[APWG] [ma-eppc] Lonicera japonica - allelopathic effects on pine regeneration

[Marc Imlay]

Here is an indication that the Lonicera japonica allelopathic
effects apply to other Lonicera and impact other plants.

Marc

----- Original Message -----
From: "LawrenceT Beckerle" <lawrencetbeckerle at yahoo.com>
To: "Marc Imlay" <ialm at erols.com>
Sent: Thursday, March 10, 2005 1:50 PM
Subject: Re: [ma-eppc] Lonicera japonica - allelopathic effects on pine
regeneration


In December I dug out about 30 asiatic bush
honeysuckle shrubs on dad's farm.  I noticed that dead
black locust roots in the area where I grubbed out the
honeysuckle (probaly Morrow or Tartarian).  Those dead
roots plus the lack of vegetation that I remember form
my childhood suggest to me that the non-native bush
honeysuckle's also have allelopathic properties.

Lawrence T. Beckerle


----- Original Message -----
From: <Jil_Swearingen at nps.gov>
To: <apwg at lists.plantconservation.org>; <ma-eppc at yahoogroups.com>; "Pete
Egan" <Peter.Egan at osd.mil>; "Barry Meyers-Rice" <bamrice at ucdavis.edu>
Sent: Friday, March 04, 2005 11:16 AM
Subject: [ma-eppc] Fw: Lonicera japonica - allelopathic effects on pine
regeneration
Hi,

In case you'd given up on trying to manage Japanese honeysuckle, here's
some information that may rekindle your interest in targeting this plant.

Thanks,

Jil

*******************************
JIL M SWEARINGEN
Invasive Species and
Pest Management Coordinator

NATIONAL PARK SERVICE
National Capital Region
Center for Urban Ecology
4598 MacArthur Blvd., NW
Washington DC 20007
Phone/ 202-342-1443, ex. 218
Fax/ 202-282-1031
Jil_Swearingen at nps.gov

WEEDS GONE WILD Web Page
http://www.nps.gov/plants/alien

----- Forwarded by Jil Swearingen/NCR/NPS on 03/04/2005 11:12 AM -----

                      Sue Salmons
                                               To:       Jil
Swearingen/NCR/NPS at NPS, Ron Dean/NCR/NPS at NPS, Cynthia
                      03/03/2005 12:38          Wanschura/NCR/NPS at NPS
                      PM EST                   cc:
                                               Subject:  Lonicera japonica




The attached article was sent to me by Dan Kjar, the G'tn. grad. student
who is putting together the invertebrte database for the region. It's a
little scary to think that the leaf litter of Japanese honeysuckle may be
allelopathic. The research only tested it on pines, but...
SueS
(See attached file: skulman2004.pdf)

Sue Salmons
Resource Management Specialist - Vegetation
Rock Creek Park
202-895-6077





Skulman et al.: Allelopathic interference of Japanese honeysuckle x 433

Weed Science, 52:433-439. 2004

Evidence for allelopathic interference of Japanese

honeysuckle ( Lonicera japonica) to loblolly and shortleaf

pine regeneration

B. W. Skulman

Corresponding author. Department of Crop, Soil,

and Environmental Sciences, University of Arkansas,

1366 West Altheimer Drive, Fayetteville, AR 72704;

bskulman at uark.edu

J. D. Mattice

Department of Crop, Soil, and Environmental

Sciences, University of Arkansas, 1366 West

Altheimer Drive, Fayetteville, AR 72704

M. D. Cain

USDA Forest Service, Southern Research Station,

Forest Resources Building, University of Arkansas at

Monticello, P.O. Box 3516, Monticello, AR 71656-

3516

E. E. Gbur

Agricultural Statistics Lab, AGRX-101, University of

Arkansas, Fayetteville, AR 72701

Japanese honeysuckle presents a serious problem to the economically
attractive natural

regeneration of loblolly and shortleaf pine. This research investigated the
potential

allelopathic interference mechanisms of Japanese honeysuckle in relation to

pine regeneration and growth, which may provide insight into overcoming this
problem.

