Biological Sciences
Plants Reproduction
Plant reproduction involves the process by which plants produce offspring. It can occur through sexual reproduction, involving the fusion of male and female gametes, or asexual reproduction, where new plants are generated from vegetative parts. Sexual reproduction in plants often involves the production of flowers, pollination, and the development of seeds and fruits.
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12 Key excerpts on "Plants Reproduction"
- Shoichi Kawano(Author)
- 2012(Publication Date)
- Academic Press(Publisher)
BIOLOGICAL APPROACHES AND Copyright © 1990 Academic Press Limited EVOLUTIONARY TRENDS IN PLANTS ISBN 0-12-402960-4 All rights of reproduction in any form reserved 274 K. M. Urbanska II. Reproduction in the Angiosperms - Different Ways and Means, the Same Effect Reproduction has a very special place amongst the basic functions of a live organ-ism: it secures the formation of the offspring. Reproductive behaviour of flowering plants is frequently characterized both by sexual and asexual processes, and influ-enced not only by genetic make-up but also phenotypic plasticity. All these differ-ences notwithstanding, a successful reproduction has but one outcome viz. the ap-pearance of active descendants contributing to the population turnover. The essential role of reproduction has been recognized in the numerous defini-tions which identify the reproductive process with the formation of new individu-als, but some authors still emphasize the production of propagules rather than the appearance of the new plants (Table 1). Last but not least, some scientists (e.g. Grime, 1979) renounce the term reproduction and propose to replace it by regeneration, whereas others (e.g. Harper, 1977) limit the reproduction to some specified conditions (Table 1). TABLE 1 Some definitions of reproduction Definition Authors) Ability of organism to produce new individuals of the same kind; this process is essential to preservation of species. Hartmann, 1959 Reproduction involves the formation of a new individual from a single cell; this is usually (though not always, e.g. apomicts) a zygote. In this process, a new individual is reproduced by the information that is coded in all that cell. Harper, 1977 Production of sexual or asexual propagule which starts a new developmental cycle and a new organism.
eBook - PDF- Rajesh Singh(Author)
- 2020(Publication Date)
- Delve Publishing(Publisher)
Similarly, the vegetative method has different sub -methods like cutting, budding, layering, separating, and grafting which are being used for producing the new plant which is similar to their parent plant. The sexual reproduction process takes place through pollination. Pollination is a process known as the sexual process which is used by the plants for reproduction. In this method, there is an involvement of male and female gametes that fuses together to form a new plant through an embryo. There are typically two types of pollination methods like self-pollination and cross-pollination which is being explained in detail. 2.1. INTRODUCTION Reproduction is a process that takes place in order to produce the new offspring in the plants. Therefore, the reproduction process is required for the generation of new individuals. Plants that are present on the land are considered to have asexual reproduction process, where the offspring are found to be genetically identical to their parents or sexual by creating a genetic variation. The life cycle of the plants basically involves two alternating generations: sporophytes that are making the spores and the gametophyte that is producing the make and the female gametes. During the evolution in the land plant, the life cycle has been altered from the gametophyte generation. It is observed that the structure that is making the gametes and spores, and the way through which the reproductive cells are being exchanged and dispersed. It also becomes altered, as the plants become to adapt the living in the drier environments. Flowers are representing the reproductive organ of the flowering plants and considered to be very important for the identification as it is typically providing the characters that are steadily being expressed within a taxon. Plant Reproduction 31 This is because the floral characteristics are basically under strong genetic control and it is not affected by the changes in the environments.
