. Journal of Agricultural Research. take part in the formationof aecidiospores. Newcombe {8) and Clinton (j) have given practicallythe only accounts which deal with the mycelium and haustoria of theorange-rusts in the host tissues. Both authors used the infected black-berry as the subject of investigation. Newcombe did not study sectionsof the roots, confining his attention to i6 cm. of an infected blackberrycane. He discovered that the bulk of the mycelium was to be found inthe pith of the stem, noting hyphae in a medullary ray at one found mycelium in the fundamental tissue of
. Journal of Agricultural Research. take part in the formationof aecidiospores. Newcombe {8) and Clinton (j) have given practicallythe only accounts which deal with the mycelium and haustoria of theorange-rusts in the host tissues. Both authors used the infected black-berry as the subject of investigation. Newcombe did not study sectionsof the roots, confining his attention to i6 cm. of an infected blackberrycane. He discovered that the bulk of the mycelium was to be found inthe pith of the stem, noting hyphae in a medullary ray at one found mycelium in the fundamental tissue of the growing point,and although in old stems the hyphae were confined to the pith, theysometimes occur in the cortex and in the phloem of the bundles in youngand growing shoots. He states that— mycelial threads are present from the upper parts of the roots running through thestem into the uppermost leaves showing signs of infection * * *. Frequentlyplants are found in which the new shoots are affected but the old ones are free. In. Fig. I.—At the left, growth of shoot H from root runner. A, in April. At the right, same plant in Octo-ber; B, root crown; small central pith ?would be found at E; horizontal roots, C, which happened todevelop in this case do not ordinarily appear the first year. such case the mycelium is found in the former only * * *. Sections of roots, ex-cept in the neighborhood of the merging of root and stem, do not show the mycelium. Intercellular hyphae without septa or nuclei and the simpler types ofhaustoria are figured. MYCELIUM IN THE BLACKBERRY Clintons account of the distribution of the mycelium is correct ingeneral if applied to blackberries which have been infected for at leasttwo years, except when he states that the roots of an infected plant donot show any mycelium other than in the transition zone where root andstem join. The writer has found that hyphae invade the roots of theblackberry very extensively, a fact which accounts for the rapid spr
Size: 2299px × 1087px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, bookidjournalofagricul25assouof
