Skip to content
Home » Plant Organ System and Their Functions

Plant Organ System and Their Functions

  • Botany

In this plant organ system and their functions post we have briefly explained about plant characteristics, plant organ system (root, shoot) and functions, types of plants. 

Plants are multicellular organisms in the order Plantae that produce their own sustenance through photosynthesis. There are about 300,000 plant species, with grasses, trees, and shrubs being notable examples. Plants play a crucial part in the global ecology. They are crucial in the food chain because many species eat plants or eat organisms that eat plants, and they create the majority of the world’s oxygen. Botany is the scientific study of plants.

Plant Characteristics

Autotrophs are plant organisms that make their own sustenance. They do it through photosynthesis, which is the process of turning light energy and carbon dioxide into nutrients like sugars.

Photosynthesis takes place in chloroplasts, which are cell organelles that contain chlorophyll and carotenoids, which absorb light energy and convert it to a useful form. Heterotrophs, on the other hand, are organisms that are unable to produce their own food and must rely on the consumption of other organisms in order to survive. Plants are eaten by many heterotrophs. 

Animals that have eaten plants are eaten by other heterotrophs. Plants are primary producers in many ecosystems, ensuring the survival of a variety of other organisms. Furthermore, oxygen is produced as a consequence of photosynthesis, and many species rely on it to exist. Plants are essential to our survival. Plants have eukaryotic cells and are multicellular organisms. A eukaryotic cell is a rather big cell having a functional nucleus and other organelles. Eukaryotic cells can be found in plants, protists, fungi, and mammals. 

Cell walls containing cellulose, chloroplasts that produce photosynthesis, and a big central vacuole that retains water and keeps the plant turgid are all characteristics of plant cells. rokaryotic cells, on the other hand, are tiny and lack a real nucleus or organelles other than ribosomes, which are responsible for protein synthesis. Prokaryotic cells are found in bacteria and archaea.

Vascular tissue, such as xylem and phloem, is found in many plants and transports water and nutrients throughout the plant organisms. This is especially crucial for upward-growing plants since water must move from the roots up the stem to the leaves.  Plants that are more “complex” have more vascular tissue. Plants are said to have descended from algae-like forefathers. Today, most algae are categorised as bacteria rather than plants.

Green algae, on the other hand, are commonly lumped in with plant organisms since they have cellulose in their cell walls and photosynthesising chloroplasts. plant organisms reproduce both sexually and asexually, and they have generations that alternate. A haploid stage and a diploid stage alternate. When cells have one pair of chromosomes, they are called haploid; when they have two sets, they are called diploid. (Humans are diploid, but their gametes (sperm and eggs) are haploid.) 

Two haploid gametes combine to produce a diploid zygote in plants. Mitosis is the process by which a diploid zygote divides into a multicellular creature. It’s called a sporophyte, and it generates haploid spores asexually as it matures. The haploid spores subsequently develop into gametophytes, which are multicellular organisms. The alternating between diploid and haploid begins anew when gametophytes create haploid gametes, which merge to form a diploid organism.

Plant Organ System and Their Functions

Plants, like animals, are multicellular eukaryotes with organs, tissues, and cells that perform highly specialised activities. The following diagram depicts the links between plant organ system, tissues, and cell types.

Stems and leaves make form the shoot system. Each organ contains all three types of tissue (roots, stems, and leaves) (ground, vascular, and dermal). Each tissue type is made up of several cell types, and the function of the tissue it contains is determined by the structure of each cell type.

Plant Organ Systems

Plant Organ System and Their Functions

A shoot system and a root system are two separate organ systems in vascular plants. Stems, leaves, and reproductive components of the plant make up the shoot system (flowers and fruits). The shoot system grows mostly above ground, absorbing the light required for photosynthesis. Typically, the root system, which supports the plants and absorbs water and minerals, is underground. A typical plant’s organ systems are depicted here.

The Root

Plant Organ Systems

Seed plants’ roots have three primary functions: attaching the plant to the earth, absorbing water and minerals and transferring them upwards, and storing photosynthetic products. Some roots have been altered such that they can absorb moisture and exchange gases. The majority of the roots are found underground. Some plants, on the other hand, have adventitious roots that develop from the shoot above earth.

The shoot

Stem

Stems are an element of a plant’s shoot system. Their primary purpose is to maintain the plant by holding leaves, blooms, and buds. They also connect the roots to the leaves, delivering absorbed water and nutrients from the roots to the rest of the plant and sugars from the leaves (photosynthesis site) to preferred sites throughout the plant. They might be a few millimetres long or hundreds of metres long, and their diameter varies depending on the plant variety. Although the stems of some plant organisms, such as the potato, develop underground, they are normally above ground.

leaves

Photosynthesis, the process by which plant organisms create food, takes place mostly on leaves. The presence of chlorophyll in the leaf cells causes most leaves to be green. Other plant pigments may obscure the green chlorophyll in some leaves, resulting in a variety of colours.

The structure of a typical eudicot leaf is depicted below. A petiole connects typical leaves to the plant stem, although there are other leaves that attach directly to the stem. Veins in the leaf carry vascular tissue (xylem and phloem), which also give structural support.

Types of Plants

Charophytes

Stoneworts are charophytes, which are complex green algae. They have chloroplasts in their cells, cellulose in their cell walls, and the ability to store starch, just like plants. They reproduce sexually, and some of their sperm include flagella (moving tails), just as some plants. Some fossil stoneworts resemble modern-day stoneworts quite closely.

Bryophytes

Nonvascular terrestrial plant organisms are known as bryophytes. They are lacking in vascular tissue, which distributes water and nutrients. They can be found on land as well as in water. Mosses, liverworts, and hornworts are all examples of bryophytes. Bryophytes are similar to algae in that they do not have a vascular system. They have elements that resemble roots, stems, and leaves, but they are not the same as those found in vascular plants. Liverworts are thought to be the first land plants to appear. Hornworts exhibit characteristics of both algae and plants, while mosses, the most well-known bryophytes, are the most closely related to vascular plants.

Vascular Plants

Embryos produced by seedless vascular plant organisms are not protected by seeds. Instead, spores are used to replicate. Ferns, horsetails, quillworts, clubmosses, and spikemosses are all members of this category. Pteridophytes was the old name for these plant organisms, however it turned out that this was an incorrect classification because ferns and horsetails are more closely related to seed plants than quillworts, clubmosses, and spikemosses. During the Devonian period and in Carboniferous woods, seedless vascular plants thrived.

Gymnosperms

Conifers and allied plant organisms such as ginkgoes and cycads are examples of gymnosperms. Gymnosperms have “naked seeds,” meaning they don’t have an ovary like blooming plants. Instead, they produce seeds on the surface of leaves or, in the case of conifers, modified structures such as cones. The pine tree and its cones are probably the most well-known gymnosperm. Ginkgoes are also noted for remaining virtually unmodified from ancient ginkgo plants discovered in 270 million-year-old fossils.

Angiosperms

Angiosperms are flowering plants. They are the most widespread plant organisms today, and over 295,000 different species are known. Their reproductive organs are flowers, which have male parts like stamen and pollen, and female parts like the pistil. When flowers are pollinated, fruits develop containing seeds. Angiosperms have more complex vascular tissue than gymnosperms do.

Further Readings

Reference