JOBNAME: horts 41#7 2006 PAGE: 1 OUTPUT: October 24 19:41:43 2006 tsp/horts/127877/01652 HORTSCIENCE 41(7):1662–1666. 2006. (Douds et al., 1995; Halladin, 1991). A goal of this study was to test rigorously the effects Sciadopitys verticillata of water soak pretreatments on rooting suc- Propagation of cess of hardwood and softwood stem cut- tings. In addition, experiments were designed (Thunb.) Sieb. & Zucc. by Stem to examine the influences on rooting of 1) different source trees, 2) source trees of Cuttings and Properties of Its different heights and ages, 3) source trees growing under different sunlight conditions, and 4) softwood and hardwood cuttings. Latex-like Sap Evidence from other species suggests the David I. Yates, Brandi L. Earp, and Foster Levy1 natural function of plant latexes and resins Department of Biological Sciences, East Tennessee State University, Box may be as defenses against pests and patho- gens (Dussourd and Eisner, 1987; Farrell 70703, Johnson City, TN 37614 et al., 1991; Lokvam et al., 2000; Rukachai- Elaine S. Walker sirikul et al., 2005). Observations that S. verticillata is relatively disease and pest free, James H. Quillen Veterans Affairs Medical Center, Mountain Home, TN and the wood is resistant to decay, suggest S. 37684; and Division of Infectious Diseases, Department of Internal verticillata may produce natural compounds Medicine, James H. Quillen College of Medicine, East Tennessee State that inhibit microbial growth. Based on these University, Johnson City, TN 37614 observations, we postulated that the latex of S. verticillata may possess antimicrobial Additional index words. Japanese umbrella pine, antimicrobial, rooting activity that would be suitable for broader applications. Consequently, another goal of Abstract. To improve the success of vegetative propagation of Sciadopitys verticillata, stem the study was to test crude latex extracts for cuttings were subjected to three treatments designed to minimize the accumulation of in vitroantimicrobial activity against a suiteof a latex-like sap at the cut ends of stems. A 24-hour soak in water before a hormone dip bacterial species that occupy diverse habitats. significantly enhanced rooting success and root mass. The water soak pretreatment was more beneficial to hardwood cuttings compared with softwood cuttings. Cuttings from shade-grown source trees showed the highest rooting success, but source tree age, height, and place of origin were not important factors. The water-insoluble latex-like sap had Materials and Methods strong antibacterial activity against 3 of 11 bacterial species tested, but activity was not Stem cuttings. Hardwood (March) and related to bacterial Gram reaction or the bacterial natural environment. In contrast, pine softwood (June) cuttings were taken from resins and latexes from selected angiosperms showed no antibacterial activity. The six landscape trees growing at various sites in antibacterial component of the Sciadopitys latex-like sap was heat stable and therefore three counties (Carter, Unicoi, Washington) probably not protein based. in northeast Tennessee. Source trees included two each from the small, medium, and tall height classes (Table 1). None of these trees Japanese umbrella pines [Sciadopitys ver- plant because of limited availability and high were known to be derived from the same ticillata (Thunb.) Sieb. & Zucc.] are highly cost (Goodhart, 2000). source material (Table 1). Stem cuttings were desirable landscape trees because of their S. verticillata differs from all other coni- taken during the morning on overcast days to pleasing full conical shape, green color fers in its production of a viscous, milky minimize drying during transport and prepa- throughout the year, relatively slow growth colored, latex-like, nonresinous sap (Langen- ration. The number of cuttings per tree varied rate for a conifer, and absence of troublesome heim, 2003). The latex is produced in laticifer from 40 to 100 per season, depending upon pests or pathogens. Propagation of S. verti- ducts and is secreted from wounds such as the tree size. Cuttings averaged 15 cm in cillata has been difficult and limited in scope those induced by stem cuttings. When ex- length and had approximate average diame- because of poor seed germination and slow posed to air, the latex quickly hardens and the ters of 0.5 cm. Immediately before pretreat- growth of resultant seedlings (Rudolf and resultant seal of the wound is hypothesized to ment, cuttings were laterally scored 3 cm Owston, 2003; Waxman, 1957, 1960). Al- provide protection from pathogens (Farrell from the basal end. though it has been nearly three decades since et al., 1991; Shukla and Krishna Murti, All cuttings were dipped in a 1:5 (by Waxman (1978) described techniques that 1971). However, there have been suggestions volume) dilution of Dip-N-Grow hormone