Species of flowering plant in the pea and bean family Fabaceae
The
sweet pea
,
Lathyrus odoratus
, is a
flowering plant
in the
genus
Lathyrus
in the
family
Fabaceae
(
legumes
),
native
to Sicily, southern Italy and the Aegean Islands.
[2]
It is an
annual
climbing plant, growing to a height of 1?2 metres (3 ft 3 in ? 6 ft 7 in), where suitable support is available. The
leaves
are
pinnate
with two leaflets and a terminal
tendril
, which twines around supporting plants and structures, helping the sweet pea to climb. In the wild plant the
flowers
are purple,
2?3.5 cm (
3
⁄
4
?
1
+
1
⁄
2
in) broad; they are larger and highly variable in color in the many
cultivars
. Flowers are usually strongly scented.
The annual
species
,
L. odoratus
, may be confused with the everlasting pea,
L. latifolius
, a perennial.
[3]
Horticultural development
[
edit
]
Scottish
nurseryman
Henry Eckford
(1823?1905) cross-bred and developed the sweet pea, turning it from a rather insignificant if sweetly scented flower into a floral sensation of the 19th century.
His initial success and recognition came while serving as head gardener for the
Earl of Radnor
, raising new cultivars of
pelargoniums
and
dahlias
. In 1870 he went to work for one Dr. Sankey of Sandywell near Gloucester. A member of the
Royal Horticultural Society
, he was awarded a First Class Certificate (the top award) in 1882 for introducing the sweet pea cultivar 'Bronze Prince', marking the start of association with the flower. In 1888 he set up his development and trial fields for sweet peas in
Wem
in
Shropshire
. By 1901, he had introduced a total of 115 of the 264
cultivars
grown at the time.
[4]
Eckford was presented with the RHS Victoria Medal of Honour for his work. He died in 1906, but his work was continued for a time by his son John Eckford.
More recently, the association between the sweet pea, the Eckfords and Wem has been highlighted again. In the late 1980s, the Sweet Pea Society of Wem started an annual show. Many of the street signs now carry a sweet-pea motif, and an area of the town is known as Eckford Park.
[
citation needed
]
There is also a cultivar 'Dorothy Eckford', named after a family member.
Cultivation
[
edit
]
Sweet peas have been cultivated since the 17th century and a vast number of
cultivars
are commercially available. They are grown for their flower colour (usually in pastel shades of blue, pink, purple and white, including bi-colours), and for their intense unique fragrance. They are grown by gardeners for private enjoyment or for exhibition, and in the
floristry
trade. The large, pea-shaped seeds are sown in
cold frames
in Spring or Autumn. The seeds benefit from pre-soaking or chipping with a sharp blade. The plants are also available later in the season, as young plants or
plugs
. They are grown up canes, with the new shoots being regularly pinched out to promote a bushy habit and higher flower yields. Plants typically reach heights of 1?2 metres (3 ft 3 in ? 6 ft 7 in), with the flowers appearing in midsummer and continuing for many weeks if regularly
deadheaded
.
[5]
Over 50 cultivars
have gained the
Royal Horticultural Society
's
Award of Garden Merit
.
Pests and diseases
[
edit
]
The sweet pea plant suffers from some pests, the most common being
aphids
. These insects suck the sap out of the plants, reducing growth.
Mosaic virus
is spread by greenfly, causing yellowing of leaves, distortion of new shoots, and inhibited flowering.
[6]
A pest called the
pollen beetle
, which is small, shiny and black, eats the pollen and disfigures the flowers. Other pests include caterpillars,
thrips
,
slugs
and
snails
. Another problem is
powdery mildew
; this is a white powdery coating that covers the leaves and slows down growth, and can be caused when sweet peas are planted too close to each other, sucking nutrients from the plants and stunting their growth.
[7]
The sweet pea is also susceptible to
ethylene
in quantities produced by senescing plants. Because of this, growers are encouraged to plant sweet peas away from fruit trees among other plants prone to early dieback or senescence.
