What is the difference between pollination and fertilization in gymnosperms

The working of this self-incompatibility mechanism has important consequences for plant breeders because it inhibits the production of inbred and hybrid plants. Figure 1. Insects, such as bees, are important agents of pollination. Bees are perhaps the most important pollinator of many garden plants and most commercial fruit trees Figure 1. The most common species of bees are bumblebees and honeybees. Since bees cannot see the color red, bee-pollinated flowers usually have shades of blue, yellow, or other colors.

Bees collect energy-rich pollen or nectar for their survival and energy needs. They visit flowers that are open during the day, are brightly colored, have a strong aroma or scent, and have a tubular shape, typically with the presence of a nectar guide.

A nectar guide includes regions on the flower petals that are visible only to bees, and not to humans; it helps to guide bees to the center of the flower, thus making the pollination process more efficient. Recently, there have been many reports about the declining population of honeybees. Many flowers will remain unpollinated and not bear seed if honeybees disappear.

The impact on commercial fruit growers could be devastating. Many flies are attracted to flowers that have a decaying smell or an odor of rotting flesh. These flowers, which produce nectar, usually have dull colors, such as brown or purple. They are found on the corpse flower or voodoo lily Amorphophallus , dragon arum Dracunculus , and carrion flower Stapleia , Rafflesia.

The nectar provides energy, whereas the pollen provides protein. Wasps are also important insect pollinators, and pollinate many species of figs. Figure 2. A corn earworm sips nectar from a night-blooming Gaura plant. Butterflies, such as the monarch, pollinate many garden flowers and wildflowers, which usually occur in clusters.

These flowers are brightly colored, have a strong fragrance, are open during the day, and have nectar guides to make access to nectar easier. Moths, on the other hand, pollinate flowers during the late afternoon and night. The flowers pollinated by moths are pale or white and are flat, enabling the moths to land. One well-studied example of a moth-pollinated plant is the yucca plant, which is pollinated by the yucca moth. The shape of the flower and moth have adapted in such a way as to allow successful pollination.

The moth deposits pollen on the sticky stigma for fertilization to occur later. The female moth also deposits eggs into the ovary. As the eggs develop into larvae, they obtain food from the flower and developing seeds. Thus, both the insect and flower benefit from each other in this symbiotic relationship. The corn earworm moth and Gaura plant have a similar relationship Figure 2. In the tropics and deserts, bats are often the pollinators of nocturnal flowers such as agave, guava, and morning glory.

The flowers are usually large and white or pale-colored; thus, they can be distinguished from the dark surroundings at night. The flowers have a strong, fruity, or musky fragrance and produce large amounts of nectar. They are naturally large and wide-mouthed to accommodate the head of the bat. As the bats seek the nectar, their faces and heads become covered with pollen, which is then transferred to the next flower.

Figure 3. Hummingbirds have adaptations that allow them to reach the nectar of certain tubular flowers. Many species of small birds, such as the hummingbird Figure 3 and sun birds, are pollinators for plants such as orchids and other wildflowers.

Flowers visited by birds are usually sturdy and are oriented in such a way as to allow the birds to stay near the flower without getting their wings entangled in the nearby flowers. Brightly colored, odorless flowers that are open during the day are pollinated by birds. Botanists have been known to determine the range of extinct plants by collecting and identifying pollen from year-old bird specimens from the same site.

Most species of conifers, and many angiosperms, such as grasses, maples and oaks, are pollinated by wind. Pine cones are brown and unscented, while the flowers of wind-pollinated angiosperm species are usually green, small, may have small or no petals, and produce large amounts of pollen.

Unlike the typical insect-pollinated flowers, flowers adapted to pollination by wind do not produce nectar or scent. In wind-pollinated species, the microsporangia hang out of the flower, and, as the wind blows, the lightweight pollen is carried with it Figure 4.

The flowers usually emerge early in the spring, before the leaves, so that the leaves do not block the movement of the wind. The pollen is deposited on the exposed feathery stigma of the flower Figure 5. Figure 5. These male a and female b catkins are from the goat willow tree Salix caprea. Note how both structures are light and feathery to better disperse and catch the wind-blown pollen.

