Archive for the ‘Botany’ Category
The results of a new study could change the concept that scientists have about how some plants are oriented toward the light.
The process, called phototropism, is well documented in some vegetables, but has proved difficult to understand well in dicotyledonous plants, a large group of flowering plants which include many agricultural crops.
Charles Darwin and his son Francis described the phototropism at the end of the 19th century, based on experiments in which prevented the light to reach the tips of the shoots of the plants and avoided so these vegetables are oriented towards the light. Their work led to the discovery of auxin, a plant hormone that controls the functions of growth. Read the rest of this entry »
The plants are adapted to local conditions of climate and soil where they grow, and it is known that these adaptations to the environment for thousands of years evolve as mutations that accumulate little by little in their genetic code. Now it has been discovered that at least in some plants these adaptations can arise almost instantly, not by a change in DNA sequence, but simply by duplication of existing genetic material.
While almost all animals have two sets of chromosomes, one of maternal origin and one of paternal origin, many plants are polyploid, which means they have four or more sets of chromosomes. The exact role that the polyploid condition has on the ability of a wild plant to survive environmental changes noticeable to colonize new habitats or had not been examined by experiments as stringent as those now made in a new study. Read the rest of this entry »
It was thought that land plants that started to colonize land about 500 million years had evolved from algae closely related to the genus Chara. However, new research shows that the closest evolutionary relatives of land plants are those algae, but other vegetables.
The main reason is believed that algae were the order Charales closest evolutionary relatives of land plants is that they share, among other common characteristics, a similar method of fertilization.
However, research carried out by a team of specialists from the Botanical Institute of the University of Cologne, Fritz Lipmann Institute in Jena, Germany, and the University of Montreal in Canada, has brought new light to indicate other evolutionary origin. Read the rest of this entry »