Soluble Sugar Concentrations 

 in Needles and Bark of 

 Western White Pine in 

 Response to Season 

 and Blister Rust 



Neil E. Martin 



INTRODUCTION 



Qualitative and quantitative changes in soluble carbohy- 

 drates within conifer tissues occur throughout the year 

 (Kozlowski and Keller 1966; Little 1970; Parker 1959; 

 Zimmerman 1974). These changes are especially evident as 

 responses to seasonal use and synthesis. Usually, mono- 

 saccharides and disaccharides predominate in needles and 

 bark during the spring. As the flush of growth ceases and 

 the newly expanded organs gain in net photosynthates, 

 simple sugars are converted into oligosaccharides, illus- 

 trated in increases in raffinose and stachyose. Oligo- 

 saccharides characterize dormant conifer tissues. They do 

 not remain indefinitely as storage molecules but are 

 metabolized when ambient temperatures induce rapid 

 growth the following spring. 



Pathogens influence the metaboHsm of their host's 

 tissues. This phenomenon has been studied extensively in 

 many annual plant-obligate pathogen interactions and is 

 known to include changes in respiration rates, photosyn- 

 thesis rates, and qualitative and quantitative changes in 

 metabolite pools (Brown 1936; Durbin 1967; Goodman and 

 others 1967; Martin 1972; Schoeneweiss 1975; Siddiqui 

 and Manners 1971; Welch and Martin 1975). Conversely, 

 the metabolic or nutritional status of the host is known 

 to influence the performance of some of its pathogens 

 (Grainger 1956; Huber and Watson 1974; Schoeneweiss 

 1975). Changes in host physiology, such as those accom- 

 panying maturation or induced by climatic stimuli, may 

 favor disease development (Allen 1966; Horsfall and 

 Dimond 1957). In addition, the physiology of specific mor- 

 phogenesis in the host appears necessary for, or is at least 

 coincidental with, fungus morphogenesis. Chilling for 90 

 days at 2 °C satisfies the dormancy requirements and in- 

 duces bud elongation in the white pine host; however, 

 aecia production of Cronartium ribicola J.C. Fisch. com- 

 mences only after, but not during, host dormancy (Wicker 

 and Harvey 1969). 



Because the soluble carbohydrate content of host con- 

 ifers in the temperate zone reflects seasonal host physi- 

 ology and because these sugars are also used by the 

 obligatory blister rust fungus, it seemed that soluble sugar 

 levels would be a sensitive measure of host and parasite 

 demands. The objective of this research was to measure 



the effects of C. ribicola J.C. Fisch. and of seasons on the 

 amounts of certain soluble sugars in the needles and in the 

 bark of Pinus monticola Dougl. 



MATERIALS AND METHODS 



We selected 40 trees in a second-growth stand of 14- to 

 16-year-old western white pine growing on western white 

 pine site 90 in an Abies grandis/Pachistima myrsinites 

 habitat type (Daubenmire and Daubenmire 1968). This 

 stand is 72 km east of Moscow, ID, in the Badger 

 Meadows area of the East Fork of Potlatch Creek. We 

 selected 20 trees with rust-infected stems and 20 with 

 uninfected stems for uniformity in growth, size, habitat, 

 and competition. Each infected tree had a canker in the 

 lower half of the main stem that girdled 30 to 50 percent 

 of the stem circumference. To alleviate the effects of 

 branch infections on needle analysis, all branch cankers 

 were removed 2 months before the first sampling and 

 whenever additional infections became visible thereafter. 



Each season, two or four cankered and canker-free trees 

 were harvested for bark and needle samples. Bark was 

 sampled at four locations on the diseased trees (Welch and 

 Martin 1974): (1) sporulating areas: areas of blister rust 

 cankers where pycnia and aecia are currently produced, 

 (2) yellow margins: yellow canker boundary, (3) proximal: 

 green bark proximal to the cankers but at least 1 cm away 

 from the yellow margin, and (4) distal: green bark distal to 

 a canker (always in the next higher growth segment to 

 that of the canker). Bark was also sampled at two com- 

 parable bole locations on healthy trees. Although four 

 diseased trees were individually sampled for needles in the 

 field, the pulverized and freeze-dried samples of two trees 

 had to be pooled to provide approximately 1 gram of 

 freeze-dried tissue for analysis. 



Three age classes of needles were sampled at random 

 within each tree. Current-year, 1-year-old, and 2-year-old 

 needles were sampled randomly from throughout the live 

 crowns without regard to location of the bole canker. 

 Three-year-old needles became senescent in June and were 

 not sampled. 



All samples were collected, quick-frozen on dry ice, and 

 taken the same day to the laboratory where they were 

 processed. Soxhlet extraction of all samples, clarification, 



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