Optimal and synchronized germination of Robinia pseudoacacia,Acacia dealbata and other woody Fabaceae using a handheld rotary tool:concomitant reduction of physical and physiological seed dormancy

The Fabaceae(legume family) is one of the largest families of plants with a worldwide distribution and a major role in agriculture and in agroforestry.A hard seed coat impermeable to water is a typical feature of several species.Physical dormancy delays and reduces germination so that mechanical,physical and chemical scarification methods have been classically used to break seed dormancy of many species.We evaluate the effectiveness of a methodology to scarify seeds of several woody Fabaceae of ecological and economical importance,including Robinia pseudoacacia and Acacia dealbata and the shrubs Cytisus scoparius,C.multiflorus and Ulex europaeus.We describe the optimized use of a handheld rotary tool(HRT),and compare its effectiveness with other scarification methods reported to break dormancy such as boiling or dry heating.Total germination and/or speed of germination were enhanced after the application of the HRT,with germination percentages significantly higher than those achieved by other methods of scarification.Based on a thorough literature review,a mode of action for the HRT is suggested which could operate by breaking the physical and physiological dormancy of treated seeds through thecombined action of coat abrasion and moderate temperatures.Considering these results,we recommend the application of this rapid,effective,low-cost and highly reproducible HRT method to break seed dormancy and enhance germination of these species and others with similar dormancy constraints.

Weathering Processes on Martian Craters: Implications on Recurring Slope Lineae and the Location of Liquid Water

Recent attention has been put into recurring slope lineae (RSL), after the discovery that water is present in them. It is assumed that RSL are due to flowing water. However, even though that might be the case, the general characteristics of RSL as well as their seasonal and spatial distribution in Mars, and their occurrence within craters, suggest that RSL correspond to the weathering of frozen aquifers, which coincides with slope stability processes occurring in impact craters and scree slopes from Earth. In this study, we associated RSL with similar weathering processes occurring on impact craters and hydrogeological processes occurring on Earth (including ice, water, and wind erosion and natural aquifer recharge processes). We were able to create a conceptual model on how RSL develop, why are they found mostly in mid latitudes around craters, why are they present in more frequency in one side of crates in high latitudes, and why are there more RSL in the Martian southern hemisphere. Considering the whole hydrogeological processes occurring in craters that experience RSL, we were able to predict where large quantities of liquid water are most likely to be present in the red planet.

Clones identification of Sequoia sempervirens (D. Don) Endl. in Chile by using PCR-RAPDs technique

A protocol of polymerase chain reaction-random amplified polymorphic DNAs (PCR-RAPDs) was established to analyse the gene diversity and genotype identification for clones of Sequoia sempervirens (D. Don) Endl. in Chile. Ten (out of 34) clones from introduction trial located in Voipir-Villarrica, Chile, were studied. The PCR-RAPDs technique and a modified hexadecyltrimethylammonium bromide (CTAB) protocol were used for genomic DNA extraction. The PCR tests were carried out employing 10-mer random primers. The amplification products were detected by electrophoresis in agarose gels. Forty nine polymorphic bands were obtained with the selected primers (BG04, BF07, BF12, BF13, and BF14) and were ordered according to their molecular size. The genetic similarity between samples was calculated by the Jaccard index and a dendrogram was con- structed using a cluster analysis of unweighted pair group method using arithmetic averages (UPGMA). Of the primers tested, 5 (out of 60) RAPD primers were selected for their reproducibility and high polymorphism. A total of 49 polymorphic RAPD bands were detected out of 252 bands. The genetic similarity analysis demonstrates an extensive genetic variability between the tested clones and the dendrogram depicts the genetic relationships among the clones, suggesting a geographic relationship. The results indicate that the RAPD markers permitted the identification of the assayed clones, although they are derived from the same geo- graphic origin.

Congratulations on the 99th anniversary of the founding of the Communist Party of China

The Communist Party of China is the most important political party in the world today,having led the Chinese people to achieve the greatest economic and social transformation in the shortest time in the history of humanity.The Party has 92 million members,of which 28 percent are women and 7.4 percent are from minority ethnic groups.