Leptotene Stage of Meiosis in Plants
Leptotene is the stage of meiosis in which the chromosomes are threadlike in shape. At the leptotene stage the chromosomes become visible as long, thin threads. At pachytene they pair, the corresponding portions of the two chromosomes lying side by side. The chromosomes then duplicate and contract. During this stage, the chromosomes join themselves by their ends to the inner membrane of the nuclear envelope. At the transition to the zygotene stage the telomeres usually aggregate at a nuclear envelope sector, thereby forming a meiotic bouquet.Lateral (axial) elements of the synaptonemal complex are also formed.
The changes of this sub-phase are as follows;
(i) Dehydration of nucleus is started
(ii) As a result of dehydration, the chromosomes start becoming short and thick (due to coiling) and have pigment bearing capacity
(iii) Numerous chromomeres are found in the chromosomes.
(iv) Dehydration and chromosome coiling go on continuously.