Question

110
type of embryo sac is characterized by the absence of synergids and
antipodals.
a) Plumbago
b) Allium
c) Endymion
d) Adoxa​

Answer 1

Answer:

ANSWER

In bisporic embryo sacs, meiosis produces only two megaspores, each containing two haploid nuclei, due to the absence of cytokinesis and cell plate formation following the second meiotic division. The megaspore nearest the micropyle then undergoes programmed cell death, leaving a single functional megaspore with two haploid nuclei. It is also known as Allium type embryo sac.

In the monosporic, or Polygonum-type embryo sac, meiosis of the diploid megaspore mother cell in the nucellus produces four haploid megaspores. Three of the megaspores, usually those at the micropylar end of the nucellus, subsequently undergo programmed cell death, leaving only one functional megaspore.

In tetrasporic embryo sacs, cell plates fail to form after both meiotic divisions, resulting in a single four-nucleate megaspore. All three patterns give rise to a single functional megaspore that contains either one (monosporic), two (bisporic), or four (tetrasporic) haploid nuclei.

Thus, the correct answer is option B.