Welcome to this first edition of Botany News!
- A note from the editor
- Plants grown in northern gardens: Common Juniper
- Beetle herbivory on Passiflora vines
- Coastal vegetation of Iceland
- Submit your Botany News article!
- The flower box
Vistit our website:
A note from the editor
HAPPY EASTER! Welcome to Botany News the new botanical
online e-zine. I hope you will enjoy the material
and I welcome feedback from you. If you like this
new e-zine you could let your botanical friends know
about it. Some of you are already signed up for
receiving Botany News. The future of this e-zine
depends on enthusiastic readers, willing to exchange
information on plants and events in botany.
Plants grown in nothern gardens: Common Juniper
Common Juniper (Juniperus communis) is an
evergreen woody plant with small stinging leaves. There
are separate male and female plants. In Iceland,
Common Juniper often has a creeping growth form, but
sometimes forms upright bushes. In the wild, Common
Juniper grows on heaths, cliffs and woodlands. The
berries are used as a spice.
The significance of beetle folivory for the growth of
Passiflora vitifolia. - Botany News.
March 2005. By Soffia Arnthorsdottir
Herbivory by flea beetles (Alticinae spp.) caused reduced growth of the host
plant, Passiflora vitifolia, a woody vine associated with forest gaps in
the tropical lowland rainforest. Experiments and observations were
conducted on P. vitifolia in a tropical forest in Costa Rica. Beetle herbivory on mature
Passiflora vitifolia was associated with an
increased proportion of leaf loss in the early wet
season. However, a similar negative response was not
shown in the late wet season.
When responses of plants to herbivory were compared for
the experimental plants, a higher proportion of beetle
damage was associated with reduced plant growth, shown
as a lower number of leaves on individual P.
In one experiment, where the proportion of beetle
herbivory levels was manipulated, the growth of P.
vitifolia was directly affected. Beetle herbivory on
the plants reduced their branch extension, but only when
previous damage had occurred. The negative effect of
beetle herbivory was also detected as a negative change
in leaf numbers, regardless of whether the plants had
received previous damage.
There is clear evidence of reduced growth of P.
vitifolia with increased levels of beetle herbivory.
The results show positive associations between beetle
damage and net leaf loss, a measure of the balance
between leaf formation and leaf abscission. This suggest
that beetle damage may cause leaf loss to P.
vitifolia. The correlation between beetle herbivory
and leaf loss in the early season is an indication that
beetle herbivory could be causing leaf abscission.
The beetles only cause partial damage to the leaves,
but this could result in physiological stress or
chemical changes in the leaves. Surprisingly, little
difference was found between plant responses in the
contrasting experimental habitats. However, the greater
impact of herbivory during the sunnier, early half of
the rainy season indicates that seasonal differences in
light levels could affect plant responses to damage.
The seasonally greater impact of beetle herbivory in the
early as opposed to the late season is not directly
related to higher levels of herbivory at that time.
However, it may be partly explained by a relatively
greater impact of physical factors in the late as
opposed to the early wet season. Seasonal differences
could be an indicator of the importance of internal
resources for the responses of P. vitifolia to
herbivory. After a long dry season, the plants may have
inadequate stored reserves to recover after herbivory
and this may result in reduced growth or leaf loss.
Seasonal fluctuation in resources are likely affecting
the reponse of P. vitifolia to damage.
Plants growing in natural habitats and at the
experimental site showed an identical pattern. Both
groups showed reduced growth in response to natural
levels of beetle herbivory. Plants growing in the forest
were much larger than the experimental plants. The
similar responses of large and small plants indicate
that large and small plants may have the same basic
mechanism in their response to herbivory. The size or
age of Passiflora may be correlated with plant
quality as food for herbivores or herbivore apparency to
There is evidence from the present study that previous
damage causes the plants to be more susceptible to later
damage. This conclusion indicates that herbivory acts as
a physiological stress factor on the plants. It is
concluded that beetle herbivory is important for the
growth of P. vitifolia in the tropical lowland
Coastal vegetation of Iceland
Coastal vegetation is shaped by the coastal terrain and
salinity as well as amount and frequency of flooding by
the sea. Here, you observe coastal plants well adjusted
to saline soils and often growing as succulents. Lyme
Grass (Leymus arenarius) as well as many weeds are
found on the dunes; Lyme Grass is often sown into sandy
dunes for the purpose of land restoration. Lower on the
beach you find sea weeds.
Salt marshes are a special
vegetation type by the sea, salt marshes are only found
where the sea floods the vegetation and there are muddy
river deposits, Common Saltmarsh-grass (Puccinellia
maritime) is characteristic of salt marshes in south
Iceland. The dominant vegetation is interspersed with
scattered patches of Fiorin (Agrostis stolonifera)
and Sea Plantain (Plantago maritima). Eel-grass (Zostera
marina) grows further on the muddy bottom of shallow
Submit your Botany News article!
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Submit your Botany News article!
The Flower Box
The plan is to organize a botanical course in
Iceland in 2006. A formal announcement about the
course will be made later this year. However, if
you are interested
contact us soon and let us know!
A first circular on the meeting "State of Bryophyte
Ecology 2005" is now available on the following web-site: Botany in Hungary
This section publishes brief announcements about
botany and related issues. Announcements about
meetings, excursions, courses, jobs and other important
items are consider for publication in this section.
Announcements are generally less than 300 words.
Submit your Botany News announcement!
| BOTANY NEWS is published by
Thund, Reykjavik, Iceland
March 20, 2005 -- Botany News, Issue #001