Tag: morphology of leaf

In grasses and many monocots, the leaf base (petiole) is broad and surrounds the stem as an envelope. Such a leaf base is known as sheathing leaf base. In grasses such as wheat, maize and grass, the sheathing leaf base protects the intercalary meristem. Hence, the plants belonging to family Poaceae have sheathing leaf base.

• Minerals crystals are found in plant cell walls in the form of calcium oxalate, carbonate or silica.
  
• Silicon is found on the leaf surface in the form of spines and other sharp bodies which are known as phytoliths.
  
• It makes the grasses abrasive and foliage indigestible to organisms feeding on them (herbivores).
• Silica incrustation is the deposition of silicon on the leaf surface, it is a defence mechanism found in closely related species of grasses which makes its leaves abrasive.
• So, the correct answer is 'Grasses'.

• Plastochron is the time interval between the two successive events during the growth of plants.
  
• As in the case, when the shoot tip of a plant grows new leaves are produced at regular time intervals.
• This time interval between the beginning of leaf growth at 2 consecutive nodes in a growing shoot apex by keeping the temperature constant is called Plastochron.
• So, the correct answer is 'Period between two successive leaf primordia'

Veins have vascular tissues xylem and phloem. Xylem fulfills the requirement of water of the leaves. Phloem transport food energy to the leaves. They also provide support for the leaf.

• Minerals crystals are found in plant cell walls in the form of calcium oxalate, carbonate or silica.
  
• Cystoliths refers to the deposition of calcium carbonate in the epidermal cells of leaves of the plants belonging to the genus Acanthaceae and Urticaceae (stinging nettles).
• So, the correct answer is 'Cystoliths'.

• A leaf base is also known as hyphopodium, it is the lowermost part of the leaf which is slightly expanded region where the leaf get attached to the stem.
  
• It is indistinct in most of the plants which act as a cushion for the leaves.
• The vegetative shoot apex consists of two regions i.e, summit and flank.

1. Summit-  The rate of division is slow and it is located at the apex.
   
2. Flank- The rate of division is very fast and it lies behind the summit.
   

• Leaf primordium is formed on the flanks by the flank meristem.
  
• So, the correct answer is 'Leaf base'

In an unifacial leaf, the stomata are present in lower and upper epidermis. Unifacial leaf is also called as isobilateral or amphistomatic. Unifacial leaf is a leaf that develops from one side of the leaf primordium only and in consequence has only an encircling adaxial or abaxial epidermis (may be secondarily flattened and appear dorsiventral).
Thus, the correct answer is option C.