Hydrophily is a fairly uncommon form of pollination whereby pollen is distributed by the flow of waters, particularly in rivers and streams. Hydrophilous species fall into two categories: (i) Those that distribute their pollen to the surface of water. e.g. Vallisneria's male flower or pollen grain are released on the surface of water, which are passively carried away by water currents; some of them eventually reach the female flower (ii) Those that distribute it beneath the surface. e.g. seagrasses in which female flower remain submergered in water and pollen grains are released inside the water.
Surface pollination is more frequent, [1] and appears to be a transitional phase between wind pollination and true hydrophily. In these the pollen floats on the surface and reaches the stigmas of the female flowers as in Hydrilla , Callitriche , Ruppia , Zostera , Elodea . In Vallisneria the male flowers become detached and float on the surface of the water; the anthers are thus brought in contact with the stigmas of the female flowers. [1] Surface hydrophily has been observed in several species of Potamogeton as well as some marine species. [2]
Species exhibiting true submerged hydrophily include Najas , where the pollen grains are heavier than water, and sinking down are caught by the stigmas of the extremely simple female flowers, [1] Posidonia australis or Zostera marina [3] and Hydrilla.
Hydrophily is unique to obligate submersed aquatic angiosperms with sexually reproductive parts completely submerged below the water surface. Hydrophily is the adaptive evolution of completely submersed angiosperms to aquatic habitats. True hydrophily occurs in 18 submersed angiosperm genera, which is associated with an unusually high incidence of unisexual flowers. [4]
The Alismatales (alismatids) are an order of flowering plants including about 4,500 species. Plants assigned to this order are mostly tropical or aquatic. Some grow in fresh water, some in marine habitats. Perhaps the most important food crop in the order is the corm of the taro plant, Colocasia esculenta.
Pollen is a powdery substance produced by flowers of seed plants. It consists of pollen grains, which produce male gametes. Pollen grains have a hard coat made of sporopollenin that protects the gametophytes during the process of their movement from the stamens to the pistil of flowering plants, or from the male cone to the female cone of gymnosperms. If pollen lands on a compatible pistil or female cone, it germinates, producing a pollen tube that transfers the sperm to the ovule containing the female gametophyte. Individual pollen grains are small enough to require magnification to see detail. The study of pollen is called palynology and is highly useful in paleoecology, paleontology, archaeology, and forensics. Pollen in plants is used for transferring haploid male genetic material from the anther of a single flower to the stigma of another in cross-pollination. In a case of self-pollination, this process takes place from the anther of a flower to the stigma of the same flower.
Aquatic plants are plants that have adapted to living in aquatic environments. They are also referred to as hydrophytes or macrophytes to distinguish them from algae and other microphytes. A macrophyte is a plant that grows in or near water and is either emergent, submergent, or floating. In lakes and rivers macrophytes provide cover for fish, substrate for aquatic invertebrates, produce oxygen, and act as food for some fish and wildlife.
Pollination is the transfer of pollen from an anther of a plant to the stigma of a plant, later enabling fertilisation and the production of seeds, most often by an animal or by wind. Pollinating agents can be animals such as insects, birds, and bats; water; wind; and even plants themselves, when self-pollination occurs within a closed flower. Pollination often occurs within a species. When pollination occurs between species, it can produce hybrid offspring in nature and in plant breeding work.
Hydrocharitaceae is a flowering plant family including 16 known genera with a total of ca 135 known species, that including a number of species of aquatic plant, for instance the tape-grasses, the well known Canadian waterweed, and frogbit.
Vallisneria is a genus of freshwater aquatic plant, commonly called eelgrass, tape grass or vallis. The genus is widely distributed in tropical and subtropical regions of Asia, Africa, Europe, and North America.
Anemophily or wind pollination is a form of pollination whereby pollen is distributed by wind. Almost all gymnosperms are anemophilous, as are many plants in the order Poales, including grasses, sedges, and rushes. Other common anemophilous plants are oaks, pecans, pistachios, sweet chestnuts, alders and members of the family Juglandaceae. Approximately 12% of plants across the globe are pollinated by anemophily, including cereal crops like rice and corn and other prominent crop plants like wheat, rye, barley, and oats. In addition, many pines, spruces, and firs are wind-pollinated.
