Genetic diversity increases regional variation in phenological dates in response to climate change

Climate change is inducing changes in the phenological timings of organisms. Genetic diversity could influence phenological responses to climate change, but empirical evidence is very limited. We estimated the regional variation across Japan in flowering and leaf budburst dates of plants based on a dataset of phenological timings from 1953 to 2005. The observed plants' genetic diversities varied according to human cultivation. The within-species variations of phenological response to temperature as well as regional variations were less in the plant populations with lower genetic diversity. Thus, genetic diversity influences the variation in phenological responses of plant populations. Under increased temperatures, low variation in phenological responses may allow drastic changes in the phenology of plant populations with synchronized phenological timings. Our findings indicate that we should pay attention to maintaining genetic diversity of populations to alleviate changes in phenology due to future climate change.     

INSTABILITY OF MESSENGER AND RIBOSOMAL RNA IN A GLUE-PROTEIN MUTANT OF Bombyx mori

The mucous glands of Bombyx pupae secrete glue proteins which attach deposited eggs to the mounting sheet. A mutant of a dominant gene, named no glue (Ng) , produces nonadhesive eggs which have a low capacity for glue-protein synthesis. In the present study it was shown that the mucous glands of Ng silkworms showed rapid degradation of mRNA as well as rRNA during development; this may cause the low capacity for glue-protein synthesis in the mutant organ. In contrast, the mucous glands of normal silkworms showed a significant increase in content of RNA's until the maximum rate of glue-protein synthesis was achieved. The degradation of RNA in the Ng mucous gland was inhibited by actinomycin D injected into the body fluid. Thus it is supposed that the Ng gene codes for a presumptive controller RNA, which would be the mediator of RNA instability in the mucous glands of Ng pupae.     

Effects of light, temperature and water stress on germination of Artemisia sphaerocephala

Artemisia sphaerocephala is widely used for vegetation rehabilitation, but its germination is very low after air seeding of achenes. We explored effects of light, temperature and water stress on germination. Results show that both final percent germination and germination rate were increased by temperature increment, with the highest values occurring at 15: 25°C (night: day) in dark and 20: 30°C under light. Light inhibited germination, especially at lower alternating temperatures (5: 15°C and 10: 20°C). The alternating temperature window for germination was slightly narrower under light than in dark, and germination was slower under light than in dark across the temperature range. Achenes incubated in the dark and at constant temperatures had over 80% germination at 10 to 25°C, with an optimum at 20°C. Under dark and 25μmol m^‐2 s^‐1 light flux density at 10: 20°C, final percent germination was over 94%, but if the light flux density was increased to 100 and 400 μmol m^‐2 s^‐1, final percent germination was significantly lower (64% and 38% respectively). However, achenes could keep their germination capacity for a long time (over 50 days) and germinate well after going back to the dark. Germination was also lower under water stress and few achenes germinated at ‐1.4 MPa. This was more pronounced at high and low temperatures. Given these findings and the prevailing climatic characteristics, the most suitable time for air seeding of achenes may be mid‐May.     

Enzymic synthesis of floridean starch in a red alga, Serraticardia maxima

ADP-glucose: -l,4-glucan -4-glucosyltransferase was obtainedfrom a marine red alga Serraticardia maxima in a form boundwith floridean starch granules. The enzyme catalyzed the transferof glucosyl residue from ADP-glucose, UDP-glucose and GDP-glucoseto floridean starch added as a primer. ADP-glucose was the mostefficient glucosyl donor in the reaction. Maltose was producedby ß-amylolysis of the glucan synthesized by the algalenzyme. The optimum pH for enzyme activity was at 8.4. The enzymewas not obtained in a soluble form from either the chloroplastextract or the whole algal cell extract. Electron micrographsof algal cells revealed that floridean starch granules are localizedexclusively outside chloroplasts. Hence, it appears that mostof the synthetase is present outside chloroplasts. ¹ Contribution from the Shimoda Marine Biological Station, TokyoKyoiku University, No. 202. This work was supported by a Grant-in-Aidfor Cooperative Research from the Ministry of Education, Japan. ² Present address: Department of Biology, Faculty of Science,Science University of Tokyo, Kagurazaka, Tokyo 162, Japan. ³ Present address: Laboratory of Biology, Faculty of Science,Toho University, Narashino, Chiba 275, Japan. (Received May 25, 1970; )     

Genome-wide Analysis of Transcript Abundance and Translation in Arabidopsis Seedlings Subjected to Oxygen Deprivation

Annals of Botany 96: 647–660, 2005 Unfortunately, there were errors in Figure 5 of this article.The     

Sprouting traits and population structure of co-occurring Castanopsis species in an evergreen broad-leaved forest in southern China

The role of sprouting in regeneration was compared betweenfour co-occurring Castanopsis species in an evergreen broad-leavedforest in southern China. We considered the largest stem of an individualto be the main stem, while all of the other stems were consideredto be sprouts. To evaluate the degree of dependence on sproutingin the regeneration of each species, we measured the ratio of thenumber of all sprouts to the number of main stems in a population. The ratio was 4.3 in Castanopsis fordii and > 1in Castanopsis fabri and Castanopsis carlesii, althoughit was < 1 in Castanopsis fargesii. The ratioof the number of all sprouts to the number of main stems in a populationwas represented by the product of two factors of sprouting ability:the proportion of sprouting individuals among all individuals andthe number of sprouts per sprouting individual. The proportion ofsprouting individuals among all individuals differed significantlyamong the four species, while the number of sprouts per sproutingindividual did not. Specific variations in sprouting traits werein agreement with the population structure of each species. Specieswith fewer small individuals in the size distribution had a higherratio than species with L-shaped distribution. Furthermore, specieswith a clumped distribution had a larger ratio than species thatwere randomly distributed. These results suggested that specieswhose recruitment by seedlings was temporally and spatially restrictedwere relatively more dependent on sprouting in the regeneration. The specific gradient of sprouting ability and the relative dependencyon sprouts to maintain a population can enhance the coexistenceof these four congeneric species.