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.     

TRANSPORT OF CATIONS FROM COTYLEDON TO SEEDLING OF THE EMBRYONIC PLANTS OF VIGNA SESQUIPEDALIS

Decrease of dry material, water, potassium and divalent cationsin the cotyledon (catabolic organ and accumulation of thesesubstances in the seedling (anabolic organ) were traced duringthe germination stage of Vigna sesquipedalis, cultured at 15°,25° and 30° in the dark on the sand with the supplyof tap water. One half of the divalent cations finally accumulatedin the seedling came from the root, whereas most of the potassiumfrom the cotyledon. Practically all the calcium in the cotyledonremained untransported, while 90% of K stored in the cotyledonwas transported into seedling. As for divalent cations otherthan Ca, 50–60% of the total divalent cations was transportable.The concentration of K, transportable dry material and transportabledivalent cations decreased linearly with the culture age. Fromthe temperature dependency of the rate of this decrease, itwas inferred that the transport of cations from cotyledon toseedling involved at least two component processes having activationenergies of approximately 5 and 16 Kcal, respectively. The rateof transport at 30° was found to be 10–20 times greaterthan that calculated from the simple diffusion model in water.Fractionation of cell inclusions in the cotyledon by the useof a centrifuge (1,500 and 16,000 rpm) suggested that the amountsof ions in the precipitable fractions, being bound to certaincell components, precisely corresponded to the untransportablefraction. ¹Main part of this work was reported at the Annual Meeting ofthe Botanical Society of Japan held at Fukuoka on Oct. 25. 1958. (Received October 16, 1961; )     

A new method in growth-electrophysiology: Pressurized intra-organ perfusion

Abstract A new experimental system was devised for the simultaneous measurement of elongation rate and the activity of the spatially separate electrogenic ion pumps of a hypocotyl segment excised from a seedling of Vigna unguiculata L. Walp. under enforced intra-organ perfusion by artificial solutions. The pathway of the perfusion medium was apoplastic space, including xylem vessels as main routes. The elongation rate of the segment was highly dependent on the perfusion pressure applied. It was possible to increase the growth rate under pressurized perfusion by 10-30 times as much as that without perfusion. Elongation rate was also dependent on respiration under perfusion, being retarded reversibly by anoxia a few minutes after the activities of the electrogenic ion pumps were stopped. Perfusion pressure had a little influence on the membrane potential (V_px) below a breakdown level (c. 130 kPa). Perfusion of mannitol or sorbitol solution of appropriate concentration reduced the elongation rate reversibly.     

Morphological variation in relation to flower use in bumblebees

To understand resource partitioning in a bumblebee community, we analyzed various morphological characters. A total of 1269 individuals of six bumblebee species, Bombus ardens, B. hypocrita, B. diversus, B. ignitus, B. honshuensis and B. beaticola, were examined and principal component analysis showed that the bumblebee species were clearly differentiated. Glossa, prementa and head lengths were positively correlated with the second component, and a longer proboscis was associated with a narrower body, which may help bees to intrude into and access deep‐lying nectar sources. Bombus diversus, with a long proboscis and narrow body, preferred flowers with a long corolla tube, whereas B. hypocrita and B. ignitus, which have short proboscises and wide bodies, visited flowers with short corollas or dish‐shaped flowers. Two pairs of consubgeneric species that have similar morphological characteristics, B. ardens and B. beaticola, and B. hypocrita and B. ignitus, divided flower resources by habitat selection and seasonal partitioning. For resource partitioning among bumblebee species, not only morphology but also other factors, such as habitat and seasonal preference, flower use, foraging behavior, and interspecific interactions, are responsible.     

Extensive size homoplasy at a microsatellite locus in the Japanese bumblebee, Bombus diversus

An extensive size homoplasy was found at microsatellite locus B11 of the bumblebee, Bombus diversus, in northern to central Honshu, Japan. A total of 16 alleles of different nucleotide sequences in five length morphs was obtained at B11 for this species. Of these alleles, five were 141 base pairs (bp) in length, five were 137 bp and four were 133 bp. Allele diversity in each length morph was high compared with previous studies. It is noteworthy that this extensive size homoplasy was found in a relatively small geographic area, in contrast to results from previous studies. Reconstruction of a median‐joining network revealed the complicated evolutionary process of the locus, involving insertion/deletion and point mutations. Preliminary estimation of the mutation rate of the B11 locus in B. diversus gives a value comparable to those estimated from experimental Drosophila populations. Effects of the extensive size homoplasy in population genetic studies is discussed.     

Spontaneous Membrane Potential Changes Associated With the Zooid and Vacuolar Contractions In Vorticella Convallaria

SYNOPSIS Interacellular membrane potential and spontaneous changes associated with motile responses in the zooid of Vorticella convallaria Linnaeus were recorded by conventional electrophysiological technics. an all-or-none large transient depolarization (large pulse) occurs in association with a spontaneous contraction of the zooid. A small transient potential change (small pulse) was observed in association with periodic contraction of the contractile vacuole.     

Effects of Benzyladenine on Chlorophyll, DNA, RNA and Protein Content of Attached Young Bean (Phaseolus vulgaris L.) Leaves

N⁶-Benzyladenine (BA) was applied to intact bean (Phaseolusvulgaris L.) primary leaves at 2 and 6 days after imbibition,when they were in the cell division and post-cell division stages,respectively. BA treatment at day 2 temporarily inhibited an increase in chlorophyllcontent in the following day, but stimulated it in later days.No such inhibition by BA was observed for changes with timein DNA, RNA, and protein content and f. wt. On the other hand,BA treatment at day 6 enhanced RNA and protein content, withoutsignificant influence on DNA and chlorophyll content and f.wt. The mode of cytokinin action on greening in leaves during cell-divisiongrowth seems to be different from that in etiolated cotyledons. Phaseolus vulgaris L., bean, greening, benzyladenine, DNA, RNA, protein