io8 MICROSCOPICAL RESEARCH 



PLATE XIX. 



CELL STRUCTURE AND CELL CONTENTS. 



Fig. 66. Longitudinal median section through Apex of Embryo of 

 Wheat aiter twenty-four hours' germination in ' milk-warm ' 

 water. Cut ^/looo in- x 80 dia. Fixed with Corrosive-Picro- 

 Formaldehyde solution. Stained with Brazilin. 1. Axis of 

 embryo.2. Growing point of stem. 3 — 4. Leaves in various 

 stages of development. 



Fig. 67. Longitudinal median section through radical end of 

 Embryo of Wheat, after twenty-four hours' germination in 

 'milk-warm' water. Cut ^/looo in. x 80 dia. Fixed and 

 stained as above. 1. Central axis of developing root. 



2. Apex of root. 3. Protective root-cap. 4. Root-sheath. 

 5. Cells to form Epidermis (dermatogen). 6. Cells to form 

 cortical tissue (periblem). 7. Cells to form the vascular 

 system or root (plerom). 



Fig. 68. Longitudinal section through Embryo of Wheat (before 

 fertilisation) x 35 dia. Fixed with Chromo-Acetic solution. 

 Stained with Brazilin. 1. Spongy tissue of ovary. 2. Ovule. 



3. Young embryo. 



Fig. 69. Longitudinal section through Embryo of Wheat (after 

 fertilisation). Prepared as above. 1. Spongy tissue of 

 ovary. 2. Embryo. 3. Disposition of cells to form seed 

 coat. 



