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.     

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.     

光合作用系统II外周蛋白——P23k去折叠的热力学和动力学

利用荧光光谱学等方法结合高压力技术研究了光合作用系统II中的一个外周蛋白——— 2 3kD(以P2 3k表示 )蛋白的去折叠。热力学研究表明 ,在 2 0℃、180MPa(1MPa =10 .0大气压 )可使该蛋白质完全去折叠 ,而在3℃ ,16 0MPa即可使该蛋白质完全去折叠 ,这是迄今为止有关研究中最易被高压力去折叠的一个蛋白质。在2 0℃ ,该蛋白质在常压下去折叠反应的标准自由能与标准体积变化分别为 2 3.4 5kJ mol和 - 15 0 .3ml mol;动力学研究揭示该蛋白质的折叠反应的活化体积ΔV f 为正值 (84 .1ml mol) ,而去折叠反应的活化体积ΔV u 为负值(- 6 6 .2ml mol)。在常压下 ,折叠和去折叠反应的速度常数 (K0f,K0u)分别为 1.87s- 1 和 1.3× 10 - 4s- 1 ,这些结果为解释该蛋白质易被压力去折叠提供了线索     

Increase in Shedding of Intercellular Adhesion Molecule-1 in Human Malignant Melanoma Cell Lines Treated With Hyperthermia In Vitro

Human malignant melanoma cell lines were found to increase shedding of soluble intercellular adhesion molecule-1 (sICAM-1) into the culture medium when the cells were treated with hyperthermia at 41–43°C for 3–6 hr in vitro. The content of ICAM-1 in the cell lysate was also found to be increased after hyperthermia. The increased rate of ICAM-1 concentration in the cells was at maximum when they were incubated at 41°C for 3 hr. Also, the melanoma cell lines heat-treated at 41°C showed more intense immuno-fluorescence in the ICAM-1 expression on the cell surface. It remains to be investigated further whether the effects of hyperthermia on the ICAM-1 expression in melanoma cells is to augment membrane ICAM-1 expression, which in turn leads to shedding of soluble ICAM-1 or only to acceleration of shedding of sICAM-1 by unknown mechanisms.     

Sex Allocation Ratio in a Wind-Pollinated Self-Incompatible Monoecious Tree, Alnus firma Sieb. et Zucc. (Betulaceae)

Abstract Biomass sex allocation of Alnus firma , a wind-pollinated self-incompatible monoecious tree species, was directly measured at the inflorescence (prezygotic) stage. Sex allocation ratio at the fruit stage was estimated from the number of female inflorescences, percent fruit production, and the mean dry weight of a female inflorescence and a fruit catkin. Investment in male function far exceeds that in female function at the prezygotic stage. When the costs of fruit catkins and seeds were included in the estimation of female function, then the sex allocation bias was reversed towards female. Intrapopulational variation of the sex allocation ratio with respect to tree height and size was also investigated. A strong negative correlation was observed in both cases, although a positive relationship has been predicted by theorists and some previous empirical data have supported this prediction.     

Interclonal differences, plasticity and trade-offs of life history traits of Cyperus esculentus in relation to water availability

Cyperus esculentus is an exotic clonal (or pseudoannual) weed in Japan, and its range is steadily increasing. To investigate its interclonal variation and phenotypic plasticity in response to water availability, five clones of C. esculentus , collected from different sites in Japan, were grown singly in pots placed outdoors under dry and wet conditions. All the traits examined showed considerable variation among the five clones. However, two clones from Tochigi were similar to each other; thus, they might have originated from the same founder population. The clone from Ibaraki was quite different from the others. Therefore, it is suggested that the Japanese populations of C. esculentus might have resulted from multiple introductions of genotypes from geographically separated and, hence, genetically differentiated, source populations. All the clones also showed considerable plasticity in response to water availability. Clones with a larger ramet number had a greater plasticity, whereas tuber size was invariant across water treatments. Highly plastic traits had generally low interclonal variation in plasticity. All the clones had high productivity and produced more ramets and tubers under wet conditions than under dry conditions. Moreover, water availability could partially regulate the mode of its reproduction; wet conditions favored tuber production (vegetative propagation) while dry conditions favored sexual reproduction. A number of trade-offs occurred between the traits of clonal growth, storage and sexual reproduction, indicating that allocation among the competing functions/organs is mutually exclusive in plants. The results obtained here suggest that C. esculentus is more likely to invade wet habitats than dry habitats.     

Mechanisms of Central Die-back of Reynoutria japonica in the Volcanic Desert on Mt. Fuji. A Stochastic Model Analysis of Rhizome Growth

Reynoutria japonica (Polygonaceae) is a pioneer clonal herbcolonising the volcanic desert on Mt. Fuji (height 3776 m),central Japan; establishment of secondary successional speciesoccurs only in the central die-back parts of the clonal standsofR. japonica. Clonal stands were excavated and the morphologyand growth pattern of the rhizomes were investigated with specialreference to the mechanisms of central die-back. Four morphologicalparameters, length of mother rhizomes, and number, branchingpositions and branching angle of daughter rhizomes on respectivemother rhizomes were measured or counted, and their roles inrhizome growth were examined employing a stochastic computersimulation model of the whole stand development. The simulationsclarified that, of these four parameters, the branching anglewas the most influential determinant of the whole pattern ofshoot distribution and that the central die-back was producedwhen the mean branching angle was 40° or smaller. Theseresults strongly infer that the onset of central die-back iscaused intrinsically byR. japonica itself by having the meanbranching angle of 40°. The adaptive significance of thegrowth pattern is discussed in relation to resource acquiringand habitat exploitation strategies of this species. Below-ground morphology; branching angle; central die-back; clonal plant; computer simulation; Japanese knotweed;Reynoutria japonica Houttuyn; rhizome growth pattern     

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; )     

STUDIES ON THE FORMATION AND SPROUTING OF AERIAL TUBERS IN BEGONIA EVANSIANA ANDR. IX. EFFECTS OF TEMPERATURE ON TUBER INITIATION

The effects of temperature on the aerial tuber initiation ofBegonia evansiana Andr. in response to short-day condition wereinvestigated. Tuberization was inhibited by relatively low and high temperaturesduring the dark periods. The optimal nycto-temperature was 23°and hardly changed by not only photo-temperature but also daylength.There were two temperature-sensitive phases in the dark period;one came at its beginning, and the other later one came at varioustimes depending on the length of the light period. Low temperatureswere effective at both of these sensitive phases, but high temperatureshad an influence only at the later one. Photo-temperatures exerted little influence on tuberizationunder the sub-optimal daylength, but the lower temperatureswere promotive under longer daylengths. (Received August 2, 1963; )