Choose between the two options to answer the question specified in the brackets for the following: Example: Corolla or Calyx (Which is the outer whorl?) Answer: Calyx
Lenticels or stomata (Which one remains open always?)
Topic: Lenticels
Answer
LENTICELS.
LENTICELS are permanently open pores in the bark of woody stems. They have no mechanism for closing.
STOMATA can OPEN AND CLOSE, controlled by the GUARD CELLS — which is exactly what makes them different. When the guard cells are turgid the pore opens; when flaccid it closes.
WHY THE PLANT NEEDS BOTH: the stomata must be closable, since they are the route of most water loss and the plant must be able to shut them in drought or at night. The lenticels lose very little water and exist chiefly so that the living cells beneath a thick corky bark can still exchange gases.
HYDATHODES are also permanently open, and give out liquid water in guttation.