Table of ContentsIntroductionFaba
beanInstrumentationBiologyConclusionAbout Carl Zeiss
Grain legumes are highly significant in global agricultural activities,
however information on the composition, structure, and functioning of their open
style and solid stigma is limited.
Global food production is underpinned by plant breeding programmes based on
essential crops such as the broad bean (Vicia fava L.), soybean, pea, and the
common bean. A clear insight into the mechanism of pollination in such species
enhances the effectiveness of these programmes.
The faba bean is especially suited for study because it produces a large
number of large flowers with straight styles that are easy to dissect and both
autofertile and autosterile lines. Autofertile lines do not need a pollinating
insect but do not have very large yields. Autosterile lines do need a
pollinating insect and have relatively high crop yields.
Faba Bean Studies
The main objective for plant scientists is to compare autosterile and
autofertile lines so that crosses between the two lines can be obtained. The
overall objective is increased food production. In this application note the
development of the faba bean stigma was observed by using a scanning elctron
microscope in the days leading to anthesis (pollination).
LS 15 SEM with variable pressure (VP) feature and a variable pressure
secondary electron (VPSE) detector was used for these studies of pollination
biology. In addition, the SEM was equipped with a Coolstage and the images
presented in this note were obtained with the stigma cooled to approximately
To minimize possible damage to the specimens, a low pressure of about 30 Pa
of air was used. This extremely low pressure is adequate to compensate for
specimen charging and to trigger a gas phase scintillation signal for the VPSE
detector. The Coolstage, shown in Figure 1, is a Peltier device, which can
minimize the specimen temperature. Long periods of SEM imaging are then possible
since hydration of the specimen is maintained.
Figure 1. Coolstage fitted to the EVO® Cartesian
Anthesis is that stage of maturity of the stigma at which pollen that reaches
its can cause pollination of the flower. The stigma undergoes physical changes
in the days before anthesis and this project records the changes. The SEM offers
an easy way to image the three dimensional surface structure of the stigma.
Stigma samples were obtained from D07 plants in the days before anthesis.
Figure 2 and 3 show the autosterile D07 line three days and two days before
Figure 2. Structural Outline of a stigma from the
autosterile line D07 at three days pre anthesis. The stigmatic cuticle and
papillae were intact and no exudate was released.
Figure 3. Structural Outline of a stigma from the
autosterile line D07 in faba bean at two days pre anthesis. The stigmatic
cuticle was intact and no exudate was released.
About Carl Zeiss
Carl Zeiss has more than 160 years of experience in optics has
in order to lay the foundation for pioneering electron and ion beam microscopes
from Carl Zeiss. Superior integration of imaging and analytical capabilities
provides information beyond resolution, making sure that the minutest details of
these biological samples are obtained. About Carl Zeiss
The Carl Zeiss NTS (Nanotechnology Systems) Division is a value
adding integral part of Carl Zeiss developing, producing, selling and servicing
SEM, TEM, and Particle Beam instruments designed to set unique high quality
standards and to provide customer focused solutions for the Semiconductor,
Material Analysis and Life Science application fields worldwide. Development and
production facilities are based in Oberkochen (Germany), Peabody, MA (USA) and
This information has been sourced, reviewed and adapted from
materials provided by Carl Zeiss NTS.
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