Question

Stomata can also open at night present in
(a) Xerophytes
(b) Gametophytes
(c) Hydrophytes
(d) None of the above

Answer 1

Hint: Stomata regulates water movement in plants. If a plant is opening its stomata at night that means it must be present in areas having water scarcity, so that the loss of water can be recovered.

Complete answer:
Plants living in extreme habitats of desert such as xerophytes have special adaptations to cope with long spells of hot, dry weather. Xerophytes have abundant storage capacity for water collected during the short rainy season. At the same time they keep their stomata closed during the day time to cut down on transpirational loss and also reduce surface area by replacing leaves with thorns. They open their stomata at night when it is more humid and the air temperature is cooler to absorb carbon dioxide from the atmosphere. Gametophyte is not a plant but a phase during the life cycle of certain plants. Gametophyte is the gamete-producing and usually haploid phase, producing the zygote resulting in the sporophyte. Hydrophytes are plants that grow wholly or partly submerged in water. They keep their stomata open most of the time due to water abundance.

Additional information :
Xerophytes are plant species that have evolved to survive in dry areas such as desert. They have the following adaptations for better survival:
1. They have thick cuticles.
2. The stomata are closed during the day.
3. Reduction in number of stomata.
4. Stomata hidden in crypts or depressions in leaf surfaces (less exposure to wind and sun).
5. Increased water storage.
6. Thicker leaves and stems, or leaves reduced in number, or leaves drop off during the dry season.
7. These plants have deep taproots or wide spreading fibrous roots near the soil surface.
8. They show reduction in $H_2O$ loss from wind by adapting to low growth forms.
9. They have reduced life cycles.

So, the correct answer is, ‘Xerophytes’.

Note: Xerophytes exhibit CAM (Crassulacean acid metabolism) photosynthesis as a response to arid conditions. Stomata in a plant using CAM remain shut during the day to reduce evapotranspiration, but open at night to collect carbon dioxide.