Comparative Anatomical Effects of the Curly-Top and Aster-Yellows Viruses on the Flax Plant

An anomalous form of mycoplasma-like bodies in periwinkle infected with the sandal spike agent

“…The latter cells may be comparable to the so-called necrotic cells. It should be pointed out that in classical literature the occurrence of necrotic cells in the sieve element was repeatedly reported as a characteristic internal symptom of 'yellows' diseased plants (Girolami, 1955;Rasa and Esau, 1961). The true nature of the necrotic cells is still unknown.…”

Anatomic effects of barley yellow dwarf virus and maleic hydrazide on certain Gramineae

“…Among the viruses promoting hyperplastic growth, those inducing the diseases called curly top (e.g., Esau, 1941), aster yellows (Girolami, 1955), bunchy top of banana (Magee, 1940), and phloem necrosis of elm (McLean, 1944) have been found exhibiting their first anatomic effects in cells located next to the first mature sieve elements at a given level of root or shoot. With regard to the viruses inducing a necrosis in the phloem without any pronounced growth changes preceding the death of cells, Schneider (1945) observed a necrosis of the earliest sieve elements in the shoots of the peach infected with the virus of the buckskin disease.…”

Curly top symptoms in an inoculated cotyledon of the sugar beet

“…Necrotic obliteration is not restricted to plants affected by viruses, but may be induced by various other conditions and agents (e.g., Schneider, 1945Schneider, , 1954. This symptom seems to be less specific than the hyperplastic changes induced by the curly top and aster yellows (Girolami, 1955) viruses. AIthough hyperplasia can be induced in the phloem by certain growth-regulating substances (Eames, 1950), the resulting tissue has the structure of parenchyma, whereas, in plants affected by the curly top and aster yellows viruses, the hyperplastic tissue differentiates into a mass of abnormal sieve elements (Esau, 1935(Esau, ,1941Girolami, 1955).…”