Some weeds, such as Australian sea grass and pond weeds, are pollinated by water. The pollen floats on water, and when it comes into contact with the flower, it is deposited inside the flower.

Figure 6. Certain orchids use food deception or sexual deception to attract pollinators. Shown here is a bee orchid Ophrys apifera. Orchids are highly valued flowers, with many rare varieties Figure 6.

They grow in a range of specific habitats, mainly in the tropics of Asia, South America, and Central America. At least 25, species of orchids have been identified.

Flowers often attract pollinators with food rewards, in the form of nectar. However, some species of orchid are an exception to this standard: they have evolved different ways to attract the desired pollinators. They use a method known as food deception, in which bright colors and perfumes are offered, but no food.

Anacamptis morio , commonly known as the green-winged orchid, bears bright purple flowers and emits a strong scent. The bumblebee, its main pollinator, is attracted to the flower because of the strong scent—which usually indicates food for a bee—and in the process, picks up the pollen to be transported to another flower. Other orchids use sexual deception. Chiloglottis trapeziformis emits a compound that smells the same as the pheromone emitted by a female wasp to attract male wasps.

But only flowering plants undergo the process of pollination, while fertilization is the common process of almost all living being. Continuation of life would not have been possible without the presence of plants, as directly or indirectly every organism depends on them.

Like the various other organisms which reproduce sexually, the same way flowering plants also do. To forward their characters to other generation and to increase their population size, the plants mainly reproduces in two ways- Pollination and Fertilization. In this process, flowering plants reproduce by combining egg cells and sperm cells , to form a zygote.

This zygote matures into the seeds and grows the next generation. Female egg cells are present in the ovary while male sperm is present in the pollen grains. In this article, we will be going through the important points which distinguish these two processes along with some more additional information on them.

Basis for Comparison Pollination Fertilization Meaning The process of transfer of pollen from the male parts anther of a flower to the female part stigma of the same or different flower is called as pollination. Whereas the fertilization is the common process, involving the union of the male gamete sperm and female gamete egg.

Pollen tube No formation of the pollen tube. Formation of pollen tube which helps in transferring of male gametes up to an egg cell. Kind of mechanism It is an external mechanism and takes place on the outer part of a flower. It is an internal mechanism and takes place inside the flowers. Time of process Pollination takes place before fertilization.

Fertilization takes place after pollination. Type Two types: Self-pollination. No types. It occurs in Pollination occurs in flowering plants only. Li, G. Ontogeny of pollen and pollination in Keteleeria fortunei. Silvae Sinicae 42, 42— Little, S. Ramatt, J. Lora, J. The diversity of the pollen tube pathway in plants: toward an increasing control by the sporophyte. Lu, Y. Phylogeny and divergence times of gymnosperms inferred from single-copy nuclear gene.

PLoS One 9:e The morphology, ultrastructure, element distribution and motion behaviour in pollen of Ginkgo biloba L. Trees 30, — Marazzi, B. The diversity, ecology and evolution of extrafloral nectaries: current perspectives and future challenges. Matten, L.

The megagametophyte of Hydrasperma tenuis from the Upper Devonian of Ireland. McWilliam, J. Interspecific incompatibility in Pinus. Meeuse, A. Entomophily in the dioecious gymnosperm Ephedra aphylla Forsk. Further anthecological studies and relative importance of entomophily. Mehra, P. The germination of pollen grains in artificial cultures in Ephedra foliata Boiss and Ephedra gerardiana Wall. Indian Acad. B 8, — Meyen, S.

Basic features of gymnosperm systematics and phylogeny as evidenced in the fossil record. Mill, R. Morphology, anatomy and ontogeny of female cones in Acmopyle pancheri Brogn. Comparative biology of the pollination mechanisms in Acmopyle pancheri and Phyllocladus hypophyllus Podocarpaceae s. Molloy, P. Manoao Podocarpaceae , a new monotypic conifer genus endemic to New Zealand. Mound, L. Thrips pollination of the central Australian cycad, Macrozamia macdonnellii Cycadales. Moussel, B.

Mugnaini, S. Pollination drop in Juniperus communis : response to deposited material. Pollination drop withdrawal in Juniperus communis : response to biotic and abiotic particles. Caryologia 60, — Nepi, M. New perspectives in nectar evolution and ecology: simple alimentary reward or a complex multiorganism interaction?

