Potential for pH to Limit Oriental Bittersweet Invasion in MN

Celastrus orbiculatus

Heather PagelkopfAugust 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 scandensNATIVE

Celastrus scandensNATIVE

Celastrus orbiculatusINVASIVE

Celastrus orbiculatusINVASIVE

• 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. 2012

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 7.9 - chlorotic

Chi-Square Analysis of Seedling Deaths

•Parenthesis indicate expected values.

•χ2= 53.947; df = 2•α < 0.001

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!