eBook - ePub- Charles Adams, Mike Early, Jane Brook, Katherine Bamford(Authors)
- 2015(Publication Date)
- Routledge(Publisher)
4CHAPTERLevel 3Plant reproduction
Figure 4.1 Bees and other pollinating insects are attracted to large, colourful fl owers. The Iris shown has blue fl owers, a colour attractive to bumble bees, and tepals which can support the bee’s weight with nectar guides directing the bees towards nectaries at their baseThis chapter includes the following topics:• Inflorescence types• Pollination syndromes• Cross- and self-pollination mechanisms• The relevance of cross-and self-pollination to horticulture• Fertilization• Seed structure – endospermic and non-endospermic seeds• Seed dormancy• Seed quality – testing and treatments• Seed provenance and conservation• Fruit development, structure and classification• Asexual reproduction and vegetative propagationPrinciples of Horticulture. 978-0-415-85909-7 © C.R. Adams, M.P. Early, J.E. Brook and K.M. Bamford. Published by Taylor & Francis. All rights reserved. Figure 4.2 Inflorescences which are designed to maximize pollen dispersal and capture: (a) in a Betula (birch) left, female catkins; right, male catkins; (b) in grassesReproduction is the process by which new individuals are formed and hence the species is perpetuated. In plants this can be asexual, by means of a range of vegetative structures or it can be sexual resulting in seeds. Sexual reproduction has two key advantages for the plant. It gives rise to variation in a plant's offspring, enabling it to withstand environmental pressures and it also provides the means by which plants can colonize new areas, through dispersal of seeds, often enclosed within a fruit. Although plants produced from seed are genetically variable and will not be uniform in their growth and other characteristics such as size, flower colour etc., this variation can be controlled by skilled plant breeders (see F1 hybrids p. 47
eBook - PDFAdvanced Plant Production NQF4 SB
TVET FIRST
- W Burger(Author)
- 2013(Publication Date)
- Macmillan(Publisher)
Natural plant propagation Overview In this module you will: • explain asexual plant propagation methods with examples • explain sexual plant propagation methods including pollination and fruit setting. Introduction Production of food – vegetables, fruit, cereals and fibre (such as cotton) – can only happen if the plant is able to reproduce. You must have noticed that under natural conditions, plants reproduce themselves. There are two main methods of reproduction or propagation in nature. These methods are sexual reproduction and asexual reproduction. In nature, flowers develop on plants as a result of pollination and fertilisation. Pollen is carried by wind, water or animals (mainly insects). The pollen grain is transferred from the male flower to the female flower. This is sexual reproduction as it involves a male and a female. But in nature you will also find that some plants reproduce through root development from various parts of the plant, i.e. the vegetative parts. We call this kind of plant reproduction asexual or vegetative reproduction. During domestic plant production practices, the farmer uses the same basic principles of plant propagation that are found in nature – the farmer will use seeds for sexual reproduction of plants or will use vegetative parts of the plant for asexual production. 2 Module 1 Module 1 Propagation: reproducing or making more of the same Sexual reproduction: in a plant, sexual reproduction happens when pollen is transferred from the anthers onto the stigma of a flower in a process called ‘pollination’ Asexual reproduction: in a plant, asexual reproduction takes place through the non-reproductive or vegetative parts of a plant, e.g. the roots, stems and leaves Pollination: to transfer pollen from the anthers to the stigma of a flower Vegetative: the non-reproductive parts of a plant, e.g. the roots, stems and leaves Words & Terms
eBook - PDF- Singh, Pradeep Kumar(Authors)
- 2021(Publication Date)
- Daya Publishing House(Publisher)
There are finer differences in these types. For example, there may be differences between the time of pollen shed and stigma receptivity. This ebook is exclusively for this university only. Cannot be resold/distributed. 3. Self-fertilization versus cross-fertilization: Just because a flower is successfully pollinated does not necessarily mean fertilization will occur. The mechanism of self-incompatibility causes some species to reject pollen from their own flowers, thereby promoting out crossing. 4. Sexuality versus asexuality: Sexually reproducing species are capable of providing seed through sexual means. Asexuality manifests in one of two ways – Vegetative reproduction (in which no seed is produced) Or Agamospermy (in which seed is produced). TYPES OF REPRODUCTION Plants are generally classified into two groups based on mode of reproduction as either sexually reproducing or asexually reproducing. Sexually reproducing plants produce seed as the primary propagules. Seed is produced after sexual union (fertilization) involving the fusion of sex cells or gametes. Gametes are products of meiosis and, consequently, seeds are genetically variable. Asexual or vegetative reproduction mode entails the use of any vegetative part of the plant for propagation. Some plants produce modified parts such as creeping stems (stolons or rhizomes), bulbs, or corms, which are used for their propagation. Asexual reproduction is also applied to the condition whereby seed is produced without fusion of gametes (called apomixis). It should be pointed out that some plants can reproduce by either the sexual or asexual mode. However, for ease of either propagation or product quality, one mode of reproduction, often the vegetative mode, is preferred. Such is the case in flowering species such as potato (propagated by tubers or stem cuttings) and sugarcane (propagated by stem cuttings).