Acta Agron. Nectar secretion, reabsorption, and sugar composition in male and female flowers of Cucurbita pepo. Phylogenetic and functional signals in gymnosperm ovular secretions. Nectar and pollination drops: how different are they? Niklas, K. The influence of Paleozoic ovule and cupule morphologies on wind pollination. Evolution 37, — Aerodynamics of wind pollination.

Nishida, H. Zooidogamy in the late Permian genus Glossopteris. Plant Res. New evidence of reproductive organs of Glossopteris based on permineralized fossils from Queensland, Australia. Ovulate organ Homevaleia gen. Swimming sperm in an extinct Gondwanan plant. Nature , — Zur Kenntnis der Entwicklung von Saxegothaea conspicua Lindl.

Svensk Botanisk Tidskrift 2, — Norstog, K. The Biology of Cycads. Ithaca: Cornell University Press. The role of beetles in the pollination of Zamia furfuracea L Fil Zamiaceae. Biotropica 18, — Nygaard, P. Utilization of exogenous carbohydrates for tube growth and starch synthesis in pine pollen suspension cultures.

Origin of arabinogalactan proteins in the pollination drop of Taxus x media. Austrian J. Identification of two thaumatin-like proteins TLPs in the pollination drop of hybrid yew that may play a role in pathogen defence during pollen collection.

Tree Physiol. Postpollination drop production in hybrid larch is not related to the diurnal pattern of xylem water potential.

Trees 20, 61— Oliver, F. On Phystoma elegans , Williamson, an archaic type of seed from the Paleozoic rocks. Ortiz-Ramirez, C. Glutamate receptor-like channels are essential for chemotaxis and reproduction in mosses. Nature , 91— Owens, J. The pollination mechanism of Sitka spruce Picea sitchensis. The pollination mechanism of western white pine. The reproductive biology of Kauri Agathis australis. Pollination and prefertilization development.

Sexual reproduction of Abies amabilis. The pollination mechanism of Engelmann spruce Picea engelmannii. The pollination mechanism in yellow cypress Chamaecyparis nootkatensis. Pollination in conifers. Paulson, A. Transcriptome analysis provides insight into venom evolution in a seed-parasitic wasp. Megastigmus spermotrophus. Peris, D. False blister beetles and the expansion of gymnosperm-insect pollination modes before angiosperm dominance. Pettitt, J. Detection in primitive gymnosperms of proteins and glycoproteins of possible significance in reproduction.

Precipitation reactions occur between components of the ovule tissues in primitive gymnosperms. Pirone-Davies, C. Insights from the pollination drop proteome and the ovule transcriptome of Cephalotaxus at the time of pollination drop production. Poort, R. Zoidogamy in fossil gymnosperms: the centenary of a concept, with special reference to prepollen of late Paleozoic conifers. Poulis, B. Identification of proteins present in the Douglas fir ovular secretion: an insight into conifer pollen selection and development.

Prestianni, C. Tzhorezia veverensis gen. Prior, N. Proteins in Gymnosperm Pollination Drops. Application of proteomics to the study of pollination drops. Ren, D. A probable pollination mode before angiosperms: eurasian, long-proboscid scorpionflies. Science , — Sur le genre Aetheotesta Brongniart. Rothwell, G. Ontogeny of the Paleozoic ovule, Callospermarion pusillum. Evidence for a pollination-drop mechanism in Paleozoic pteridosperms.

Pullaritheca longii gen. Roy, R. Review: nectar biology: from molecules to ecosystems. Ruhfel, B. From algae to angiosperms—inferring the phylogeny of green plants Viridiplantae from plastid genomes. Central Runions, J. Sexual reproduction of Interior spruce Pinaceae. Pollen germination to archegonial maturation. Pollination of Picea orientalis Pinaceae : saccus morphology governs pollen. Rydin, C. Moonlight pollination in the gymnosperm Ephedra Gnetales.

The female reproductive unit of Ephedra Gnetales : comparative morphology and evolutionary perspectives. Said, C. Ovule receptivity and pollen viability in Japanese larch Larix leptolepis Gord.

