Potential for pH to Limit Oriental Bittersweet Invasion in MN Celastrus orbiculatus Heather Pagelkopf August 14, 2013

Botanic Description Deciduous climbing woody vine Up to 66’ long Large root system sends up new shoots Flowers borne on axillary cymes (clusters along length of vines) Bright ripe fruit bright red with yellow capsules

Celastrus scandens NATIVE Celastrus scandens NATIVE Celastrus orbiculatus INVASIVE Celastrus orbiculatus INVASIVE Ripe fruit capsules orange with red berries containing <1 seed Flowers found on terminal panicles Botanic Description Ripe fruit capsules yellow with red berries containing > 5 seeds Flowers found on axillary cymes

o Infests forests, grasslands and urban areas o Shades out and smothers low- lying plants

o Girdles limbs and trunk, eventually causing tree death if phloem is damaged o Weighs down limbs and trunk, causing breakage o Reduces number of native Celastrus scandens through competition and hybridization

Invasive Properties Extensive root system – regenerates asexually Hybridization with native C. scandens Faster growth than native liana  Up to 3 m annually

Invasive Properties Exhibits “sit and wait” growth strategy  Tolerance to wide range of light intensities Abundant seed production High rates of germination and establishment

Possible Limits to MN Invasion ~ 4.6 to 7.1~ 4.1 to 7.9

Soil Preferences Origin data hard to obtain Literature suggests circumneutral soil preference (6.5 to 7.5) Infestations in MN:  Winona – 6.56  Red Wing – 6.81 Winona Red Wing Minneapolis St. Paul

What Soil pH is Preferred for Growth? Research Questions: Is high pH a limiting factor for C. orbiculatus distribution, or has bittersweet simply not yet spread to regions with high pH? What soil pH values in Minnesota will be suitable for Celastrus orbiculatus seedling vigor?

 Pre-Germinated Seeds taken from Winona, MN in Nov  Transplanted into Ebb and Flow Hydroponic Rockwool System  Three pH Nutrient Solutions: 6.5, 7.2, and 7.9  Watered and drained every weekday with solutions and flushed with deionized water when EC of drained solution > 3.5 millimhos/cm

Seedling Deaths: (After 27 Days)  pH 6.5 = 8  pH 7.2 = 32  pH 7.9 = 61 Chlorosis:  pH 6.5 – very green  pH 7.2 – slightly chlorotic  pH chlorotic

Chi-Square Analysis of Seedling Deaths Parenthesis indicate expected values. χ 2 = ; df = 2 α <  We cannot conclude that seedling death and pH treatment are independent of one another.  Therefore pH is somehow affecting seedling vigor.

Implications and Further Analysis Our study suggests a relationship between soil pH and seedling vigor. Regions of MN with soil pH higher than 7.2 will likely cause some decline in seedling vigor if C. orbiculatus establishes there. Continued Analysis:  Comparison of leaf chlorophyll levels  Comparison of root and shoot biomass Other Future Study:  Replicated trial using narrow range of pH (e.g 7.5, 7.6, 7.8, and 7.9)  Similar trial using soils obtained from different regions of MN with varying soil pH

Thank You!