Figure 1.

Morphological and cytological features of J4B and J4A cotton anthers. Morphology of the filament morphology of J4B (A) and J4A (E). SEM images of the frontal view of mature pollen grains in anthers of J4B (B1) and J4A (F1); SEM images of the lateral view of mature pollen grains in anthers of J4B (B2) and J4A (F2). TEM images of J4B and J4A anthers at the pollen mother cell stage (C1,C2,G1,G2), the tetrad stage (D1,D2,H1,H2), and the mature pollen grain stage (J1,J2,P1,P2). I₂-KI staining of J4B and J4A pollen grains (I,O). Semi-thin sections of J4B and J4A anthers during the pollen mother cell stage (K,Q), between the pollen mother cell stage and meiosis stage (L,R), at the meiosis stage (M,S), and at the tetrad stage (N,T). Ep, exodermis; En, endoderm; ML, middle-level; T, tapetum; N, nucleus; PMC, pollen mother cell; M, mitochondrion; Te, tetrad; P, pollen. Scale bars of (A) and (E) correspond to 1 cm; scale bars of (B1,D2,F1,H2) correspond to 100 μm; scale bars of (B2,F2,N,R,T) correspond to 20 μm; scale bars of (C1,C2,D1,G1) correspond to 5 μm; scale bars of (G2,I,O) correspond to 50 nm; scale bars of (H1,J1,J2,K–M,P1,P2,Q,S) correspond to 10 μm.