The intersectional hybrid between Weigela hortensis and W. maximowiczii (Caprifoliaceae)

Morphologically intermediate plants between Weigela hortensis (Siebold & Zucc.) K.Koch and W. maximowiczii (S.Moore) Rehder have been found in Miyagi and Yamagata Pref., northern Japan. Quantitative character analyses of flowers, pollen stainability and molecular analyses indicated that the intermediate plants were hybrids of those two species. This is the first record of an intersectional hybrid with W. maximowiczii (sect. Weigelastrum ) as one of the parent species. The morphological differences among hybrid individuals imply the possibility of backcrosses or formation of second or later generations of hybrids, although those may be quite rare because of a low frequency of viable pollen grains. Causes of hybridization between two distantly-related species in Weigela are discussed. © 2002 The Linnean Society of London, Botanical Journal of the Linnean Society , 2002, 138 , 369–380.     

Effects of chloride ion on HILL reactions in Euglena chloroplasts

Effects of Cl^– and other anions on the rate of HILL reactionin Euglena chloroplasts were investigated. Cl^– acceleratedthe reaction rate with ferricyanide as HILL oxidant; Br^–,F^– and I^– were also effective; NO₃^–, PO₄^2–and SO₄^2– were less effective. Divalent cations, Ca²⁺and Mg²⁺, were also highly effective. The promoting effectsof these ions were highly dependent on pH and the nature andconcentration of the HILL oxidant used. Accelerating effectsof the ion increased with decreasing concentrations of ferricyanide.Generally, the stimulating effect of Cl^– was much moremarked at pH 7–7.5, with little effect at pH 5. Thus,the pH-activity relationship in the HILL reaction is more orless markedly modified by addition of ions. Cl^–, and other anions, accelerated the reaction by affectingonly the dark rate-limiting portion of the HILL reaction; thelight reaction constant remained uninfluenced. We inferred thatsome reaction step, at which ferricyanide receives electronfrom photosystem 2, is accelerated by Cl^– and other ions.Cl^– effects were rather small, or undetectable, with DPIPor p-benzoquinone as oxidants. (Received January 8, 1970; )     

Aim‐then‐shoot anemotaxis involved in the hopping approach of potato tuberworm moth Phthorimaea operculella toward a sex pheromone source

Male moths locate conspecific females by pheromone‐induced upwind flight maintained by detecting a visual flow, termed optomotor anemotaxis. Their behavioural pattern is characterized by an upwind surge in response to a pheromone stimulus and crosswind casting after odour loss, which is considered to be reset and restarted on receipt of another pheromone pulse. However, pheromone‐stimulated males of the potato tuberworm moth Phthorimaea operculella exhibit a series of short and straight intermittent flights, or hops, when moving upwind. It is unclear whether they navigate by employing the same behavioural pattern and wind detection mechanism as that used by flying moths. To analyze odour‐modulated anemotaxis in male potato tuberworm moths, a flat wind tunnel is constructed to give regular odour stimuli to an insect regardless of its location. Moths are subjected to pheromone pulses of different frequencies to test whether they show a behavioural pattern that is reset and restarted by a pheromone pulse. Moths on the ground are also subjected to crosswind shear to examine their detection of wind direction. Path analyses reveal that males surge upwind when they receive a pheromone pulse and exhibit casting by successive hops when they lose odour. This behavioural pattern appears to be similar to that of flying moths. When the direction of the airflow is switched orthogonally, males adjust their course angle accordingly when they are on the ground. It is suggested that, instead of optomotor anemotaxis, this ‘aim‐then‐shoot’ system aids the detection of wind direction, possibly by mechanosensory means.     

SYNCHRONIZATION OF BUDDING CYCLE IN YEAST CELLS, AND EFFECT OF CARBON MONOXIDE AND NITROGEN-DEFICIENCY ON THE SYNCHRONY

1. A procedure was devised to synchronize the budding cycleof baker's yeast. The method consists of preliminary selectionof the cells by differential centrifugation, combined with treatmentat 40° for 1 hr. On further incubation of the pre-treatedcells in the fresh medium at 27°, a synchronized buddingof the whole population occurs. followed by equally well synchronizedmaturation and separation of the buds formed. 2. The effect of CO on the budding cycle was investigated byintroducing the gas at various stages of the cycle. The mostmarked effect was observed when it was introduced in the inductionperiod of the cycle, resulting in a prolongation of the inductionperiod. Anaerobiosis was found to cause inhibition similar tothat caused by CO described above. 3. 2, 4-Dinitrophenol, when added at the beginning of the inductionperiod, at a low concentration (1.8x 10^–4M), was foundnot to abolish the first budding, but to prolong bud-maturationmarkedly. At higher concentrations of the poison, the firstbudding was markedly retarded, followed by the suppression ofbud-maturation. The budding was completely suppressed at l.8x10^–3M of the poison. 4. The absence of N-source in the incubation medium did notsignificantly affect the first budding, but completely abolishedthe capacity of the cells (both mothers and daughters) for thesecond budding. The lost capacity could be recovered by supplementingthe deficient medium with an N-source (urea), but when the timingof the supply was delayed, the recovery became less and lesssatisfactory. The presence of CO in the gas atmosphere was foundto enhance the deleterious effect of N-deficiency. (Received September 2, 1961; )     

Ferricyanide-induced absorbance change of carotenoid in chromatophores of Rhodopseudomonas spheroides correlated to the oxidation of bacteriochlorophyll 885

