Diseases of plants induced by Diseases of plants induced by cryptogamic parasites; introduction to the study of pathogenic Fungi, slime-Fungi, bacteria, & Algae diseasesofplant00tube Year: 1897 22 REACTION OF HOST TO PARASITIC ATTACK. of Other examples, since many of these will be referred to again in other chapters, particularly when hypertrophy is under consi- deration. § n. EFFECT OF PARASITIC FUNGI ON THE FORM OF THE HOST-PLANT. 1. Arrest of growth, and Atrophy. While a large number of fungi produce more or less extensive enlargement of parts of their host, others cause arrest of organs,
Diseases of plants induced by Diseases of plants induced by cryptogamic parasites; introduction to the study of pathogenic Fungi, slime-Fungi, bacteria, & Algae diseasesofplant00tube Year: 1897 22 REACTION OF HOST TO PARASITIC ATTACK. of Other examples, since many of these will be referred to again in other chapters, particularly when hypertrophy is under consi- deration. § n. EFFECT OF PARASITIC FUNGI ON THE FORM OF THE HOST-PLANT. 1. Arrest of growth, and Atrophy. While a large number of fungi produce more or less extensive enlargement of parts of their host, others cause arrest of organs, crippling, impoverished nutrition, and even atrophy of an extreme kind. Incompletely developed organs of this kind may originate even where the fungus in possession produces only local hypertrophy. In- teresting examples are presented by many species of Synchytrmm { S. and S. cmi- mones). The former is endo- phytic in Taraoxicum, and exerts a stimulus resulting in increased growth, not limited to the single cell attacked, but ex- tending to neighbouring cells, which, in consequence, multiply and form a ring-like swelling round it. The leaves as a whole, however, are poorly developed, so that the lamina in very extreme cases may be represented only by the midrib and narrow margin (Fig. 4); while on leaves attacked on one side, that side alone is stunted, the other is normal. Taraxacum leaves badly attacked by Puccinia are not at all deformed, whereas those of Anemone show striking arrest of growth (Fig. 190). Leaves of Cirsium attacked by Piccinia snaveolens exhibit an arrest of the same kind, remaining less divided and of softer texture (Fig. 186). Flowers affected by parasitic fungi present many striking malformations. Magnus describes such a case in Anemone Fig. i. — taraxaci. Partialatroiihy of laminae of Taraxacum officinale. About i natural size. (v. Tubeiif phot.) Magnus, ' Einfluss v. Parasiten auf d. Ausbildung d. befalleneu PflAii
Size: 1278px × 1565px
Photo credit: © Bookend / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: archive, book, drawing, historical, history, illustration, image, page, picture, print, reference, vintage
