Table 1.

Histological modifications associated with seed shattering in different plant species.

Species	Histological Modification	Observed Phenotype	Reference
A. thaliana	Lignification of the valve margin cells	Increase of the mechanical tension at the valve margin in the dry silique, and seed shattering	Liljegren et al. [5] Liljegren et al. [8]
A. thaliana	Presence of a functional abscission layer (i.e., separation layer) between valves and replum	Separation of the valves from the replum in the dry silique, and seed shattering	Rajani and Sundaresan [6]
C. hirsuta	Asymmetric lignin deposition in the endocarp b cell walls (internal valve layer)	Explosive seed shattering and valve curling	Hofhuis et al. [25]
H. spontaneum; H. vulgare	Reduced cell-wall thickness of cells of the separation layer/Cell wall thickening of cells of the separation layer	Brittle-rachis (disarticulation of the spikelet from the rachis)/Non-brittle rachis	Pourkheirandish et al. [14]
O. nivara; O. sativa	Presence of a continuous abscission cell layer at the junction between the pedicel and the flower/discontinuous or absent separation layer	Detachment of the grain from the pedicel and easy threshing of the panicle/reduction or loss of seed shattering	Konishi et al. [10] Li et al. [11] Zhou et al. [12] Yoon et al. [13]
G.max	Secondary cell-wall thickening in the fiber cap cells of the ventral suture (dehiscence zone)	Resistance to pod shattering	Dong et al. [16]
G. soja; G. max	Presence of an internal lignified valve layer	Increase of pod shattering	Funatsuki et al. [15]
P. vulgaris	Strong lignin deposition in the cells that surround the dehiscence zone	Increase of pod shattering	Murgia et al. [27]
P. vulgaris	Presence of an internal lignified valve layer	Increase of pod shattering	Murgia et al. [27]