The categories of plant products which directly affect human life

The categories of plant products which directly affect human life: submitted for the Anderson-Henry Prize in Botany, 1936It has been impossible in the short space of an essay to mention all the plant products which directly affect human life, but, without any claim to completeness, it may be said that almost every species of really first -rate importance has been mentioned. When it is remembered that there are something like 250,000 known species of flowering plants, it is realised that man utilises intensively a mere handful of the available flora.It would seem that man, early in his history, exploited the cream of the world's useful plants, and that they have sufficed him ever since. Civilisation has tended to spread already utilised species rather than develop new ones. This is not to say that no others can be used, but that, as is natural enough, the line of least resistance has been pursued. While the products of one species suffice there is little inducement to develop others, but if the source of raw material is cut off, additional species formerly ignored are soon pressed into use. This was strikingly illustrated during the Great War. The plants which can be thus utilised when need arises constitute, as it were, a reserve for future exploitation.While little has been done as yet by modern science in the direction of developing entirely new cultivated species from natural wild plants, much has been done in the way of improving existing varieties of valuable cultivated plants, and in increasing crop yield by manuring and rotation.Until about half a century ago, the only methods known of improving plant breeds were selection and hybridisation, but a far more valuable method is now available, thanks to the researches of Mendel. It is impossible to discuss the vast subject of Mendelism here, but expressed shortly its value lies in that, by following certain well defined laws, it is possible to vary the constitution of a race very much, and to eliminate many undesirable characters.In the control and prevention of plant diseases scientific investigation again has been of the greatest possible value. Some diseases have been eradicated almost completely, and others brought under some degree of control.The trend of modern agriculture then appears to be in the direction of the improvement of existing species of cultivated plants, and in increasing the yield per acre of cultivated land.Finally might I emphasise just once again the dependence of man on the plant world. The most fundamental fact about the human race is that, biologically, man is an animal, and is in the most fundamental respects little different from the other members of that class. It is true that man has, by the development of reason, risen to a position of dominance over other living things, but the high level of culture which he has attained has increased rather than lowered his dependence on plant products. He is indeed a parasite on the green leaf

Ground beetle assemblages in Beijing’s new mountain forests

Mature forests have been almost completely destroyed in China’s northern regions, but this has been followed by large-scale reforestation in the wake of environmental degradation. Although future forest plantations are expected to expand over millions of hectares, knowledge about the ecology and biodiversity of China’s replanted forests remains very limited. Addressing these knowledge gaps, we recorded ground beetle (Coleoptera: Carabidae) communities in five secondary forest types: plantations of Chinese Pine (Pinus tabulaeformis) and Prince Rupprecht’s Larch (Larix principis-rupprechtii), Oak (Quercus wutaishanica) and Asian White Birch (Betula platyphylla) woodlands, and naturally regenerated mixed forest. Species richness peaked in mixed forests, while pine and oak woodlands harboured discrete communities of intermediate species richness. Oak, pine and mixed forest habitats also showed high levels of species turnover between plots. Canopy closure was an important factor influencing ground beetle assemblages and diversity, and a number of forest specialist species only occurred in pine or oak forests. We believe that some forest specialists have survived earlier deforestation and appear to be supported by new plantation forests, but maintenance of secondary native oak and mixed forests is crucial to safeguard the overall species pool

Laboratory techniques in biochemistry and molecular biology /

Includes bibliographies.1. Electrophoresis of proteins in polyacrylamide and starch cells / A. H. Gordon2. An introduction to gel chromatography / L. Fischer3. Immunochemical techniques for the identification and estimation of macromolecules / J. Clause