eBook - PDF- Francisco Pugnaire, Fernando Valladares, Francisco Pugnaire, Fernando Valladares(Authors)
- 2007(Publication Date)
- CRC Press(Publisher)
(2005) to explore this topic further. The paternal side of plant reproduction is increasingly receiving more attention in studies of reproductive success, and here we synthesize existing information on this subject, giving some directions for future research. For further readings about plant reproductive strategies and breeding systems we recommend Richards (1997) and de Jong and Klinkhammer (2005). Finally, we briefly review studies on the influence of pollinators on the evolution of floral traits and diversification of angiosperms. ASEXUAL REPRODUCTION Asexual reproduction is fairly common in plants and allows them to persist in their habitats with complete independence of pollinating vectors. Two types are distinguished, both quite similar from the genetic viewpoint, although their mechanisms are different: (a) vegetative reproduction, that is, asexual multiplication of an individual (genet)—which has originally arisen from a zygote—into physiologically independent units (ramets) (Harper 1977, Abrahamson 1980) and (b) agamospermy, the production of fertile seeds without sexual fusion of gametes. Advantages of asexual reproduction include the possibility to exploit larger areas and new locations, provided that vegetative propagules are widely dispersed (Janzen 1977, Lovett Doust 1981), and the preservation of successful genotypes since they are not lost during sexual recombination, which would be the case for example during heterozygote advantage (Peck and Waxman 1999). In many perennial plants, both asexual and sexual reproduction take place, the latter usually occurring once a growth threshold has been attained (e.g., Weiner 1988, Schmid and Weiner 1993, Worley and Harder 1996).
eBook - PDF- Mary Ann Clark, Jung Choi, Matthew Douglas(Authors)
- 2018(Publication Date)
- Openstax(Publisher)
32 | PLANT REPRODUCTION Figure 32.1 Plants that reproduce sexually often achieve fertilization with the help of pollinators such as (a) bees, (b) birds, and (c) butterflies. (credit a: modification of work by John Severns; credit b: modification of work by Charles J. Sharp; credit c: modification of work by "Galawebdesign"/Flickr) Chapter Outline 32.1: Reproductive Development and Structure 32.2: Pollination and Fertilization 32.3: Asexual Reproduction Introduction Plants have evolved different reproductive strategies for the continuation of their species. Some plants reproduce sexually, and others asexually, in contrast to animal species, which rely almost exclusively on sexual reproduction. Plant sexual reproduction usually depends on pollinating agents, while asexual reproduction is independent of these agents. Flowers are often the showiest or most strongly scented part of plants. With their bright colors, fragrances, and interesting shapes and sizes, flowers attract insects, birds, and animals to serve their pollination needs. Other plants pollinate via wind or water; still others self-pollinate. 32.1 | Reproductive Development and Structure By the end of this section, you will be able to do the following: • Describe the two stages of a plant’s lifecycle • Compare and contrast male and female gametophytes and explain how they form in angiosperms • Describe the reproductive structures of a plant • Describe the components of a complete flower • Describe the development of microsporangium and megasporangium in gymnosperms Sexual reproduction takes place with slight variations in different groups of plants. Plants have two distinct stages in their lifecycle: the gametophyte stage and the sporophyte stage. The haploid gametophyte produces the male and female gametes by mitosis in distinct multicellular structures. Fusion of the male and females gametes forms the diploid zygote, which develops into the sporophyte.