Silvae Genet. Salter, J. Wettable and unsinkable: the hydrodynamics of saccate pollen grains in relation to the pollination mechanism in the two New Zealand species of Prumnopitys Phil. Saunders, M. Insect pollinators collect pollen from wind-pollinated plants: implications for pollination ecology and sustainable agriculture. Saxton, W. Contributions to the life-history of Actinostrobus pyramidalis. Contributions to the life-history of Tetraclinis articulata Masters, with some notes on the phylogeny of the Cupressoideae and Callitroideae.

Pollination in the Pinaceae, with a special reference to Cedrus atlantica. Schneider, D. Cycads: their evolution, toxins, herbivores and insect pollinators.

Naturwissenschaften 89, — Schwendemann, A. Aerodynamics of saccate pollen and its implications for wind pollination. Serbet, R. Characterizing the most primitive seed ferns. A reconstruction of Elkinsia polymorpha. Seridi-Benkaddour, R. Singh, H. Embryology of Gymnosperms. Smith, S. Aroid seeds from the middle eocene princeton chert Keratosperma allenbyense , Araceae : comparisons with extant Lasioideae. Stewart, W.

A new Pachytesta from Berryville locality of southeastern Illinois. Paleobotany and the Evolution of Plants , 2nd Edn. Cambridge: Cambridge University Press. Strasburger, E. Jenaische Zeitschrift Medizin Naturwissenschaft 6, — PubMed Abstract Google Scholar. Takaso, T. Arnoldia 50, 2—7. Secretions from the female gametophyte and their role in spermatozoid induction in Cycas revoluta.

Effects of ovular secretions on pollen in Pseudotsuga menziesii Pinaceae. Ovulate cone morphology and pollination in Pseudotsuga and Cedrus. Pollination drop and microdrop secretions in Cedrus.

Pollination drop, and pollen capture in Sequioadendron Taxodiaceae. Postpollination-prezygotic ovular secretions into the micropylar canal in Pseudotsuga menziesii Pinaceae.

Pollen movement in the micropylar canal of Larix and its simulation. Significance of exine shedding in Cupressaceae-type pollen. Prefertilization events in the ovules of Pseudotsuga : ovular secretion and its influence on pollen tubes. Tang, W. Insect pollination in the cycad Zamia pumila Zamiaceae. Nectar-like secretions in female cones of cycads. Cycad Newsletter 16, 10— Taylor, T. Pollination biology and reproduction in early seed plants.

London: Academic Press. Terry, I. Odour-mediated push-pull pollination in cycads. Science Thorp, R. Extrafloral nectaries producing rewards for pollinator attraction in Acacia longifolia Andr. Tison, P. Normandie 24, 51— Tomlinson, P. Pollen scavenging. Aspects of cone morphology and development in Podocarpaceae Coniferales. Functional-morphology of saccate pollen in conifers with special reference to Podocarpaceae.

Rescuing Robert Brown-the origins of angio-ovuly in seed cones of conifers. Pollination drop in relation to cone morphology in Podocarpaceae - a novel reproductive mechanism. Contrasted pollen capture mechanisms in Phyllocladaceae and certain Podocarpaceae Coniferales. Vassilyev, A. On the mechanisms of nectar secretion: revisited. Villar, M. Effective pollination period and nature of pollen- collecting apparatus in the gymnosperm, Larix leptolepis.

Micropylar exudates in Douglas fir - timing and volume of production. Ovular secretions in the micropylar canal of larches Larix kaempferi and L. Post-pollination prefertilization drops affect germination rates of heterospecific pollen in larch and Douglas-fir.

Degradome and secretome of pollination drops of Ephedra. Wagner, M. Proteomic evaluation of gymnosperm pollination drop proteins indicates highly conserved and complex biological functions. Wang, D. Structure and function of the neck cell during fertilization in Ginkgo biloba L.

Trees 28, — Wetschnig, W. Pollination biology of Welwitschia mirabilis. Phyton 39, — Wickett, N. Phylotranscriptomic analysis of the origin and early diversification of land plants. Williams, C. Conifer Reproductive Biology.

Williams, J. Pollen tube growth rates and the diversification of flowering plant reproductive cycles. Willson, M. Princeton: Princeton University Press. Xi, Z. Phylogenomics and coalescent analyses resolve extant seed plant relationships.

