Tag: botany

The function of the stomata is to allow water vapor and gases to pass in and out of the leaf. The stomata are also responsible for the process of transpiration, the rate at which a plant loses water. Air enters the plant through the stomata. The air contains carbon dioxide which is used in the photosynthesis process. Then the transpiration and photosynthesis are the main functions of leaves.

Hydrophytes, in which root system is rooted in the soil and their leaves float on the surface of water. In these leaves, stomata are present on the upper epidermis or surface. Such leaves are called Epistomatous leaves. Eg:Nelumbo, Nympheae.

So, the correct option is ‘Upper surface’.

In the vascular bundles of leaves, xylem is situated towards the adaxial or upper epidermis side and phloem is situated towards the abaxial or lower epidermis side.

So, the correct option is ‘lower epidermis’.

Sexual reproduction involves the mixing of genes from two different parents to give offspring with a genetic make-up similar to, but different from, each parent. In Bryophytes the process requires the production of male gametes (sperm), female gametes (eggs) and some means of getting the sperm to the eggs. The gametes are produced on the gametophytes. Water is essential for sexual reproduction in Bryophytes, since it is water that carries the sperm to the egg.

Bryophytes include the various mosses commonly growing in moist shaded areas. Mosses from dense mats on the soil, thus reduce the impact of falling rain and prevent soil erosion.

Bryophytes are the cryptogamae, which do not bear flowers and seeds. They are non-vascular land plants of moist habitat, in which diploid sporophyte lives as a parasite on independent haploid gametophyte. 
Pteridophytes are vascular cryptogams due to the presence of vascular tissues in the plant body.
Gymnosperms and Angiosperms are Phanerogams, which possess flowers and seeds.

In Bryophyta, organs are referred to as "Leaf like' and 'Stem like' and not the true leaf and stem, because leaf and stem have the complex tissues, which perform the water and food conduction. Bryophytes being the lower plants do not have true leaf, stem and roots. They do not have vascular tissue system. 

Bryophytes are non vascular land plants. Fungi and algae belongs to the group Thallophyta, which is the lower plants than Bryophytes on land. Pteridophytes are the first vascular plants on land with all vascular tissues. Since, Bryophytes do not have true leaf, stem and roots, do not have vascular tissues for the water and food conduction, water is absorbed by diffusion process. 

Bryophyta includes the simplest and primitive land plants, which are characterised by the persence of independent gametophyte and parasitic sporophyte. They are non-vascular land plants with undifferentiated plant body. the plant body is not divided into true leaves, stem and roots. In all bryophytes the ecologically persistent, photosynthetic phase of the life cycle is the haploid, gametophyte generation rather than the diploid sporophyte; bryophyte sporophytes are very short-lived, are attached to and nutritionally dependent on their gametophytes and consist of only an unbranched stalk, or seta, and a single, terminal sporangium. 

Bryophytes are also called as the amphibians of the plant world due to their preference for moist habitat and dependence on water for fertilization, despite being land plants.