resulted in an extremely high success rate in that this latex-like substance plays a primary solution (a.i. of 1.0% indole-3-butyric acid rooting stem cuttings of S. verticillata, more role in the inhibition of adventitious roots and 0.5% 1-napthaleneaceticacid) for 1 min recent studies have failed to replicate Wax- (Waxman, 1978). combined with either no other treatment man’s findings (Douds et al., 1995; Halladin, Some reports on optimal techniques for (control) or preceded by one of three pretreat- 1991). Hence, the species is still considered vegetative propagation of S. verticillata sug- ments: a fresh basal cut was made followed difficult to propagate and remains a specialty gested that the efficiency of success in root- by soaking in water for 24 h (water soak), ing stem cuttings could be improved by a fresh basal cut was made underwater soaking the cut end of the stem in water for followed by soaking in water for 24 h (water Received for publication 31 May 2006. Accepted either 2 to 3 h (Tu and Sheng, 1980) or 24 to cut and soak), or a fresh basal cut was made for publication 28 July 2006. 48 h before hormone treatment and planting followed by soaking 24 h in a 0.5% solution This material is the result of work supported with (Flemer, 1961; Waxman, 1978). The water of the detergent Tween-20 (detergent soak). resources and the use of facilities at the James H. soak pretreatment was intended to ameliorate These treatments were designed to minimize Quillen Veterans Affairs Medical Center. the hypothesized inhibitory effects on rooting coagulation of latex at the cut ends of stems. We thank Barbara Ownley for cultures of plant of the latex-like sap by channeling the latex The detergent soak was included in an at- pathogens, John Laffan for cultures of soil bacteria, away from the cut end of the stem. However, tempt to solubilize the latex, an approach that Chris Liu for translation, owners of source trees for permission to take cuttings, and Cecilia McIntosh, the success rate appeared to depend strongly was based on reports that plant latexes may Dhirendra Kumar, and an anonymous reviewer for upon the source tree. Moreover, more recent be lipid soluble (Langenheim, 2003). After insightful comments. studies have failed to detect beneficial effects treatments, cuttings were placed to a depth 1To whom reprint requests should be addressed; of a water soak pretreatment and have re- of 7 cm in soilless media composed of 1 e-mail [email protected] ported far more modest rooting success rates peatmoss : 1 perlite (by volume) in tree trays 1662 HORTSCIENCE VOL. 41(7) DECEMBER 2006 JOBNAME: horts 41#7 2006 PAGE: 2 OUTPUT: October 24 19:41:44 2006 tsp/horts/127877/01652 Table 1. Characteristics of source trees used for stem cuttings. highly significant season, treatment, and light No. of cuttings environment main effects (Table 2). The Height per treatment percentage of rooting was significantly high- Tree Height (m) class Age (y) Light per season Sourcez er for hardwood cuttings (rooting means: LN 1 Small 15 Sun 10 Oregon hardwood, 33.5%; softwood, 22.8%), a pat- MM 2 Small 12 Shade 15 Oregon tern observed within all treatments (Fig. 1). HC 3 Medium 20 Sun 10 Tennessee Roots ranged from short, single, unbranched FL 4 Medium 15 Sun 10 Oregon primary roots to well-developed, long (>15 GM 8 Tall <30 Shade 25 New Jersey cm), branched root systems (Fig. 2). The size VA >10 Tall >60 Sun 30 Japan z of the tree from which cuttings were taken All currently growing in northeast Tennessee. had no significant effect on rooting efficiency (means: small, 40%; medium, 29%; tall, with cells 10 cm deep · 5 cm square. Cutt- bacterial lawns. The following treatments 34%; heterogeneity c2 = 2.58, df =2,P = ings were placed under intermittent mist of were tested: 0.28; Fig. 3). A similar absence of an effect 10 s on and 3 min off during daylight hours 1. Control (0.15% NaCl) would be observed if age was substituted for in a greenhouse with temperatures of 23 to 2. Bleach control: a nonsterile pencil was height because age and height were strongly 30 °C and year-round 50% shade cloth. surface sterilized as described earlier correlated (r = 0.90, t = 4.08, df =4,P = 0.02). Small numbers of cuttings were visually and touched three times to the media. Within each cutting season, the two 24-h inspected monthly for rooting. Rooting suc- This treatment was designed to show water soak pretreatments yielded signifi- cess was scored 6 months after planting, at that the surface sterilization of wood cantly more rooted cuttings compared with which time cuttings were gently separated was not inhibitory to the bacterial lawn. untreated controls and cuttings soaked in from the media by hand, visually inspected, 3. Sap suspension at room temperature detergent (Fig. 1). Thus, the benefit of a water and assigned to one of the following five 4.