spacer gif spacer gif spacer gif spacer gif spacer gif
QUICK SEARCH:   [advanced]


spacer gif
     Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents    

doi: 10.1242/10.1242/dev.00243

This Article
Right arrow Summary Freely available
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Scarpella, E.
Right arrow Articles by Meijer, A. H.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Scarpella, E.
Right arrow Articles by Meijer, A. H.

The RADICLELESS1 gene is required for vascular pattern formation in rice

Enrico Scarpella*, Saskia Rueb and Annemarie H. Meijer{dagger}

Institute of Molecular Plant Sciences, Leiden University, Clusius Laboratory, PO Box 9505, 2300 RA Leiden, The Netherlands
* Present address: Department of Botany, University of Toronto, 25 Willcocks Street, Toronto ON, M5S 3B2, Canada



View larger version (115K):

[in a new window]
  		Fig. 1. Anatomy of wild-type and ral1 mature embryos and plants. (A-E,K,M-P,U,W) Wild type. (F-J,L,Q-T,V,X) ral1. (A-C,F-H) Longitudinal sections through a mature embryo showing details of the embryonic axis (A,F), the shoot apical region (B,G) and the basal region of the scutellum (C,H). Note that the absence of vasculature in F and G, as compared with A and B, is due to the fact that in ral1 the plumule lies slightly off the median plane. (D,I) Detail of the dorsal region of the scutellum in a transverse section through a mature embryo 180 µm below the scutellum tip. (E,J) Schematic representation of a median longitudinal section through a mature embryo (left) and of a dorsal view of a mature embryo (right). The embryonic provascular system is shown in green. (K,L) Region between two large veins in a transverse section through the middle of a mature leaf blade. (M,Q) Midrib region in a transverse section through the middle of a mature leaf blade. Arrows in M indicate the veins of the wild type that are missing in ral1. (N,R) Detail of the upper right-hand corner in M and Q, respectively. (O,S) Detail of the large vascular bundle of the midrib in M and Q, respectively. (P,T) Detail of transverse sections through the apical region of the first internode showing details of the internode wall. (U,V) Transverse section through an adventitious root 12 mm from the root tip. (W,X) Detail of the vascular cylinder in U and V, respectively. Toluidine Blue-stained granules in F,G,I showed typical blue-brown staining with iodine solution (not shown), revealing ectopic starch formation. bs, bundle sheath extension; lv, large vein; mp, metaphloem; mx, late metaxylem element; p, plumule; r, radicle; s, scutellum; sc, sclerenchyma; sv, small vein; v, provascular tissue. Scale bars: (A,F) 150 µm (B,D,G,I,K,L,N,O,R,S) 50 µm (C,H,M,Q,P,T,U,V) 100 µm (W,X) 25 µm.

 


View larger version (50K):

[in a new window]
  		Fig. 2. Morphology of wild-type and ral1 seedlings and mature plants. (A-F) Wild type. (G-L) ral1. (A,G) 3-day-old seedling. (B,H) 6-day-old seedling. (C,I) Root system of a 3-week-old seedling. (D,J) 6-month-old plant. (E,K) Mature spikelet. (F,L) Floral organs in a bisected spikelet. a, adventitious root; l, lemma; p, palea; r, radicle (seminal root). Corresponding ral1 and wild-type images are at the same magnification.

 


View larger version (108K):

[in a new window]
  		Fig. 3. Morphology and anatomy of wild-type and ral1 leaf blade commissural veins. (A,M,N) Wild type. (B-L,O,P) ral1. (A-L) Dark-field images of cleared leaves. (A) Uninterrupted commissural vein connecting two longitudinal veins. (B,C) Interrupted simple (B) or compound (C) commissural vein associated with one longitudinal vein. (D,E) Interrupted simple (D) or compound (E) commissural vein associated with two longitudinal veins. (F) Uninterrupted `Y' vein forming two connections with one longitudinal vein and one with the other. (G-K) Y veins showing interruptions at different positions. (L) Isolated patch of xylem elements (vascular island). (M-P) Paradermal sections through mature leaf blades. (M) Uninterrupted commissural vein connecting two longitudinal veins. (N) Detail of M. (O) Interrupted simple commissural vein associated with two longitudinal veins. (P) Detail of O. Scale bars: (A-L) 50 µm (M-P) 25 µm.

