presence of quantifiable fluid mechanical signals.The experimental apparatus was a rotating cylinder of sea waterwith fixed obstacles (diameters 6 mm and 10 mm) which disturbedthe flow and stimulated avoidance. The experimental conditionsprevented unambiguous discrimination of signals; the amountand rate of fluid deformation appear to be the effective stimuli.Avoidance reactions began at a mean distance of 7 mm from thesmall obstacle and 6 mm from the large obstacle. Mean valuesfor fluid deformation for the small and large obstacles were0.12 and 0.24 mm/mm; fluid deformation rate values were 0.80and 1.0 sec^–1. There was less scatter for deformationvalues. The copepods preferentially avoided obstacles at anglesof about 60° with respect to the approach streamline. Avoidancespeeds averaged 16 cm.sec^–1; mean distance of avoidanceflights was 15 mm. ¹Contribution Number 4195 from the Woods Hole OceanographicInstitution. ²Present Address: Scripps Institution of Oceanography, La Jolla,California 92093. ³Present Address: Marathon Oil Company, Littleton, Colorado80160.     

GROWTH, MORTALITY, AND FEEDING RATES OF THE SNAIL HELIX ASPERSA AT DIFFERENT POPULATION DENSITIES IN THE LABORATORY, AND THE DEPRESSION OF ACTIVITY OF HELICID SNAILS BY OTHER INDIVIDUALS, OR THEIR MUCUS

When reared at high densities, young Helix aspersa show lessshell growth, even if waste products are removed. They alsofeed less, and show increased mortality. It is suggested thatthese effects are linked to reduced activity. Juveniles showreduced activity in the presence of adults or their mucus. Mucusof adult Cepaca nemoralis also depresses the activity of bothadult and young Helix and Cepaea. ^* Present Address: Unit Zoologi, Universiti Kebangsaan Malaysia,Jalan Pantai Baru, Kuala Lumpur, West Malaysia. (Received 12 May 1981;