Question

Anthesis is a phenomenon which refers to
A. Reception of pollen by stigma
B. Formation of pollen
C. Development of anther
D. Opening of flower bud

Answer 1

Anthesis is a flowering period. It includes a style of extension, maturation of stamen and finally colour change. In this, the flowers typically attract nocturnal insects including more number of moth species.

Complete answer:
Anthesis is a period during which the flower is open and also it becomes more functional. It is also referred to as the onset of that particular period. So this anthesis is spectacular in some species. For example, for the species Banksia, anthesis involves the propagation of style far beyond the perianth. The contrast of interest is constant throughout the inflorescence. So, if the perianth and style are of different colours, then a pronounced discolouration will appear, which gradually spreads along the inflorescence.
This anthesis involves in the process of extension of the style far from the upper parts. It is a phenomenon that is referred to a formation of the pollen and then the development of anther and the opening of the flower bud then finally reception of pollen by the stigma.
Flowers with diurnal anthesis are generally brightly coloured to attract insects, such as butterflies. Flowers with nocturnal anthesis are generally white or less colourful and also such as, they contrast more heavily in the night. These flowers typically attract nocturnal insects, they are including many numbers of moth species. It is the duration of the life of a flower from the opening of the bud to the setting of the fruit.

Hence, the correct answer is option (D).

Note: The time in which the flowering plant seems to be a response to a combination of factors including like day, temperature, and also rainfall, but it may also be initiated by the addition of gibberellins, is one of the group of growth-promoting substances. It is a reproductive part of angiosperms.