PLoS One 8:e Xing, S. Ovule development, formation of pollination drop and pollination process in Taxus chinensis Taxaceae. The mechanism of pollination in Platycladus orientalis and Thuja occidentalis. Wind-dispersed fruit are lightweight and may have wing-like appendages that allow them to be carried by the wind. Some have a parachute-like structure to keep them afloat. Some fruits, such as the dandelion, have hairy, weightless structures that are suited to dispersal by wind.

Wind dispersal : Wind is used as a form of dispersal by lightweight seeds, such as those found on dandelions.

Seeds dispersed by water are contained in light and buoyant fruit, giving them the ability to float. Coconuts are well known for their ability to float on water to reach land where they can germinate. Similarly, willow and silver birches produce lightweight fruit that can float on water. Animals and birds eat fruits; seeds that are not digested are excreted in their droppings some distance away. Some animals, such as squirrels, bury seed-containing fruits for later use; if the squirrel does not find its stash of fruit, and if conditions are favorable, the seeds germinate.

Humans also play a major role in dispersing seeds when they carry fruits to new places, throwing away the inedible part that contains the seeds. Seed dormancy allows plants to disperse their progeny through time: something animals cannot do. Dormant seeds can wait months, years, or even decades for the proper conditions for germination and propagation of the species.

Privacy Policy. Skip to main content. Plant Reproduction. Search for:. Pollination and Fertilization. Pollination and Fertilization Plants can transfer pollen through self-pollination; however, the preferred method is cross-pollination, which maintains genetic diversity. Learning Objectives Determine the differences between self-pollination and cross-pollination, and describe how plants have developed ways to avoid self-pollination.

Key Takeaways Key Points Pollination, the transfer of pollen from flower-to-flower in angiosperms or cone -to-cone in gymnosperms, takes place through self-pollination or cross-pollination. Cross-pollination is the most advantageous of the two types of pollination since it provides species with greater genetic diversity. Maturation of pollen and ovaries at different times and heterostyly are methods plants have developed to avoid self-pollination.

The placement of male and female flowers on separate plants or different parts of the plant are also barriers to self-pollination. Key Terms pollination : the transfer of pollen from an anther to a stigma that is carried out by insects, birds, bats, and the wind heterostyly : the condition of having unequal male anther and female stigma reproductive organs cross-pollination : fertilization by the transfer of pollen from an anther of one plant to a stigma of another self-pollination : pollination of a flower by its own pollen in a flower that has both stamens and a pistil.

Pollination by Insects Plants have developed adaptations to promote symbiotic relationships with insects that ensure their pollination. Learning Objectives Explain how pollination by insects aids plant reproduction. Key Takeaways Key Points Adaptations such as bright colors, strong fragrances, special shapes, and nectar guides are used to attract suitable pollinators. Important insect pollinators include bees, flies, wasps, butterflies, and moths.

Bees and butterflies are attracted to brightly-colored flowers that have a strong scent and are open during the day, whereas moths are attracted to white flowers that are open at night.

Flies are attracted to dull brown and purple flowers that have an odor of decaying meat. Nectar guides, which are only visible to certain insects, facilitate pollination by guiding bees to the pollen at the center of flowers. Insects and flowers both benefit from their specialized symbiotic relationships; plants are pollinated while insects obtain valuable sources of food.

Key Terms nectar guide : markings or patterns seen in flowers of some angiosperm species that guide pollinators to nectar or pollen. Pollination by Bats, Birds, Wind, and Water Non-insect methods of pollination include pollination by bats, birds, wind, and water.

Learning Objectives Differentiate among the non-insect methods of pollination. Key Takeaways Key Points Flowers that are pollinated by bats bloom at night, tending to be large, wide-mouthed, and pale-colored; they may also give off strong scents. Flowers that are pollinated by small birds usually have curved, tubular shapes; birds carry the pollen off on their heads and neck to the next flower they visit.

Wind-pollinated flowers do not produce scents or nectar; instead, they tend to have small or no petals and to produce large amounts of lightweight pollen. Some species of flowers release pollen that can float on water; pollination occurs when the pollen reaches another plant of the same species.

