The following Topics and Sub-Topics are covered in this chapter and are available on MSVgo:
You must have also seen that all the plants have different leaves, like mangoes and neem. The leaves of mango trees are joined to a stem via petiole. These types of leaves are called simple leaves. While leaves of neem have several leaflets attached to the stem via the petiole. These leaves are called compound leaves.
Observe banana leaf and mango leaf; you can easily see the difference in the patterns present on them. This pattern in the veins of the leaves is termed venation, and it helps in the distinction of plants. Banana is a monocot plant, depicting parallel venation where veins of the leaves are arranged parallel to each other. In contrast, mango is a dicot plant with reticulate venation in which the veins of the leaves are placed in the form of a network.
You might have heard that leaves are called the kitchen of the plant. The reason is that they prepare the food for plants using carbon dioxide and water in the presence of sunlight by the process of photosynthesis.
Plants release oxygen as a product of photosynthesis, which is then inhaled by other living organisms. This is how plants sustain life on earth.
Along with this, leaves carry out transpiration or remove excess water from the plant body by evaporation. In the epidermis part of the leaves, the exchange of gases and water molecules takes place.
You might have heard about some plants that eat other organisms. Though these plants can perform photosynthesis, they still need some more nutrition. Such plants which derive their nutrition by trapping other insects and consuming them are called insectivorous plants. Examples are Venus flytrap, Pitcher plants, etc.
If you look at the leaves of Bryophyllum, you will see some buds at the ends of the leaves. These buds, after falling on the ground, will germinate to give rise to a new plant. Such a type of asexual mode of reproduction shown by some plants is termed Vegetative Propagation in the leaf.
You might have seen a variety of plants in your surroundings with beautiful flowers. These flowers have four whorls or parts. Look at a China Rose, also called the Hibiscus flower. It has a green structure at the base; it is termed as sepal. The pretty red-coloured part of the flower attracts many insects towards it and is called petal. This flower has a male reproductive part known as stamen (containing anther and filament), and a female reproductive part called carpel (containing stigma, style, and ovary).
Have you ever wondered how fruit comes on the guava or mango tree? When the pollen grains from the anther of the stamen reaches the stigma, pollination takes place. If this occurs in the same flower, it is called self-pollination, and if the process takes place in different flowers, it is called cross-pollination. Air, water, and insects carry pollen from one flower to another.
The process of fusion of the male gamete (inside the pollen grain) to the female gamete (inside the ovary) is called fertilization. As a result of fertilization, a zygote is formed inside the seed. It is single-celled initially, but it, later on, undergoes cell division and forms a plant.
After fertilization, the ovary changes into fruit, and the zygote divides into the embryo, which is present inside the seed of the fruit. Take a kiwi or mango and cut that in two halves without peeling them off. The outermost layer which covers the fruit is called epicarp. The inner, fleshy, juicy middle part that you eat is termed mesocarp. The innermost layer in the fruit that surrounds the seed is called the endocarp.
You know that if you sow the seed, it will give rise to a new plant. The zygote develops into an embryo inside the seed. The part of the embryo which gives rise to the shoot is called plumule, while the part giving rise to the root is termed radicle. Cotyledon present in the seed provides nutrition to the growing embryo. Monocot plants (like corn) have one cotyledon in the seed, while dicot plants have two cotyledons in the seed (like pea, gram).
The seed remains dormant in the soil for some time. After getting enough water and heat through sunlight, it germinates and gives rise to a plantlet. Different seeds have varying requirements during the germination process. This plantlet further grows into a plant and then a tree.
There is a lot that you have learned about plant life, leaves, flowers, fruits, and seeds. To know about plant life further, you can download the MSVgo app, which offers a large base of learning videos, quizzes, interactive games, and many more to the students from grade 6 to grade 12.