Heterocysts in Anabaena is helpful in

• secondary growth

• nitrogen-fixation

• ion uptake

• gaseous exchange

The statement given below are the deficiency symptoms of a certain element. Identify the element with the help of options that follow.

I. Stunted growth

II. Tissue necrosis

III. Curling appear first in young leaves

IV. Premature flower abscission

Choose the correct option

• magnesium

• boron

• calcium

• nitrogen

The nitrifying bacteria that convert the ammonia to nitrates are

• Nitrosomonas and Nitrobacter

• Azotobacter

• Rhizobium sp.

• Thiobacillus denitrificans

Insectivorous plant is

• Cuscuta

• Drosera

• Striga

• None of the above

Nodules with nitrogen-fixing bacteria are found in

• cotton

• gram

• mustard

• wheat

Mycorrhiza is an example of

• endoparasitism

• decomposers

• symbiotic relationship

• ectoparasitism

A metal ion involved in stomatal regulation is :

• iron

• potassium

• zinc

• magnesium

The plant ash is an indication of :

• organic matter of plant

• waste product

• mineral salts absorbed by plants

• none of these

Hydroponics is

• cultivation of plants in water

• growth of plants towards water

• growth of plants away from water

• soil less cultivation of plants

When one element is involved in opening and closing of stomata, the other helps to maintain the ribosome  structure. They are

• Potassium and calcium

• Phosphorus and sulphur

• Potassium and magnesium

• Iron and magnesium

• Iron and magnesium