Entomophily or insect pollination is a form of pollination whereby pollen of plants, especially but not only of flowering plants, is distributed by insects. Flowers pollinated by insects typically advertise themselves with bright colours, sometimes with conspicuous patterns leading to rewards of pollen and nectar; they may also have an attractive scent which in some cases mimics insect pheromones. Insect pollinators such as bees have adaptations for their role, such as lapping or sucking mouthparts to take in nectar, and in some species also pollen baskets on their hind legs. This required the coevolution of insects and flowering plants in the development of pollination behaviour by the insects and pollination mechanisms by the flowers, benefiting both groups. Both the size and the density of a population are known to affect pollination and subsequent reproductive performance.
The stigma is the receptive tip of a carpel, or of several fused carpels, in the gynoecium of a flower.
Velloziaceae is a family of monocotyledonous flowering plants. The APG II system, of 2003, also recognizes this family, and assigns it to the order Pandanales.
A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants. Flowers produce gametophytes, which in flowering plants consist of a few haploid cells which produce gametes. The "male" gametophyte, which produces non-motile sperm, is enclosed within pollen grains; the "female" gametophyte is contained within the ovule. When pollen from the anther of a flower is deposited on the stigma, this is called pollination. Some flowers may self-pollinate, producing seed using pollen from the same flower or a different flower of the same plant, but others have mechanisms to prevent self-pollination and rely on cross-pollination, when pollen is transferred from the anther of one flower to the stigma of another flower on a different individual of the same species.
Cymodoceaceae is a family of flowering plants, sometimes known as the "manatee-grass family", which includes only marine species.
Pollination syndromes are suites of flower traits that have evolved in response to natural selection imposed by different pollen vectors, which can be abiotic or biotic, such as birds, bees, flies, and so forth through a process called pollinator-mediated selection. These traits include flower shape, size, colour, odour, reward type and amount, nectar composition, timing of flowering, etc. For example, tubular red flowers with copious nectar often attract birds; foul smelling flowers attract carrion flies or beetles, etc.
Plant reproduction is the production of new offspring in plants, which can be accomplished by sexual or asexual reproduction. Sexual reproduction produces offspring by the fusion of gametes, resulting in offspring genetically different from either parent. Asexual reproduction produces new individuals without the fusion of gametes, resulting in clonal plants that are genetically identical to the parent plant and each other, unless mutations occur.
This page provides a glossary of plant morphology. Botanists and other biologists who study plant morphology use a number of different terms to classify and identify plant organs and parts that can be observed using no more than a handheld magnifying lens. This page provides help in understanding the numerous other pages describing plants by their various taxa. The accompanying page—Plant morphology—provides an overview of the science of the external form of plants. There is also an alphabetical list: Glossary of botanical terms. In contrast, this page deals with botanical terms in a systematic manner, with some illustrations, and organized by plant anatomy and function in plant physiology.
Potamogeton diversifolius is a species of aquatic plant known by the common names waterthread pondweed and diverse-leaved pondweed. It is native to most of the United States, as well as sections of southwestern Canada, and northern Mexico, where it grows in water bodies such as ponds, lakes, ditches, and slow-moving streams. This is a perennial herb producing a very narrow, compressed stem branching to a maximum length around 35 centimeters. It has thin, pointed linear leaves a few centimeters long spirally arranged about the thin stem. The inflorescence is a small spike of flowers emerging from the water surface. Inflorescences also grow on submersed sections of the stem; these are smaller and spherical. It can be difficult to distinguish from similar species of pondweed.
Thalassia testudinum, commonly known as turtlegrass, is a species of marine seagrass. It forms meadows in shallow sandy or muddy locations in the Caribbean Sea and the Gulf of Mexico. Turtle grass and other seagrasses form meadows which are important habitats and feeding grounds. The grass is eaten by turtles and herbivorous fish, supports many epiphytes, and provides habitat for juvenile fish and many invertebrate taxa.
The monocots are one of the two major groups of flowering plants, the other being the dicots. In order to reproduce they utilize various strategies such as employing forms of asexual reproduction, restricting which individuals they are sexually compatible with, or influencing how they are pollinated. Nearly all reproductive strategies that evolved in the dicots have independently evolved in monocots as well. Despite these similarities and their close relatedness, monocots and dicots have distinct traits in their reproductive biologies.
The pollination of orchids is a complex chapter in the biology of this family of plants that are distinguished by the complexity of their flowers and by intricate ecological interactions with their pollinator agents. It has captured the attention of numerous scientists over time, including Charles Darwin, father of the theory of evolution by natural selection. Darwin published in 1862 the first observations of the fundamental role of insects in orchid pollination, in his book The Fertilization of Orchids. Darwin stated that the varied stratagems orchids use to attract their pollinators transcend the imagination of any human being.