GeoChemBio.com/biology/organisms/Lactuca sativa (lettuce)

 

Lettuce flower
Lettuce seeds

Please help keeping these websites open for everybody as long as possible

 

Lactuca sativa, lettuce

Download this page in pdf format (can be old)
Print

Back to top
Nemose

cellular organisms - Eukaryota - Viridiplantae - Streptophyta - Streptophytina - Embryophyta - Tracheophyta - Euphyllophyta - Spermatophyta - Magnoliophyta - eudicotyledons - core eudicotyledons - asterids - campanulids - Asterales - Asteraceae - Cichorioideae - Cichorieae - Lactuca - Lactuca sativa

Back to top
Nemose

Brief facts

Morphological types of L. sativa (Lebeda et al. (2007))

  1. Butterhead lettuce: loose head with soft and tender leaves, eaten raw; very popular in Europe and USA.
  2. Crisphead lettuce: heading type with thick crisp leaves and fan-like (flabellate) leaf venation, eaten raw.
  3. Cos lettuce (named after Greek island Cos): tall loose heads; oblong rigid leaves with a prominent midrib; eaten raw or cooked. Often, Cos lettuce cultivars are sold as "Romaine lettuce".
  4. Cutting lettuce (Gathering lettuce, Loose-leaf, Picking lettuce, Schnittsalad): non-heading type, harvested as whole, as open rosettes, and, occasionally as separate leaves; eaten raw. Cultivars vary widely in leave shape and coloration - from flat to curled, from smooth-edged to fringed, from plain green to decoratated with patterns of various intensities of anthocyanin pigmentation.
  5. Stalk (Asparagus) lettuce: plants with swollen stalks, which are eaten raw or cooked like asparagus; very popular in China and India.
  6. Latin lettuce: loose heads with dark green thick leathery leaves; eaten raw; mainly cultivated in the Mediterranean countries, including North Africa.
  7. Oilseed lettuce: characterized by a high percentage (35%) of oil in the seeds, which is used for cooking; in Egypt, cultivation of oil-seed lettuce has continued to the present time.

Most important lettuce diseases

Back to top
Nemose

Developmental stages (life cycle)

Back to top
Nemose

Back to top
Nemose

Lettuce seeds were sowed on April 25th, 2010.

Young lettuce plant, 40 days after sowing. Lettuce began to bolt in about 2 months after sowing.
40 days old young lettuce plant 2 months old starting to  bolt  lettuce
Two different lettuce cultivars continue bolting 2.5 months after sowing.
2.5-months old bolting lettuce plant 2.5-months old bolting lettuce plant
Young inflorescence with flower buds 3 months after sowing. Lettuce plant flowering. Flowers open gradually as the inflorescence grows.
3 months old lettuce with flower-buds 3.5 months old flowering lettuce plant

Back to top
Nemose

Lettuce growing at George Washington's Mount Vernon garden

Lettuce at George Washington's Mount Vernon garden

 
 

Back to top
Nemose

 
 

Popular lettuce, fresh produce

 
 

Back to top
Nemose

Appendix I: lettuce die-back disease

Simko I, Pechenick DA, McHale LK, Truco MJ, Ochoa OE, Michelmore RW, Scheffler BE.
Association mapping and marker-assisted selection of the lettuce dieback resistance gene Tvr1. BMC Plant Biol. 2009 Nov 23;9:135.

Lettuce dieback disease is widespread in commercially grown romaine and leaf-type lettuces. The disease is caused by two closely related soilborne viruses from the family Tombusviridae - Tomato bushy stunt virus (TBSV) and Lettuce necrotic stunt virus (LNSV). Symptoms of lettuce dieback include mottling and necrosis of older leaves, stunting, and plant death.

Lettuce die-back disease

Dieback symptoms on different types of lettuce:
A - stem type, B - leaf type, C - green romaine, and D - red romaine.
Plants on the left are healthy, while plants on the right show typical symptoms of dieback, such as stunted growth, yellowing of older leaves, and gradual dying. Photographs were taken eight weeks after planting.

Back to top
Nemose

References

Websites

Back to top
Nemose