XI 



PLATES 



Fig. 1. Oat seedling affected with grey speck facing page 60 



Fig. 2. Oat leaf exhibiting the characteristic symptoms 



of grey speck 60 



Fig. 3. Sugar beet suffering from manganese deficiency 60 



Fig. 4. Peas suffering from marsh spot 61 



Fig. 5. Sugar beet suffering from boron deficiency 84 



Fig. 6. Mangold suffering from boron deficiency 84 



Fig. 7. Transverse section through swedes showing 



characteristic appearance of brown heart 85 



Fig. 8. Longitudinal section through swede affected with 



brown heart 85 



Fig. 9. Late stage in boron-deficient swede 86 



Fig. 10. Boron-deficient cauliflower 86 



Fig. 1 1 . Stem of cauliflower suffering from boron de- 

 ficiency and showing very typical breakdown of 

 central tissue 87 



Fig. 12. Effect of concentration of copper on the growth 



of oats 9 2 