Some flowers deceive pollinators through food or sexual deception; the pollinators become attracted to the flowers with false promises of food and mating opportunities. Key Terms food deception : a trickery method employed by some species of orchids in which only bright colors and perfume are offered to their pollinators with no food reward. Double Fertilization in Plants Angiosperms undergo two fertilization events where a zygote and endosperm are both formed.

Learning Objectives Describe the process of double fertilization in plants. Key Takeaways Key Points Double fertilization involves two sperm cells; one fertilizes the egg cell to form the zygote, while the other fuses with the two polar nuclei that form the endosperm.

After fertilization, the fertilized ovule forms the seed while the tissues of the ovary become the fruit. In the first stage of embryonic development, the zygote divides to form two cells; one will develop into a suspensor, while the other gives rise to a proembryo. In the second stage of embryonic development in eudicots , the developing embryo has a heart shape due to the presence of cotyledons. As the embryo grows, it begins to bend as it fills the seed; at this point, the seed is ready for dispersal.

Key Terms double fertilization : a complex fertilization mechanism that has evolved in flowering plants; involves the joining of a female gametophyte with two male gametes sperm suspensor : found in plant zygotes in angiosperms; connects the endosperm to the embryo and provides a route for nutrition from the mother plant to the growing embryo proembryo : a cluster of cells in the ovule of a fertilized flowering plant that has not yet formed into an embryo.

Development of the Seed Monocot and dicot seeds develop in differing ways, but both contain seeds with a seed coat, cotyledons, endosperm, and a single embryo. Learning Objectives Name the three parts of a seed and describe their functions and development.

Key Takeaways Key Points In angiosperms, the process of seed production begins with double fertilization while in gymnosperms it does not. In both monocots and dicots, food reserves are stored in the endosperm; however, in non-endospermic dicots, the cotyledons act as the storage.

In a seed, the embryo consists of three main parts: the plumule, the radicle, and the hypocotyl. In dicots, the hypocotyls extend above ground, giving rise to the stem of the plant, while in monocots, they remain below ground. In dicot seeds, the radicle grows downwards to form the tap root while lateral roots branch off to all sides, producing a dicot tap root system; in contrast, the end of germination in monocot seeds is marked by the production of a fibrous root system where adventitious roots emerge from the stem.

Seed germination is dependent on seed size and whether or not favorable conditions are present. Key Terms testa : the seed coat radicle : the rudimentary shoot of a plant that supports the cotyledons in the seed and from which the root is developed downward; the root of the embryo hypocotyl : in plants with seeds, the portion of the embryo or seedling between the root and cotyledons plumule : consisting of the apical meristem and the first true leaves of the young plant coleoptile : a pointed sheath that protects the emerging shoot in monocotyledons such as oats and grasses.

Development of Fruit and Fruit Types Fruits are categorized based on the part of the flower they developed from and how they release their seeds. Learning Objectives Describe the development of a fruit in a flowering plant.

Key Takeaways Key Points Fruits can be classified as simple, aggregate, multiple, or accessory. Simple fruits develop from a single carpel or fused carpels of a single ovary, while aggregate fruits develop from more than one carpel found on the same flower. Multiple fruits develop from a cluster of flowers, while accessory fruits do not develop from an ovary, but from other parts of a plant.

The main parts of a fruit include the exocarp skin , the mesocarp middle part , and the endocarp inner part ; these three parts make up the pericarp. Dehiscent fruits promptly release their seeds, while indehiscent fruits rely on decay to release their seeds. Key Terms exocarp : the outermost covering of the pericarp of fruits; the skin simple fruit : fruit that develops from a single carpel or fused carpels of a single ovary endocarp : the inner part of the fruit mesocarp : middle part of the fruit accessory fruit : a fruit not derived from the ovary but from another part of the flower.

Fruit and Seed Dispersal Some fruits can disperse seeds on their own, while others require assistance from wind, water, or animals. Learning Objectives Summarize the ways in which fruits and seeds may be dispersed. Seeds dispersed by water are found in light and buoyant fruits, while those dispersed by wind may have specialized wing-like appendages. Humans also play a role as dispersers by moving fruit to new places and discarding the inedible portions containing the seeds.