No abstract

SummaryThe structure of the surfaCe wax on green and glaucous variants in Eucalyptus urnigera, Poa colensoi (natural cline forms), Pisum sativum, and BraBsica oleracea (mutants) are described as seen under the electron microscope. Preliminary chemical data are also given. The green forms always possess wax deposits which are either smooth films on the cuticle or consist predominantly of platelets which lie flat on the cuticular surface. In some cases the platelets tend to be arranged in parallel groups. In the glaucous variants, the wax consists predominantly of rods or filaments growing outwards from the leaf surface and presenting many light-scattering surfaces.Chemical data show a higher ,B-diketone content with wax from glaucous plants in both Eucalyptus and Poa. Glaucous BraBsica has a higher ketone content.

No abstract

No abstract

SummaryExtracuticular wax and contact angles on wheat were studied because of their influence on the retention of chemical sprays and on disease resistance. Wax formed extensive deposits on wheat, irrespective of variety, stage of growth, or part of the plant, and these deposits overlaid or projected from the cuticle as platelets and rodlets. Platelets covered the adaxial and abaxial leaf surfaces of seedlings and some mature plants, while a net of rodlets covered the ear, culm, sheath, and flag leaf abaxial surface. Rods were occasionally present on the abaxial surface of mature vegetative leaves. Wax influenced the advancing contact angle of water droplets on wheat. Contact angles were all high, i.e. greater than 130° and generally about 150°. The contact angle on the adaxial leaf surface was higher than on the abaxial leaf surface, except on glasshouse-grown reproductive plants, where there was no difference between the two sides. Seedlings had higher contact angles than mature plants, but there was no trend in contact angle with tissue age within a leaf or within a mature plant. The contact angle on the flag leaf of glasshouse-grown reproductive Aotea plants was 24° higher than on a similar plant grown in the field.