Toxicity
[
edit
]
Unlike the edible
pea
, there is evidence that
seeds
of members of the genus
Lathyrus
are toxic if ingested in quantity. A related species,
Lathyrus sativus
, is grown for human consumption but when it forms a major part of the diet it causes symptoms of toxicity called
lathyrism
.
[8]
In studies of rats, animals fed a diet of 50% sweet pea seeds developed enlarged adrenals relative to control animals fed on edible peas.
[9]
The main effect is thought to be on the formation of collagen. Symptoms are similar to those of
scurvy
and copper deficiency, which share the common feature of inhibiting proper formation of collagen fibrils. Seeds of the sweet pea contain
beta-aminopropionitrile
that prevents the cross-linking of
collagen
by inhibiting
lysyl oxidase
and thus the formation of
allysine
, leading to loose skin. Recent experiments have attempted to develop this chemical as a treatment to avoid disfiguring skin contractions after skin grafting.
[10]
Genetics
[
edit
]
Gregor Mendel
is today recognized as the "Father of Modern Genetics" for his work with the cross breeding of
pea
plants (
Pisum sativum
) with different characteristics, and sweet pea has been used in a similar way. The sweet pea is thus a
model organism
being used in early experimentations in genetics, particularly by the pioneer geneticist
Reginald Punnett
. It is highly suitable as a genetic subject because of its ability to self-pollinate and its easily observed Mendelian traits such as colour, height and petal form. Many genetic principles were discovered or confirmed in this species. It was used by Punnett in early studies of
genetic linkage
.
[11]
Complementary factor inheritance was also elucidated in sweet peas, from the cross of two pure-breeding white strains which gave rise to a blue hybrid, the blue colour requiring two genes derived independently from the two white parents.
[12]
Hybridization with
Lathyrus belinensis
[
edit
]
Like the
blue rose
, the yellow sweet pea remains elusive.
Lathyrus belinensis
is a related Lathyrus species which has red and yellow flowers. There are ongoing attempts to bring the yellow color into
Lathyrus odoratus
by crossing it with
Lathyrus belinensis
. Several new sweet pea cultivars have been created as a result, though not any with the yellow flower color so far.
[13]
Gallery
[
edit
]
See also
[
edit
]
References
[
edit
]
- ^
Rowe, J., Shehadeh, A., Maxted, N., Donnini, D. & Branca, F. (2019).
"
Lathyrus odoratus
"
.
IUCN Red List of Threatened Species
.
2019
: e.T176367A61528477.
doi
:
10.2305/IUCN.UK.2019-2.RLTS.T176367A61528477.en
. Retrieved
17 January
2024
.
{{
cite journal
}}
: CS1 maint: multiple names: authors list (
link
)
- ^
Euro+Med Plantbase
- ^
Brickell, Christopher (1996).
Encyclopedia of Garden Plants
. London: Royal Horticultural Society.
ISBN
0-7513-0436-0
.
- ^
Rice, Graham (2002).
The Sweet Pea Book
. Batsford. p. 9.
- ^
RHS A-Z encyclopedia of garden plants
. United Kingdom: Dorling Kindersley. 2008. p. 1136.
ISBN
978-1405332965
.
- ^
Why Sweet Pea Leaves Turning Yellow
- ^
"How to grow sweet pea flowers [Easily]"
.
Shiny Plant
. 2021-01-02. Archived from
the original
on 2021-05-17
. Retrieved
2021-02-11
.
- ^
Dastur, D.K. and Iyer, C.G. (1959). Lathyrism versus odoratism.
Nutr. Rev.
17:33-6.
- ^
Dasler, W. (1954). Observations of odoratism (sweet pea lathyrism) in the rat. Journal of Nutrition 53: 105-13.
- ^
Sweet peas make a second skin
- Guardian, UK, July 2008
- ^
Punnett, R.C. (1923). Linkage in the sweet pea (
Lathyrus odoratus
).
Journal of Genetics
13: 101?123.
- ^
Bateson, W., Saunders, E.R. and Punnett, R.C. (1906). Experimental studies in the physiology of heredity.
Reports to the Evolution Committee, Royal Society of London
3.
- ^
Dawn Edwards.
Developing a yellow sweet pea