Tag: botany

Broad part of leaf is lamina. The lamina is the expanded portion of a leaf and it is specialized for photosynthesis. For this purpose, a leaf is typically flat and thin, to expose the chlorenchyma to light over a broad area and to allow light to penetrate fully into the tissues. 
Thus, the correct answer is option C.

Exogenous, flattened, green, lateral appendages arising from nodes of the stem or branches in acropetal succession are called as leaves. Leaves arise from shoot apical meristem and bear buds in their axils and help in assimilation of food, exchange of gases and transpiration. So, leaf is a lateral outgrowth of stem.  

• During fertilization of Funaria, the ventral canal cell and the neck canal cells of the archegonium dis­integrate forming a mucilaginous substance. This mucilaginous substance absorbs water accu­mulated as rain or dew water, then swells up and the resultant pressure breaks apart the terminal cover cell. Now sugar containing mucilaginous substances ooze out through the opening of the archegonial neck.
• The liberated antherozoids are now attrac­ted chemotactically towards the archegonia. Large numbers of antherozoids enter the neck, but only one of them fuses with the egg nucleus to form the diploid zygote.
  
• Hence In Funaria, archegonia attract antherozoids by 'Sucrose / Sugar '.
• So, the correct answer is 'Sucrose / Sugar '.

• Node: The leaves arise in the regions of the plant known as the plant nodes and are therefore the point of attachment of the leaves. 
• The region of the plant between two nodes is known as the internode.
•  The angle between the upper surface of the leaf and the stem from which it arises is known as the axil. 
• The petiole is the stalk which attaches the leaf to the stem. 

leaf is a green outgrowth of a stem. It performs photosynthesis and provides food to the rest of the plant body. There are different types of leaves found due to climate, water availability, etc. A leaf consists of lamina and petiole, leaves can be monocot or dicot. It contains stomate which helps in gaseous exchange.

A lenticel is a porous tissue consisting of cells with large intercellular spaces in the periderm of the secondarily thickened organs and the bark of woody stems and roots of dicotyledonous flowering plants. It functions as a pore, providing a pathway for the direct exchange of gases between the internal tissues and atmosphere through the bark, which is otherwise impermeable to gases. A hydathode is a type of secretory tissue in leaves, usually found in angiosperms, that secretes water through pores in the epidermis or margin of leaves, typically at the tip of a marginal tooth or serration.
Hydathodes are mainly found in aquatic plants and in some herbaceous plants growing in moist places.
A stoma (plural stomata) is a pore, found in the epidermis of leaves, stems and other organs that is used to control gas exchange.
Aerenchyma is the spaces or air channels in the leaves, stems and roots of some plants, which allows exchange of gases between the shoot and the root.
Thus, the correct answer is option A.

Marginal meristem is the meristem located along the margin of a leaf primordium and forming the leaf blade. The apical meristem or growing tip, is a completely undifferentiated meristematic tissue found in the buds and growing tips of roots in plants.
Intercalary meristems are capable of cell division, and they allow for rapid growth and regrowth of many monocots. Intercalary meristems at the nodes of bamboo allow for rapid stem elongation, while those at the base of most grass leaf blades allow damaged leaves to rapidly regrow.
In mass meristem the cells divide in all planes to form bulk of tissue. this type of meristem takes part in the formation of cortex, pith, endosperm and sporangia.
Therefore, the correct answer is option D.

A hydathode is a type of secretory tissue in leaves, usually found in angiosperms, that secretes water through pores in the epidermis or margin of leaves, typically at the tip of a marginal tooth or serration. 

• A leaf is said to be hypostomatous where stomata are present on abaxial surface only (lower surface). Most tree species of dicotyledons possess such leaves. Ex. Ficus, Nerium etc.
• Hypostomatous plants are non-aquatic plants in which stomata are present on the lower surface because their function is to regulate the amount of water in the leaf and being on the bottom prevents it from absorbing too much water in the rain or transpirating too much in the sun.