Question

what are the matorial's requlirad
to obsexie spores in fem leaf.​

Answer 1

Answer:

The release of diffusible substances from plant leaves, fungal spores or from pollen into water droplets on the surface of leaves is discussed in relation to (1) direct and indirect effects on spores of pathogens and (2) the effect on the growth of saprophytic micro‐organisms. Evidence suggests that competition for nutrients in droplets on leaves may limit germination of spores of some pathogens. Modification of the chemical environment of leaf surfaces by saprophytic micro‐organisms is discussed in relation to lytic enzyme and antibiotic production, cuticle degradation, production of growth substances and fixation of nitrogen.

Examples are given of the effect on pathogenic fungi of diffusible toxins from leaves and inhibitors associated with surface wax. Treatments of leaves that remove or reduce surface wax can result in a stimulation of spore germination of some pathogenic fungi. The possible occurrence of phytoalexins on leaf surfaces prior to entry of pathogens into leaves is discussed in relation to differences in host‐