PMC

Petal breakstrength meter overview. (A) The petal breakstrength meter consists of a petal gripper, a sensor, electronic circuit and personal computer. (B) Close up of sensor showing 5 cm aluminum bar attached to sensor cantilever. Petal gripper is attached to the distal end of lever with a piece of braided wire. (C-E) Petal gripper (SMD grabber with 1 mm pieces of 20 gauge insulation glued to tips) in use. (C) Petal gripper is opened. (D) Grabbing onto a flower petal that is still attached to flower. (E) After pulling on the inflorescence, petal detaches from receptacle and remains in the jaws of petal gripper. (F) Assembled electronic circuit housed in an ABS plastic enclosure (lid removed).

Distribution of epidermal types along a proximo-distal axis within the same petal. (A–E) Lupinus littoralis with transitions from poorly differentiated cells at the base of the adaxial side in the dorsal petal (C), to papillose cells (PCS) on the central part and apex of the petal (A, B). (F–J) the abaxial side of the dorsal petal in Lotus japonicus with transitions from poorly differentiated cells at the base of the petal (H) to PCS in the central and distal regions (G, H). A photograph of the standard petal of Lotus japonicus is shown besides the images with the claw separated and shown below. (K–P) The adaxial side of the dorsal petal in Lathyrus sylvestris has a transition zone from TRS to PLS on the borders of the petal where cells have a mixture of morphological features of both epidermal types. (Q–V) The abaxial side of the lateral petal in Lotus japonicus where TRS is mainly observed at the base and in the central part of the petal, and there is a transition zone from TRS to PCS where the cells have a mixture of both epidermal types. Scale bars: (A, C, F, J–M) = 100 µm; (B) = 500 µm; (D, H, I, O–S) = 50 µm; (G) = 200 µm; (E, N, T–V) = 20 µm.

Phenotypes of BEH-VIGS; petal spurs are short, twisted or bent. (A) A mature, wildtype A. coerulea flower. (B) A mature, ANS control flower, with three phenotypically normal white petals. (c) Mature BEH-VIGS flower with petals with bends in the lower part of spur and a spur with a 90° bend and abaxial outgrowth (arrowheads). (D) Mature BEH-VIGS flower with three short petal spurs (arrowhead), and one phenotypically normal petal spur (asterisk). (E) Mature BEH-VIGS flower with petal spurs with a twisted petal and abaxial outgrowths (arrowheads), compared with two phenotypically normal spurs (asterisk). (F) Mature BEH-VIGS flower showing phenotypically normal sepals and petal blades (asterisks), compared with small sepals and petal blades (arrowheads). (G) Young BEH-VIGS flower with petal spurs with abaxial outgrowths and 90° bends in the lower spur (arrowheads), compared with two phenotypically normal petal spurs (asterisks). (H) SEM of ANS control lower spur showing anisotropically elongated cell and parallel files of cells in the lower spur. (I) SEM of BEH-VIGS lower spurs showing short, misaligned cells. (J) Comparison of WT, ANS control and BEH-VIGS petals (p). Arrows indicate if a BEH-VIGS petal showed decreased (down) or increased (up) relative expression of AqBEH genes (see ). (K) Measurements of petal spur lengths in control (n = 14, mean 4·42 cm) and BEH-VIGS (n = 21, mean 3·14 cm) petals. Welch t-test, P < 0·0001. (L) Cell lengths of ANS control (mean 94·2 μm) and BEH-VIGS petal spurs (mean 55·5 μm). Welch t-test, P < 0·0001. (M) Cell anisotropy of ANS control (mean 4·1) and BEH-VIGS petals spurs (mean 2·3). Welch t-test, P < 0·0001. Scale bars: (A–G, J) = 1 cm; (H–I) = 50 μm.

Flower development in the wild-type (A,D–F) and lel plants (B,C,G–L) of C. bursa-pastoris (SEM). (A–C) Inflorescence apices with flowers at the sequential stages of early development. The flowers are numbered sequentially from the youngest to the oldest. (D–F) The earliest stages of petal development in the wild type. (D,E) A flower with lateral sepals removed. (D) Top view. (E) Detail of side view. It is noted that the very small petal and the virtual absence of stamen filaments. (F) A flower with sepals removed. The petal is larger than in (E), and very short stamen filaments are present. (G–L) Early petal development in lel plants. (G) Side view of a flower with one median sepal removed. It is noted that the gaps on either side of the visible pair of long stamens. A small petal primordium is present in the right-hand gap. (H) A flower with a sepal and a stamen removed. (I) Detail of (H) showing a petal primordium. (J) Side view of a flower with three of four sepals removed. A young petal is present left to the removed median sepal. There is no petal right to the median sepal (although there is enough space for its initiation). (K) Detail of (J) showing the petal. (L) Side view of flower with a median sepal partially removed. There is a petal right to the median sepal, but no petal left to it. g, gynoecium; ia, inflorescence apex; ls, lateral sepal; lst, long stamens; ms, median sepal; p, petal; sst, short stamens; wt, wild type. Scale bars: 30 μm.