Question

Aggregate fruit develops from
A. Syncarpous ovary
B. Multicarpellary, syncarpous ovary
C. Unilocular ovary
D. Multicarpellary, apocarpous ovary

Answer 1

Hint: An important characteristic of angiosperms is the formation of fruit . Gynoecium containing more than one carpel and which are free from each other can form a single fruit and the fruit is the fertilized ovary.

Step by step answer:Angiosperms are the flowering plants in which flowers act as reproductive units. A flower has four different kinds of whorls arranged successively on the thalamus or receptacle which is a swollen end of the stalk.
Calyx, corolla, androecium, and gynoecium are the four different whorls where calyx and corolla are accessory organs while androecium and gynoecium are reproductive organs. Calyx protects the flower in the bud stage. The calyx is the outermost whorl of the flower whose members are leaf-like sepals. If the sepals are united then that condition is called as gamosepalous and if they are free then that condition is called as polysepalous. Corolla consists of petals which are brightly coloured to attract insects for pollination. when petals are united that condition is called gamopetalous and if the petals are free then that condition is called polypetalous.
Stamen represents the male reproductive organ and androecium is composed of the stamen. Each stamen is composed of a stalk also called filament and anther. If stamens are united into one bunch then it is called monadelphous, and if stamens are united into many bundles then it is called polyadelphous.
The female reproductive part of the flower is gynoecium. The gynoecium is composed of pistils. If the gynoecium consists of a single pistil then it is a monocarpellary condition and if more than one pistil then it is a multicarpellary condition.
In a multicarpellary condition, if pistils are fused together then it is called syncarpous and if the pistils are free then it is called apocarpous. Syncarpous condition is found in Papaver and the apocarpous condition is found in Michelia.

Double fertilization is a characteristic feature of angiosperms only. In double fertilization syngamy and triple fusion takes place to form a diploid zygote and a triploid endosperm respectively. The zygote develops into an embryo and the embryo derives its nourishment from the endosperm. The embryo may be monocot or dicot depending upon the number of cotyledons present in it. The final product of sexual reproduction is the seed. At the end of sexual reproduction ovary develops into fruit and ovules develop into seed. The fruits are classified into three categories that are simple fruits, aggregate fruits, and composite fruits.
Aggregate fruit is a collection of simple fruitlets that develops from multicarpellary apocarpous ovaries. aggregate fruit is also called etaerio. Examples: etaerio of achenes (Strawberry), etaerio berries (Custard apple), etaerio of follicles (Calotropis).
Hence option D is correct.

Note: Not all fruits are the products of sexual reproduction, for example, parthenocarpic fruits are the ones that develop without fertilization. Similarly, not all ovaries develop into fruits, for example, in apples and cashew the fruits develop from the thalamus. Such fruits are false fruits.