What Is Vegetative Propagation, Natural Plant Organs Used in Propagation

Vegetative propagation or asexual propagation is the method of reproducing plants with the use of organs other than the seed and spore.

In contrast to sexual propagation, the union of the male and female sexual gametes (fertilization) is not a requisite to the production of new plants.

Hence the word “asexual”, means “without sex” or “not sexual”.

Vegetative Propagation
Bulbs of onion start sprouting

The word “vegetative” refers to plant organs with the exception of the reproductive parts.

In conventional propagation without the employment of tissue culture techniques, asexual propagation is accomplished with the use of roots, stems, and leaves.

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What Is Sexual Propagation and Why Learn Seed Types, Examples of Plants With Recalcitrant Seeds

In conventional methods, sexual propagation is with the use of seeds or spores.

Seeds are used in the spermatophytes or seed-bearing plants while spores are used in the seedless, spore-producing ferns and allies and the bryophytes.

What Is Sexual Propagation
Seeds of jackfruit are recalcitrant and do not require drying before sowing

The descriptive word “sexual” is attached to this type of propagation because the union of the male and female sexual gametes (the process is called fertilization) is a requisite in the production of the seed or in the development of a new plant from a spore.

The certainty of sex in plants was established by Camerarius in 1694 (Poehlman, 1977).

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Why and How Did Gregor Mendel Select the Garden Pea as Experimental Plant?

Gregor Mendel used the common garden pea in his experiments the results of which became the basis of the science of genetics.

It was not by accident that it became his experimental plant.

Even from the start, he was already aware that the right experimental plants must be used in order to avoid the “risk of questionable results”.

Consequently, he developed criteria in the selection of test plants for his study.

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Classifications of Crop Plants According to Natural Methods of Pollination

Familiarity with crop classifications according to the methods of pollination is important in plant breeding.

This is so because of their effect on the applicability of certain breeding methods and techniques.

For example, pureline selection applies to highly self-pollinating crops.

In crop plants with high percentages of natural cross-pollination, controlled selfing is necessary to avoid contamination by foreign pollen.

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Types of Dominance Relations: 1. Complete Dominance

It is now known that there are various types of dominance.

The most popular in Mendelian genetics is complete dominance, but others also exist.

Each of these determines the phenotypic manifestation of a single gene pair in the absence of epistasis or interallelic gene interaction. 

These dominance relations involve intraallelic rather than “interallelic” gene interaction.

The Latin prefix “intra” means within or inside; “inter” means between or among (Borror 1988).

Intraallelic interaction refers to the interaction of alternative alleles within the same gene pair (located in the same locus in the chromosome) as if other gene pairs are absent.

As to the genotype TtGg, this means that the interaction involves that of T with t and of G with g, but not between either T or t with either G or g, or between separate allelic combinations.

Intraallelic interaction, therefore, occurs in the monohybrid which has a single gene pair, or is presumed in a multi-hybrid in which gene pairs are treated separately with the assumption that interlock gene to gene interaction does not exist even if it does.

This is consistent with Mendel’s Law of Independent Assortment which provides that each gene pair acts independently of other gene pairs. 

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Some Commonly Used Terms in Genetics: Review

Familiarization with the common terms in genetics is important in understanding the Mendelian laws or principles, and the role of genetic factors in plant growth and development.

Mendel’s parental “factor” is now referred to by the common term gene.

Gene is probably the most commonly used term in genetics and so deserves more elaboration.

The genes consist of deoxyribonucleic acid or DNA, so-called the chemical basis of heredity.

They are carried in the chromosomes, the physical basis of heredity, within the cell.

The chromosomes are those that appear under magnification as coiled, contracted, threadlike bodies in the nucleus at a certain stage of cell division in diploid somatic cells.

In diploid organisms like humans the chromosomes, and the genes, normally occur in two forms: haploid or singly (1N) in the sexual cells or gametes, and diploid or in pair (2N) in the somatic cells.

Somatic cells refer to the body cells, meaning all cells to the exclusion of the sexual cells or gametes.

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About Water Loss in Plants: Transpiration and Guttation

To be more specific, what is transpiration in plants?

The special reference to plants should be proper and is not without basis. It is because this process is not exclusive to plants.

It also occurs in mushrooms.

This paper and its component pages relate to the kingdom Plantae.

The word is the noun ‘transpire‘ from Latin trans, meaning across or through, and spirare or breathe.

It is the natural process by which liquid water within the plant is converted to gas and, in this state of matter, lost via various aerial organs but primarily through the leaves.

Stated simply, it is the evaporation of water from plants.

Stephen Hales (1677-1761) referred to it as perspiration.

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What Did These Early Researchers Contribute to the History of Photosynthesis?

This is a partial account of the history of photosynthesis.

It covers the period from 1648 when Johann Baptista van Helmont’s Ortus Medicinae was published until about 1900 when the issue on the use of the term ‘photosynthesis’ finally subsided.

The telling is done by way of revisiting the works of selected contributors.

History of Photosynthesis
The light that enters this cave reveals spectacular scenery, the same light from the sun without which there is no photosynthesis in plants and the Earth would have been dark and lifeless

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What Is Photosynthesis, Its Various Functions

What is photosynthesis?

Photosynthesis literally means synthesis (or manufacturing) with light.

It is the physiological process occurring in plants by which carbon dioxide (CO2) and water (H2O), in the presence of visible light and chlorophyll, are converted to organic compounds which store chemical energy.

It also occurs in other chlorophyll-containing organisms such as algae and cyanobacteria.

In 1993, Howard Gest of Indiana University gave the following definition of photosynthesis: Photosynthesis is a series of processes in which electromagnetic energy is converted to chemical energy used for biosynthesis of organic cell materials; a photosynthetic organism is one in which a major fraction of the energy required for cellular synthesis is supplied by light(Gest 2002).

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What Is Climate? What Is Weather, Microclimate, Macroclimate?

It is in relation to plant growth and development that the question What is climate? Is here reviewed.

According to Dr. Frits Went (Went and The Editors of Life, 1963), the climate is the most important environmental factor affecting plant growth and development.

However, any of the various elements that compose climate do not operate singly.

Variation in one of these climatic factors can have significant effects on the others and modify the various physiological processes in plants including photosynthesis, respiration, and transpiration (click here to read Climatic Factors Affecting Plant Growth and Development).

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