 


View larger version (158K):

[in a new window]
  		Fig. 4. Vascular development in wild type and ral1. (A-C,G,I,K,O-R,W,Y) Wild type. (D-F,H,J,L-N,S-V,X,Z) ral1. (A-F) Transverse sections through 2-week-old seedlings, 10 µm above the insertion of the first (A,D), second (B,E) and third (C,F) leaf primordium on the shoot apex (sixth, fifth and fourth leaf, respectively). (G-J) DR5-GUS (G,H) or Oshox1-GUS (I,J) expression in transverse vibratome sections (100 µm) through the shoot apex of 2-week-old seedlings. (K-N) Transverse section 200 µm above the shoot apex of 2-week-old seedlings showing Oshox1-GUS expression that identifies commissural veins developing in the fourth leaf primordium (third leaf). (O-V) DR5-GUS (O,P,S,T) or Oshox1-GUS (Q,R,U,V) expression in vascular bundles at a comparable stage of differentiation in the fourth (second protoxylem element stage; O,S,Q,U) and fifth (late metaxylem element stage; P,T,R,V) leaf primordium (third and second leaf, respectively). Xylem is oriented to the right. (W,X) Oshox1-GUS expression in mature embryos (dorsal view). (Y,Z) Schematic representation of the dorsal view of mature embryos showing the vascular system of the scutellum expressing (in blue) or not (in black) Oshox1-GUS. 1, 2, 3, first, second, and third leaf primordium, respectively; pp, protophloem; pv, provascular strand; px, protoxylem. Scale bars: (A-F) 100 µm (G-N) 50 µm (O-V) 25 µm (W,X) 350 µm.

 


View larger version (80K):

[in a new window]
  		Fig. 5. Hormonal responses of wild type and ral1. (A,C,E-H,M-P,Q,S,U) Wild type. (B,D,I-L,R,T,V) ral1. (A-D) Seedlings 1 week (A,B) or 3 weeks (C,D) after callus induction on 2 mg/l 2,4-D. (E,F,I,J,M,N) Calli at the stage of transfer to the induction medium (E,I,M) and 3 weeks after (F,J,N) the transfer. Medium contained either 2 mg/l 2,4-D (E,F,I,J) or 1 mg/l 2,4-D (M,N). (G,H,K,L,O,P) Sections through the calli in F (G,H), in J (K,L), or in N (O,P). (Q-V) DR5-GUS expression in the root of 1-week-old seedlings grown for 24 hours on filter paper moistened with water (Q,R), with 0.1 (S,T) or 1 (U,V) µM NAA. (W,X) Frequency of shoot (W) or root (X) regeneration via somatic organogenesis in callus tissues grown on hormone-free medium (black diamond, wild type; black triangle, ral1) or on medium supplemented with cytokinin (black square, wild type; cross, ral1). The results represent the mean±s.e.m. of two separate experiments each performed on a population of 80-100 calli per genotype and per treatment. Difference between wild-type and ral1 populations as determined by repeated-measures analysis of variance (single-factor ANOVA) was significant (P<0.001) at all time points. (Y) Relative elongation over 24 hours of wild-type seminal (white boxes) and adventitious (grey boxes) roots and ral1 (black boxes) roots in the presence of 0.05 µM 2,4-D or 0.1 µM NAA. The results represent the mean±s.e.m. of two separate experiments each performed on a population of 20-35 seedlings per genotype and per treatment. Asterisks indicate the significance of difference between wild-type and ral1 populations as determined by repeated-measures analysis of variance (single-factor ANOVA). *0.01<=P<0.05, **0.001<=P<0.01. b, shoot base; pe, proembryonic structure; s, scutellum. Scale bars: (A-D,E,F,I,J,M,N) 2 mm (G,K) 100 µm (H,L,O,P) 25 µm (Q-V) 50 µm.

 




© The Company of Biologists Ltd 2003