Results: 5

1.
Fig. 5.

Fig. 5. From: CELL WALL INVERTASE 4 is required for nectar production in Arabidopsis.

cwinv4 flowers accumulate decreased total soluble sugar. Whole flowers (Stage 14–15) from both cwinv4-1 and cwinv4-2 displayed significantly lower levels of total soluble sugar (sucrose and glucose) than wild-type plants (n=3, *P=0.027 and 0.013, respectively). Results are displayed as total absorbance per mg of floral tissue ×100. The relative proportion of sucrose-to-glucose was similar between cwinv4 and wild-type flowers (data not shown).

Jeffrey M. Ruhlmann, et al. J Exp Bot. 2010 January;61(2):395-404.
2.
Fig. 2.

Fig. 2. From: CELL WALL INVERTASE 4 is required for nectar production in Arabidopsis.

Identification of cwinv4 mutants. Two independent Arabidopsis T-DNA mutant lines (Alonso et al., 2003), cwinv4-1 (SALK_130163) and cwinv4-2 (SALK_017466C), were obtained from the Arabidopsis Biological Resource Centre and genotyped to obtain homozygous mutant plants. The relative locations of each T-DNA insertion are shown in (A). RT-PCR, performed on RNA isolated from whole flowers, demonstrated that cwinv4-1 is a null mutant, and that AtCWINV4 is expressed significantly lower in cwinv4-2 flowers than in wild-type (B).

Jeffrey M. Ruhlmann, et al. J Exp Bot. 2010 January;61(2):395-404.
3.
Fig. 3.

Fig. 3. From: CELL WALL INVERTASE 4 is required for nectar production in Arabidopsis.

Cell wall invertase activity is greatly reduced in cwinv4 flowers. Cell wall extracts were prepared from whole Stage 14–15 flowers (25 mg fresh weight) of wild-type and cwinv4 plants, which were subsequently tested for invertase activity. The results from one experiment with cwinv4-1 and cwinv4-2 plants are shown (n=3 independent preparations). Independent and repeated experiments with both cwinv4-1 and cwinv4-2 plants displayed consistent results, with varying amplitudes of total activity for both wild-type and mutant plants.

Jeffrey M. Ruhlmann, et al. J Exp Bot. 2010 January;61(2):395-404.
4.
Fig. 4.

Fig. 4. From: CELL WALL INVERTASE 4 is required for nectar production in Arabidopsis.

cwinv4 flowers do not secrete nectar. Nectar production in Arabidopsis flowers can be examined by gently peeling back the sepal. Nectar droplets accumulating within the sepal cups surrounding lateral nectaries (LN) were consistently present in wild-type plants (circled in A), whereas neither cwinv4 mutant secreted nectar (e.g. B; Table 2). Both cwinv4 mutants also accumulated higher than normal levels of starch within the receptacle (arrowheads), which often extended into the pedicel (C, D). Conversely, the stomata of wild-type nectaries stained heavily for starch (E, arrowheads), whereas those of cwinv4 flowers did not (F). The morphology of cwinv4 nectaries was examined to determine if aberrant nectary structure might account for the lack of nectar secretion. In all flowers examined, cwinv4 nectaries (H) appeared to have similar morphology to wild-type plants (G). Scale bars are 50 μm; LN, lateral nectary; SS, short stamen.

Jeffrey M. Ruhlmann, et al. J Exp Bot. 2010 January;61(2):395-404.
5.
Fig. 1.

Fig. 1. From: CELL WALL INVERTASE 4 is required for nectar production in Arabidopsis.

CWINV4 is highly expressed in nectaries. Reverse transcription-polymerase chain reaction (RT-PCR) was used to examine the expression profiles of AtCWINV4 (A) and an orthologue from Brassica rapa (B; BrCWINV4, accession number GQ146458). The tissues examined in (A) included: (1) petal; (2) sepal; (3) rosette leaf; (4) stamen; (5) pistil; (6) root; (7) internode shoot; (8) silique; (9) mature median nectaries (Stage 14–15); (10) immature lateral nectaries (Stage 11–12); and, (11) mature lateral nectaries (Stage 14–15). (B) Tissues included: (1) petal; (2) sepal; (3) leaf; (4) stamen; (5) pistil; (6) root; (7) stem; (8) mature median nectaries; and (9) mature lateral nectaries. GAPDH (At3g04120) and a B. rapa ubiquitin gene (BrUBQ, accession number GR719937) were used as constitutively expressed controls. All B. rapa floral tissues examined were from the equivalent of Stage 14–15 Arabidopsis flowers. The images shown are the results obtained after 27 cycles of RT-PCR. (C) Bright field image of Stage 15 Arabidopsis flower expressing an AtCWINV4:GFP fusion, under control of the native AtCWINV4 promoter, and (D) GFP fluorescence derived from same flower. Sepals were removed prior to imaging. Re, receptacle; Pe, petal; LS, long stamen; MN, median nectary; LN, lateral nectary; scale bars, 100 μm.

Jeffrey M. Ruhlmann, et al. J Exp Bot. 2010 January;61(2):395-404.

Supplemental Content

Recent activity

Your browsing activity is empty.

Activity recording is turned off.

Turn recording back on

See more...
Write to the Help Desk