eBook - ePub- Peter Scott(Author)
- 2013(Publication Date)
- Wiley-Interscience(Publisher)
Longevity . Plants may, in many instances, be long-suffering and long-lasting, but if the great extinctions of the past teach us anything, it is that nothing lasts forever. No matter how old an individual plant is, one day conditions will change to make survival impossible. Plants need some means of surviving such adverse conditions, which may be local or temporary, and reproduction can offer a solution to this. Clonal plants may move away from the point of origin of the mother plant and therefore widen the spread of the plant, thereby escaping a particular stress. In addition, seeds offer even greater opportunities to disperse genetic material well away from the parent plant and also provide a structure that can remain dormant over prolonged periods. This permits a plant to survive temporary changes in conditions. Clones or seeds also produce new individuals which are free from fungal infections or damage present in the parent plant.3. Genetic variation . Finally, reproduction offers opportunities for genetic variation, which is essential in a changing habitat. Asexual reproduction offers little opportunity for genetic variation but the potential from sexual reproduction is immense.In this chapter we will look in greater detail at how plants reproduce and the merits and limitations of the different methods.Asexual reproduction
Many plant species use asexual reproduction as a means of propagation. Asexual reproduction has several advantages and disadvantages (Figure 9.1 ). This form of reproduction produces individuals that are genetically identical and does not support much scope for phenotypic variation. This can lead to plants being vulnerable to changes in the habitat. In addition, offspring are generated close to the parent plant, so parent and offspring often have to compete for nutrients and light. However, asexually produced plants usually attain adulthood in advance of seedlings of the same parent and hence rapidly out-compete neighbouring plants reliant on seeds. Under many conditions, asexual reproduction is more successful than sexual reproduction for plants and a large number of species use this as their sole means of reproduction.Figure 9.1 Asexual reproduction in plants. Plants possess a range of different means of asexual reproduction. (A) Apomixis: using this method, the flowers spontaneously produce seeds without the need for any fertilization. The actual source of the embryo can come from the egg cell or the cells surrounding it. (B) A hyacinth bulb (Hyacinthus hybrid); bulbs frequently produce bulbils (small offset bulbs) at the base of the bulb. (C) A gladiolus corm (Gladiolus hybrid); corms frequently produce small offset corms at the base of the stem. (D) Strawberry plant (Fraxinus hybrid), forming runners, modified stems that form new plants. (E) Black poplar (Populus nigra
- Caula A. Beyl, Robert N. Trigiano, Caula A. Beyl, Robert N. Trigiano(Authors)
- 2016(Publication Date)
- CRC Press(Publisher)
65 5 Sexual Reproduction and Breeding Timothy A. Rinehart, Robert N. Trigiano, Phillip A. Wadl, and Haley S. Smith In this second edition of Plant Propagation Concepts and Laboratory Exercises , we have combined the first edition Chapters 36, “Sexual Reproduction in Angiosperms,” and 37, “Breeding Horticultural Plants,” into this single chapter, “Sexual Reproduction and Breeding.” These top-ics are so closely related that we believe that concepts are best presented as one unit. In addition to combining the aforementioned chapters, we have added some high-resolution microscopic photographs of mitotic events that are comparable to the line drawings depicting the vari-ous phases of mitosis. We have maintained some black-and-white figures for clarity of presentation. Lastly, we have included in this edition a simple laboratory exer-cise involving the observation and frequency of mitotic phases in the cells of onion as seen in longitudinal sec-tions of root tips on prepared slides. Many horticultural crops are produced exclusively by vegetative or asexual means. Asexual reproduction using grafting, rooted cuttings, and various other meth-ods ensures clonal fidelity of a cultivar. Phenotypic and genetic variation in these crops is undesirable, especially if the consumer is expecting to purchase a plant that they have seen growing somewhere else or pictured in a catalog. For example, all Cornus florida L. (flowering dogwood) ‘Cherokee Sunset’ plants have yellow variegated leaves and pink bracts subtending the floral disk, and are produced exclusively by a grafting technique (Chapter 25). There is little variation using this technique, and it produces Concept Box 5.1 • Most plants exhibit alternation of generations. In this case, the plant generations are the sporophytic or diploid (2n) phase that produces spores and the gametophytic or haploid (n) phase that produces gametes. • The four parts of flowers are sepals, petals, anthers, and pistils.
eBook - PDF- Emea, N(Authors)
- 2018(Publication Date)
- Agri Horti Press(Publisher)
210 Essentials of Plant Breeding 12 Plant Reproduction The plant kingdom is divided into many classes and divisions. In 1883, Eichler separated the plant kingdom (Plantae) into two subkingdoms, the first being Cryptogamae (bacteria, algae, fungi, molds, liverworts, moss and ferns); the second being Phanerogamae (including gymnosperms and angiosperms). There have been many changes to the classification system, as we learn more about the genetics of different species. More recent taxonomy created new kingdoms that separated fungi, algae, and molds from what we commonly consider as plants. Plantae was separated into two divisions: Bryophytes (non-vascular) and Tracheophytes (vascular). Of the vascular plants, angiosperms (the flowering plants) make up approximately 300,000 of the 312,000 known number of living species. The number of 312,000 is probably a gross under-estimation. For anyone interested there is an estimated 20,000 species of non-vascular plants. There are many different methods of reproduction that plants have developed over the centuries. If a plant’s method of reproduction makes it easier to cross species or hybridized, it is more likely that its offspring will be better adapted to a changing environment For more than 8,000 years, human beings have also been affecting plant development by purposefully breeding new characteristics into plants, creating new species. The most important fact regarding reproduction is that every living organism has, in its cell’s nucleus, a set of chromosomes. Chromosomes carry genes that have all the information necessary to make new individual organisms. This ebook is exclusively for this university only. Cannot be resold/distributed. Plant Reproduction 211 DIAGRAM OF A DICOT PLANT One of the simplest methods of reproduction is when one cell divides and becomes two equal halves that will grow large enough to split again. With plants and animals that reproduce this way, each generation is identical to the one before.
