File:Contributions from the Botanical Laboratory and the Morris Arboretum of the University of Pennsylvania, vol. 14 (1934) (20695260541).jpg

Title: Contributions from the Botanical Laboratory and the Morris Arboretum of the University of Pennsylvania, vol. 14
Identifier: contributionsfro14univ (find matches)
Year: 1934 (1930s)
Authors: University of Pennsylvania. Botanical Laboratory; University of Pennsylvania. Morris Arboretum
Subjects: Botany; Botany
Publisher: Philadelphia : (s. n. )
Contributing Library: Penn State University
Digitizing Sponsor: Lyrasis Members and Sloan Foundation

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Fig. 4. T)rmalium pullnlans (\i^ \\-tr\- at,. ^ left i, the ty,,i,-.nl f„rm. ' IS. See io, t 'nLl, ^ ,!?"' f "'!'"»»;."'« spore in tl.e upper in li.;„i,l ,.„ltn,e. J). X,„lose Inpl,,,.. E Tvne', , f 1 • *""»""'""K >>o';,"r; ean;e"rid;)'r'"'^""' *" "" Ai M it I 13 were satisfactorily demonstrated in unstained sections. No hypliae were observed in the root sections, but clironiatie Tonda-Wki^ liyiiliae were abun- dant in the pith of the wood taken near a twelve-year-old node (Pio- 4 F) and occasionally penetrated the wood rays. Hyphae occurred both iiiter- and nitra-cellularly in the pith, and were observed enterino- pith cells through the simple pits in the walls. Minute hyphae also occurred in the procambuim and primary xylem of precocious buds, but were not found in the uiulifferentiated tissue of the promeristem toward the apex of the bud. Such liyphae appeared to be entirely intercellular. There was no evidence of destruction of cells or of the occlusion of vessels in any of the infected material. INOCULATIONS A suspension of conidia of Dcmatium pullulans in distilled water Avas used to inoculate a series of potted red pines 5 yeai-s of age. These trees were brought into the greenhouse from coldframes in earFy January and inoculated about a week later. Seasoiud growth was initiated in the trees, in most cases, by the second week of February. The conidial suspension Avas introduced into the bud, and into the phloem and pith of the stem by means of a liypodermic needle. Distilled water alone was injected into 3 trees of the series to serve as a control. The site of the needle puncture was ringed with a colored wax pencil, and 5 weeks after inoculation the buds and sec- tions of the stem were surface-sterilized, split longitudiually, and placed in tubes of nutrient agar. Sections of the stem were taken from the site of the inoculation and at points 1 aiul 2 cm. above and below it. Each tree bore 3 inoculations: in the terminal bud; 1 to 2 in. below the bud; and 8 to 14 in. below the terminal. D. puUulanH was recovered from all of these sites and, in some cases, from sections 1 and 2 cm. above and below the inoculation. Anotlier series of potted pines was inoculated by the following method. A small area of the stem was surface-sterilized with 70 per cent alcohol and a slight wound was made in the bark with a sterile nee. puJJuJans from the stem in the manner previously described. The failure of I). puJhdnns to develop in any of these cultures leads to the conclusion that it is uuable to enter the tree through wounds in the bark or cortical parenchyma. Since resin canals are abundant in the latter tissue, it is possible that the copious resinous exudation may have a fungicidal action. DEMONSTRATION OF A HROWTII SUBSTANCE PRODUCED BY DEMATIUM PULLULANS Dcmatium pullulans when crrown in liquid cnltuTv produces abundant INTENTIONAL SECOND EXPOSURE

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