Rice yield enhancement by elevated CO2 is reduced in cool weather

The projected increase of atmospheric CO₂ concentration ([CO₂]) is expected to increase rice yield, but little is known of the effects of [CO₂] at low temperature, which is the major constraint to growing rice in cool climates. We grew rice under two levels of [CO₂] (ambient and elevated by 200 μmol mol^?1) and two nitrogen (N) fertilization regimes in northern Japan in 2003 (cool weather) and 2004 (warm weather) in the field in a free‐air CO₂ enrichment (FACE) system. Elevated [CO₂] significantly increased grain yield in both years in both N regimes, but the magnitude of the increase differed between years: 6% in 2003 vs. 17% in 2004, with a significant interaction between [CO₂] and year. This difference resulted from responses of spikelet number and ripening percentage to elevated [CO₂]. Enhancement of dry matter production and N uptake at heading by elevated [CO₂] was smaller in 2003 than in 2004, although at maturity there was no difference between years. No significant interaction between N regime and [CO₂] was detected in yield and yield components. The results suggest that yield gain due to elevated [CO₂] can be reduced by low temperature.     

Enhanced colour polymorphisms in island populations of the land snail Euhadra peliomphala

Variations in visible genetic polymorphisms are assumed to decrease in populations on small islands because of intense founder effects, genetic drift and inbreeding. However, we have found evidence of a marked enhancement of colour polymorphisms within populations on small oceanic islands that were colonized from the mainland. The source populations on the mainland of the land snail Euhadra peliomphala in four oceanic islands were estimated by phylogenetic analysis of mitochondrial DNA sequences. Diversity of shell colour was higher in the island populations than in the source populations on the mainland. In addition, the shell colour morphs differed not only among populations from different islands but also between the island populations and the source populations on the mainland. By contrast, no mtDNA variations were found in any of the island populations, even though the source populations possessed high mtDNA diversity. Thus, components of colour morphs changed in the island populations after their colonization, and colour polymorphisms are enhanced in these islands despite the loss of genetic variation. The above findings suggest that ecological mechanisms such as morphological release owing to a release from competition may overcome the tendency toward reduced genetic variation in islands to enhance the colour polymorphism.  © 2004 The Linnean Society of London, Biological Journal of the Linnean Society , 2004, 81 , 417–425.     

Immunological Relationships among Embryonic and Adult Chicken Pepsinogens: A Study with Monoclonal and Polyclonal Antibodies

To investigate the immunological relationships of pepsinogen isozymes present in embryonic and adult chicken proventriculi, we obtained monoclonal and polyclonal antibodies to these pepsinogens. Zymograms and immunoblots demonstrated that monoclonal antibody Y37 reacted with both embryonic and slow-migrating adult pepsinogens, while polyclonal antibodies against embryonic pepsinogen and fast-migrating adult pepsinogen were specific for these respective antigens. Shift from embryonic to adult-type pepsinogen occurred at about the time of hatching and the localizations of embryonic and adult-type pepsinogens within proventricular gland cells were found to differ by the indirect immunofluorescence method. Results with these antibodies revealed the immunological relations of these pepsinogens and the unique properties of embryonic chicken pepsinogen.     

Seasonal change in the respiration of the dobsonfly larva, Protohermes grandis(Megaloptera: Corydalidae)

SUMMARY 1. Seasonal change in the respiration of the dobsonfly larva, Protohermes grandis ,was studied by measuring the oxygen consumption rate (resting metabolism) bimonthly for 2 years. The respiratory rate of the larva was significantly lower during the summer season when the stream temperature rose to 30°C.
2. Summer depression of respiration was confirmed by measuring the rate of carbon dioxide evolution. The mean value of the respiratory quotient was estimated to be 0.76 ± 0.05 SE. The larva is believed to conserve energy by this reduction in respiratory rate,
3. In other seasons, however, the larva maintained a higher respiratory rate and remained active even in the winter when the stream temperature decreased near to 0°C. In fact, significant growth in weight occurred from mid-October to late March.
4. This acclimation to temperature may enable the efficient allocation of energy during the long larval period (3 years) in streams which have large annual fluctuations in temperature.     

Role of Penultimate Tyrosine in Haemoglobin β Subunit

The abnormalities of mutant haemoglobins Rainier and Bethesda hinge on the substitution of a vital tyrosine residue, which stabilizes the deoxy form of normal haemoglobin. Replacement of this tyrosine therefore results in high oxygen affinity and low co-operativity.     

Phylogeny and biogeography of Carminator (Hymenoptera: Megalyridae)

Carminator Shaw is a small genus of parasitic wasps that is mainly distributed in Southeast Asia. Eight species are recognized here, including Carminator coronatus sp.n. and Carminator gracilis sp.n. A data set comprising 54 morphological characters and including all the known species of Carminator, as well as four out‐group taxa (two Cryptalyra spp., one Ettchellsia sp. and one Megalyra sp.), was assembled and analysed. Carminator is retrieved as monophyletic. All weighted analyses place Carminator affinis as the sister group to the rest of the genus. A northern clade comprising species occurring on the Japanese Isles, Taiwan and Vietnam (Carminator japonicus (Carminator gracilis sp.n. (Carminator cavus + Carminator helios))) is strongly supported and nested inside the more southerly distributed species. C. helios is found on Nakanoshima Island, which emerged post‐Pliocene, and so C. helios is considered to have dispersed there via a land‐bridge connection from the Ryukyu Islands. A key to all known species of Carminator is provided.     

Acid-base induced calcium uptake by spinach chloroplasts

Calcium uptake by spinach chloroplasts can be induced by thetransition from an acidic to a basic medium. This reaction dependsupon the pH difference. A difference by 4.3 to 4.5 pH unitsshowed a maximum efficiency for calcium uptake. The acid-baseinduced calcium uptake is susceptible to various inhibitorsin a way similar to that of light-induced calcium uptake. Thesame high energy intermediate (or state) produced in the chloroplastby this acid-base transition is inferred to be operating bothin calcium uptake and ATP formation. (Received March 12, 1969; )