eBook - PDF- William F. Grant(Author)
- 2013(Publication Date)
- Academic Press(Publisher)
Reproductive plant strategies may accordingly be quite distinct from those involved in the established nonreproductive phase (see e.g. Grubb 1977). Moreover, features that increase e.g. seed survival are not necessarily advantageous for survival of seedlings or very young plants (Grime 1978; Fossati 1980; Sarukhan 1980). It follows that only rarely can the environmental unpredictability be assessed by data referring to a single life phase (e.g. Wilbur 1976). As well formulated by Abrahamson (1980), the function of reproduction is to perpetuate parental genes in time and space; they are carried by descendants forming a new generation in the demographic sense. Survival and dispersal represent thus important aims in plant reproductive strategies. Seeds serve these purposes very well; their dormancy and increased longevity may represent successful adaptations to the unpredicta- bility of environment (Levins 1969; Harper 1976; Cook 1980). It should be emphasized, however, that seed production is not to be automatically associated with sexual mechanisms and recombination. We stress this point for there still is a great deal of confusion on the subject, even in some recent reviews (e.g. Williams 1975, PLANT REPRODUCTIVE STRATEGIES 225 in particular the comparison between sexual and asexual offspring; see also Abrahamson 1980)· Plants in which seed production results from polarized segregation admittedly represent a small and exceptional group (Cleland 1962; Smith-White 1948, 1955; Täckholm 1922; Urbanska 1977a, 1980a)· On the contrary, there is nothing so exceptional about the numerous agamospermous taxa; they frequently have high fecundity rates, often display some other forms of asexual reproduction and apparently are able to cope well with environmental hazards· Biological functions viz.
No longer available |Learn more- Azhar ul Haque Sario(Author)
- 2023(Publication Date)
- tredition(Publisher)
Genetic Potluck Party: Cross-pollination is like plants sharing their genetic gifts at a big party. Pollen from one plant fertilizes another, leading to babies with a mix of features. This genetic diversity gives these plants a bigger set of traits to work with, like having a full wardrobe for all seasons.Ready for Surprises: Plants that cross-pollinate are better at dealing with unexpected changes. They have a wide variety of genetic traits, so there's a better chance some of them will cope with new diseases or environmental shifts. It's like having a tool for every job that might come up.Relying on Pollinator Buddies: These plants depend on friends like bees and birds to move pollen. They have a special relationship with these pollinators, but if their pollinator pals are in trouble, so are they. It's like needing a friend to lend you a tool – if they don't show up, you're stuck.In Summary:Both self-pollination and cross-pollination have their ups and downs. Self-pollination offers simplicity and independence but limits genetic variety and adaptability. Cross-pollination brings a rich mix of genes, which is great for adapting to new situations, but it also means these plants need pollinators to thrive. How a plant reproduces is a big deal, influencing how it deals with life's challenges and opportunities.In the intricate journey of plant reproduction, the growth of the pollen tube and its subsequent entry into the ovule, leading to fertilization, is a fascinating process. This natural event is key to the development of seeds in flowering plants. Let's explore this process in simple, yet detailed terms.1. The Pollen Grain's Arrival: The story begins when a pollen grain, the male reproductive unit of a flower, lands on the stigma of a pistil – the female part of another flower. The stigma is often sticky, helping the pollen grain to adhere.2. Germination of the Pollen Grain: Once securely positioned, the pollen grain undergoes a transformation. It germinates, which means it starts to grow. This growth is fueled by the nutrients present in the pollen.3. Formation of the Pollen Tube: The germinated pollen grain forms a thin, tubular structure called the pollen tube. This tube is like a microscopic tunnel, and it has a crucial mission: to transport the male genetic material to the female ovule.
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