History of Modern Plant Science
Early plant science
The history of botany begins with ancient writings on, and classifications of, plants. Such writings are found in several early cultures. Examples of early botanical works have been found in Ancient Indian sacred texts, ancient Zoroastrian writings and ancient Chinese works. Theophrastus (371–287 B.C.E.) has been frequently referred to as the ‘father of botany’. The Greco-Roman world produced a number of botanical works including Theophrastus's Historia Plantarum and Dioscorides' De Materia Medica from the first century.
Works from the medieval Muslim world included Ibn Wahshiyya's Nabatean Agriculture, Abū Ḥanīfa Dīnawarī's (828-896) the Book of Plants, and Ibn Bassal's The Classification of Soils. In the early 13th century, Abu al-Abbas al-Nabati, and Ibn al-Baitar (1248 C.E.) also wrote on botany.
German physician Leonhart Fuchs (1501–1566) was one of the three founding fathers of botany, along with Otto Brunfels (1489–1534) and Hieronymus Bock (1498–1554). Valerius Cordus (1515–1544) authored a pharmacopoeia of lasting importance, the Dispensatorium in 1546. Conrad von Gesner (1516–1565) and Nicholas Culpeper (1616–1654) also published herbals covering the medicinal uses of plants. Ulisse Aldrovandi (1522–1605) was considered the ‘father of natural history’, which included the study of plants. In 1665, using an early microscope, Robert Hooke discovered cells, a term he coined, in cork, and a short time later in living plant tissue.
During the 18th century, systems of classification became deliberately artificial and served only for the purpose of identification. These classifications are comparable to diagnostic keys, where taxa are artificially grouped in pairs by few, easily recognisable characters. The sequence of the taxa in keys is often totally unrelated to their natural or phyletic groupings. In the 18th century an increasing number of new plants had arrived in Europe, from newly discovered countries and the European colonies worldwide, and a larger amount of plants became available for study.
In 1754 Carl von Linné (Carl Linnaeus) divided the plant Kingdom into 25 classes. One, the Cryptogamia, included all plants with concealed reproductive parts (mosses, liverworts and ferns), and algae and fungi.
The increased knowledge of anatomy, morphology and life cycles, lead to the realisation that there were more natural affinities between plants, than the sexual system of Linnaeus indicated. Adanson (1763), de Jussieu (1789), and Candolle (1819) all proposed various alternative natural systems that were widely followed. The ideas of natural selection as a mechanism for evolution required adaptations to the Candollean system, which started the studies on evolutionary relationships and phylogenetic classifications of plants.
Botany was greatly stimulated by the appearance of the first modern text book, Matthias Schleiden's Grundzuge der Wissenschaftlichen, published in English in 1849 as Principles of Scientific Botany. Carl Willdenow examined the connection between seed dispersal and distribution, the nature of plant associations, and the impact of geological history. The cell nucleus was discovered by Robert Brown in 1831.
Modern plant science
A considerable amount of new knowledge today is being generated from studying model plants like Arabidopsis thaliana. This weedy species in the mustard family was one of the first plants to have its genome sequenced. The sequencing of the rice (Oryza sativa) genome, its relatively small genome, and a large international research community have made rice an important cereal, grass and monocot model. Another grass species, Brachypodium distachyon is also an experimental model for understanding genetic, cellular and molecular biology. Other commercially important staple foods like wheat, maize, barley, rye, pearl millet and soybean are also having their genomes sequenced. Some of these are challenging to sequence because they have more than two haploid (n) sets of chromosomes, a condition known as polyploidy, common in the plant kingdom. A green alga, Chlamydomonas reinhardtii, is model organism that has proven important in advancing knowledge of cell biology.
In 1998 the Angiosperm Phylogeny Group published a phylogeny of flowering plants based on an analysis of DNA sequences from most families of flowering plants. As a result of this work, major questions such as which families represent the earliest branches in the genealogy of angiosperms are now understood. Investigating how plant species are related to each other allows botanists to better understand the process of evolution in plants. Despite the study of model plants and DNA, there is continual on-going work and discussion among taxonomists about how best to classify plants into various taxa.