Mulch Type, Mulch Depth, and Rhizome Planting Depth for Field-grown American Mayapple

Abstract

<jats:p>American mayapple (<jats:italic>Podophyllum peltatum</jats:italic> L.) is a rhizomatous herbaceous perennial found in wooded areas of eastern North America and is a source of the pharmaceutical compound podophyllotoxin. To explore the possible domestication of this species, this research examined strategies for establishing mayapple in field plantings using organic mulches. Mayapple rhizome segments were harvested from the wild and transplanted to raised beds in northern Mississippi in Fall 2001. Two types of mulch (pine bark or wheat straw), two depths of mulch (7.5 or 15 cm), and two planting depths (0 or 5 cm) of rhizome segments were examined in a factorial arrangement and randomized complete block design. Data were recorded during spring of 2002 and 2003. Shoot number was not affected by mulch depth, but there was a significant interaction between mulch type and rhizome planting depth. Rhizome segments planted 0 cm deep and covered with straw mulch produced about 30% fewer shoots compared to any of the other treatment combinations. Number of emerging shoots was also affected by year, with a 33% increase in shoots from 2002 to 2003. Total leaf area and total leaf dry weight were not affected by mulch depth, but there was a significant three-way interaction between mulch type, rhizome planting depth, and year. During 2002, treatment combinations were not different, but during 2003 rhizome segments planted 0 cm deep and covered with straw mulch produced less leaf area and leaf dry weight than any of the other treatment combinations. The ratio of sexual shoots to total shoots was affected by year, with a higher ratio of sexual shoots occurring in 2002 than 2003. Grasses established in bark mulch to a greater extent than in straw mulch in 2002, but weed control was excellent for all treatments in 2003. These results indicate that rhizome segments planted 0 cm deep and covered with straw mulch consistently produced fewer shoots with less leaf area and dry mass compared to any other treatment combination. We preferred bark mulch, but we can recommend either bark or straw mulch for the purpose of establishing field plantings of american mayapple in full sun as long as rhizome planting depth is 5 cm. There was no difference between the two mulching depths used in this study; therefore, a mulch depth of 7.5 cm can be recommended because of its lower cost.</jats:p>

Podophyllotoxin Content, Above- and Belowground Biomass in Relation to Altitude in Podophyllum hexandrum Populations from Kumaun Region of the Indian Central Himalaya

“…Leaves can be a continuous source of the compound and determination of podophyllotoxin content in leaves showed much variation ranging from 0 ± 56 mgg -1 [8], [9]. Recent research showed that the species is relatively easy to manipulate using common horticultural practices [10], [11]; the timing, frequency of harvest and sun/shade cycle affected the growth and overall podophyllotoxin content of P. peltatum during cultivation trials [12], [13]. The limited availability of wild P. hexandrum is attributed mainly to its long juvenile phase, poor fruit and seed set, uneven and poor germination and overall slow regeneration.…”

Juneberry Growth Is Affected by Weed Control Methods

“…However, through the course of the growing season, some straw was wind blown, which reduced the 3-inch straw layer and resulted in a thinner layer of mulch that was less effective in weed suppression. Hipps et al (2004) reported little weed emergence with a 15-cm-deep straw mulch treatment, whereas Cushman et al (2005) reported excellent weed control with wheat straw at 7.5-and 15-cm depths, and recommended a mulch depth of 7.5 cm because of its lower cost. A thinner wheat straw layer was used in the current study because of concerns of retaining too much moisture with the fine-textured soil and the lower soil temperature effect of plant growth.…”

“…Winter rye seed was sown by hand at 300 lb/acre in Sept. 2004 and2005 edges with 8-inch-long sod staples. The roll of flax straw mulch consists of shredded flax straw that has a binding substance added before forming a mat %0.5 inch thick.…”

Frequency and Timing of Leaf Removal Affect Growth and Podophyllotoxin Content of American Mayapple in Shade

“…If domesticated, it is expected that commercial plantings would use only accessions with the highest levels of the compound, thus providing the highest return to growers of specialty crops serving the pharmaceutical industry (Meijer, 1974;Moraes et al, 2000). Recent research showed the species to be relatively easy to manipulate using common horticultural practices (Cushman et al, 2005a(Cushman et al, , 2005bCushman and Maqbool, 2005). In addition, increasing levels of shade were reported to result in decreasing podophyllotoxin content (Cushman et al, 2005b;Moraes et al, 2005).…”