The allelopathic potential of root exudates and leaf litter from Japanese
honeysuckle

was tested against loblolly and shortleaf pine seedlings. When Japanese

honeysuckle and loblolly pine seedlings were grown using the same irrigation
reservoir,

there was no significant effect on the growth of either pine species.
Exudates

of Japanese honeysuckle grown as a pure culture in donor cups also produced
no

growth effects on pure-cultured pine seedlings grown in acceptor cups. In
other

assays, aqueous extracts of Japanese honeysuckle leaf tissue were toxic to
duckweeds

at concentrations well below levels where plasmolysis might cause effects.
When

Japanese honeysuckle leaf tissue was added to soil at a rate of 2 g tissue
100 g21

soil, mean seedling height at 128 d after planting was reduced by as much as
40%.

Moreover, pine seedlings grown in the presence of Japanese honeysuckle
tissue exhibited

significant chlorosis of the shoot and needles. Gas chromatography-mass

spectroscopy analyses and high-performance liquid chromatography of Japanese
honeysuckle

leaf tissue aqueous extracts confirmed the presence of five compounds
previously

identified as possible allelochemicals: 4-hydroxycinnamic acid;
2-hydroxycinnamic

acid; 3,4-dihydroxybenzoic acid; 3,4-dihydroxycinnamic acid; and chlorogenic

acid. Results indicate that allelopathy plays at least a partial role in
Japanese honeysuckle

interference with loblolly and shortleaf pine.

Nomenclature: Japanese honeysuckle, Lonicera japonica Thunb.; loblolly pine,
Pinus

taeda L.; shortleaf pine, Pinus echinata Mill; duckweed, Lemna minor L.

Key words: Allelopathy, germination, Lonicera japonica, Pinus taeda, Pinus
echinata,

interference.

Natural regeneration of loblolly and shortleaf pine provides

an attractive alternative to artificial reforestation for

small wood lot owners of the southeastern United States.

(Cain 1985). Unfortunately, competing vegetation can have

an adverse effect on natural pine seedling regeneration. Of

particular concern is Japanese honeysuckle, which was introduced

into the United States from Asia in 1806 (Leatherman

1955). This forest weed has become established

throughout the southeastern United States and poses a serious

problem in forest regeneration efforts because of its

formation of dense mats of vegetation that interfere with

the growth of shrubs, seedlings, and saplings.

Interference is the adverse effect that neighboring plants

can exert on each other's growth (Muller 1969; Rice 1974).

The causes of interference most commonly include competition

and allelopathy. Competition is the exclusion, depletion,

or removal of one or more environmental resources

such as nutrients, water, or light. Conversely, allelopathy is

the production and release of chemicals into the environment

by living or decaying plant tissues, which inhibit or

delay the growth of neighboring plants. Allelopathy has been

observed from various weed species and is a potentially potent

factor in reduced crop growth and yields (Drost and

Doll 1980; Jain et al. 1989). Siccama et al. (1976) have

shown that vines have deleterious effects on temperate forests

when present in large numbers. Exotic vines, such as

Japanese honeysuckle, have been shown to exert negative

effects on forest vegetation and may result in a vine-dominated

disclimax (Slezak 1976). Wigham (1984) showed that

removal of vines from the trunk, branches, and ground had

a significant positive effect on the growth of sweetgum (Liquidambar

styraciflua L.) when compared with removal of

vines from the trunk and branches alone and the control

(no vines removed). In that study, the dominant vines were

Japanese honeysuckle and poison ivy (Rhus radicans L.), with

abundant wild grape (Vitis spp.), Virginia creeper [Parthenocissus

quinquefolia (L.) Planchon], and trumpet creeper

[Campsis radicans (L.) Seeman]. The increased growth of

sweetgum after vine removal from trunk, branches, and soil

was attributed to reduction in interference. However, the

study did not distinguish between competition and allelopathy.

Because sweetgum growth increased only when the

vine roots were removed, as opposed to only removal of the

vine shoots, this may be an indicator of possible allelopathic

interference.

Cain (1991) observed that, under similar vegetation management

and harvesting regimen, there was more successful

regeneration in a pine forest that contained midstory and

understory hardwoods as opposed to a similar forest occupied

by established herbaceous vegetation. In this case the