Question

Angiospermic plant has a chromosome number of 12. What will be the chromosome number in integuments and nucellus?  
A. 4         
B. 6   
C. 12                    
D. 24

Answer 1

Hint: The sporophyte comprises the nucellus, mother cells for microspores, and mother cells for megaspores, and has either one or two complete sets of chromosomes, depending on its haploid or diploid makeup, depending on the ploidy.


Step by step solution:
It has been told in the question that the chromosome of the flowering plant is 12 so we need to find the chromosome number of different parts of the plant. Since we know that in angiosperms development is from sporophyte which is of diploid ploidy.
Integuments- The evolutionary origin of the inner integument, which is crucial for the formation of ovules from megasporangia that occur inside the nucellus of developing ovules in angiosperms, has been hypothesised to be the enclosure of a megasporangium by sterile branches. Chalaza is the origin of both the integuments and the basal swelling section of the nucellus. The integuments have a diploid ploidy. Therefore, the answer to the query will be that the integument has 12 chromosomes.
Nucellus- Being a parent cell once more, the megaspore mother cell will undergo meiosis to produce 4 haploid megaspores, therefore their ploidy is 2n. The core of the ovule, which contains the embryo sac, is called the nucellus, and it is diploid. Consequently, there will be 12 chromosomes.
Hence, the correct option is C. 12

Note: The sporophyte is the diploid multicellular stage of a plant or alga's life cycle. Each sporophyte cell has a double pair of chromosomes and is created by the zygote created when a haploid egg cell is fertilised by a haploid sperm.