Addition of high concentrations (e.g., 1–100 mM) of ferricyanideto a chromatophorc suspension of Rhodopseudomonas spheroidescaused a change in the absorption spectrum of carotenoid (spheroidene),which was completely reversed by adding reducing reagents suchas ferrocyanide and ascorbate. The spectral change is representedby a shift in the absorption spectrum of carotenoid by 2 to2.5 nm towards the longer wavelength side. The presence of piericidinA, o-phenanthroline or Cl-CCP in the reaction mixture did notaffect the ferricyanide-induced absorbance change. Triton X-100markedly suppressed the magnitude of the change. The additionof ferricyanide also caused simultaneous absorbance changeswith maxima at 590 and 885 nm. These are ascribed to oxidationof the (bulk) bacteriochlorophyll, BChl 885. There was no absorptionchange at other peaks of bacteriochlorophyll in the infraredregion (i.e., 800 and 855 nm). Therefore, the ferricyanide-inducedabsorbance change of carotenoid did not represent an oxidation-reductionreaction of carotenoid but was intimately correlated with oxidationof BChl 885 in the chromatophores, as judged from similaritiesobserved with respect to the time course patterns, midpointpotential (545–555 mv) in the ferriferrocyanide reactionsystem, as well as behavior towards various reagents and inhibitorsadded. A similar change of carotenoid (i.e., 2–2.5 nmshift of absorption spectrum) was caused by addition of MgCl₂to the chromatophores, but this did not induce any change inthe absorption spectrum of bacteriochlorophyll. The nature ofthe spectral change of carotenoid in chromatophores is discussed. (Received April 16, 1970; )     

Change in the indole-3-acetic acid oxidase level in leaves of Begonia evansiana cuttings at the time of aerial tuber formation under short-day conditions

IAA oxidase in Begonia evansiana leaves was partially purifiedby DEAE cellulose chromatography. The enzyme was identifiedas peroxidase from its elution pattern, its Michaelis constantand the effects of various inhibitors and high temperature. In B. evansiana, which requires SD treatment to form aerialtubers, the amount of IAA oxidase in leaves increased to a maximumafter 2 days of SD treatment. When SDs with interrupted nightwere given, a maximum was reached after 6 SDs. Thus, the changein IAA oxidase content had an inverse correlation to that forIAA content observed previously. (Received May 18, 1970; )     

Light-induced absorption spectrum changes of carotenoid in chromatophores of photosynthetic bacterium, Rhodopseudomonas spheroides II. Rapid and slow absorption changes of carotenoid in chromatophores

Time courses of light-induced absorption changes of carotenoid(spheroidene) in chromatophores of the photosynthetic bacterium,Rhodopseudomonas spheroides, consisting of an 8–10 nm-shiftin the carotenoid absorption spectrum towards the longer wavelength,were investigated. The whole time course of absorption changecan be expressed as the sum of two first order reactions; arapid change accomplished in several msec after the onset ofillumination with actinic light (800–900 nm) and a slowchange extending over the whole period (200 msec). The rapidchange required a high light intensity, whereas the slow changewas saturated at relatively low light intensity (ca. 5xl0³ erg/cm²sec). Electron transport inhibitors (HOQNO, piericidin A and o-phenanthroline)and Cl-CCP, at concentrations uncoupling photophosphorylation(10^–M), inhibited slow change but did not affect rapidchange. The rapid change was inhibited by higher concentrationsof Cl-CCP (10–4 M) and by o-phenanthroline in the concomitantpresence of an uncoupling concentration of Cl-CCP. The rapidand slow changes have midpoint potentials of 440 and 420 mv,respectively; as calculated from absorption changes in the presenceof ferri- and ferrocyanide mixtures. Relationships between absorptionspectrum changes and other reactions in the chromatophores wereanalyzed. Slow absorption change is closely related to the highenergy intermediate, or state, of photophosphorylation. Rapidabsorption change, with a midpoint potential of 440 mv, is relatedto the electron flow mediated by P870; although it does notdirectly reflect the state of P870, itself. ¹ This article is the second of a series published under thesame title in this journal, volume 11 (1970) p. 519–530. ² Present address: Department of Biology, Faculty of Science,Toho University, Narashino City, Chiba 275, Japan. (Received October 30, 1970; )     

Comparison of carbon dioxide fixation and the fine structure in various assimilatory tissues of Amaranthus retroflexus L

The pattern for primary products of CO₂-fixation and the chloroplaststructure of Amaranthus retrqflexus L., a species which incorporatescarbon dioxide into C₄ dicarboxylic acids as the primary productof photosynthesis, were compared in various chlorophyll containingtissues,i.e., foliage leaves, stems, cotyledons and pale-greencallus induced from stem pith. Despite some morphological differencesin these assimilatory tissues, malate and aspartate were identifiedas the major compounds labelled during a 10 sec fixation of¹⁴CO₂ in all tissues. Whereas, aspartate was the major componentin C₄-dicarboxylic acids formed in foliage leaves, malate predominatedas the primary product in stems, cotyledons and the pale-greencallus. The percentage of ¹⁴C-radioactivity incorporated intoPGA and sugar-P esters increased and ¹⁴C-sucrose was detectedin the prolonged fixation of ¹⁴CO₂ in the light, not only infoliage leaves, but also in stems and cotyledons. ¹ This work was supported by a Grant for Scientific ResearchNo. 58813, from the Ministry of Education, Japan. ² Present address: Institute of Applied Microbiology, Universityof Tokyo, Tokyo, Japan. ³ Present address: Department of Biochemistry, University ofGeorgia, Athens 30601. Georgia, U. S. A. (Received July 10, 1971; )