Solanum tuberosum, potato

Download this page in pdf format (can be old)

Back to top

cellular organisms - Eukaryota - Viridiplantae - Streptophyta - Streptophytina - Embryophyta - Tracheophyta - Euphyllophyta - Spermatophyta - Magnoliophyta - eudicotyledons - core eudicotyledons - asterids - lamiids - Solanales - Solanaceae - Solanoideae - Solaneae - Solanum - Solanum tuberosum

Brief facts

• The potato is a herbaceous plant of the Solanaceae, or nightshade family, which contains several other well known cultivated crops such as tomato, eggplant, tobacco and pepper.
• The cultivated Solanum tuberosum subsp. tuberosum is considered to be originated from Andean and Chilean landraces developed by pre-Colombian cultivators. The wild species progenitors of these landraces probably derived from a group of ~20 similar wild species referred to as S. brevicaule complex, distributed from central Peru to northern Argentina.
• Potato is the only major tuber crop that is grown in temperate regions. It is also most important tuber crop in terms of production, accounting for about 45% of the total world production of all tuber crops (five species together account for almost 90% of total world production - potato, cassava, sweet potato, yams, and taro).
• Glycoprotein patatin constitutes about 20% of the total soluble protein in potato. The patatin exhibit enzymatic activity and is believed to play a role in defense against pests and pathogens. It also may elicit allergic responses in humans.
• Potato fruits, stems and leaves contain glycoalkaloids, toxic compounds, of which the most prevalent are solanine and chaconine.
• Potato's infamous pathogen is an oomycetes Phytophthora infestans (late blight, potato blight). Find out about Phytophthora infestans species' life cycle, tissues, mating types, and bibliography at MetaPathogen.

Back to top

Developmental stages (life cycle)

Life Cycle Stages

The potato plant has a short life span ranging from 80 to 150 days from planting to maturity, with differences existing between varieties. Its developmental stages are often described in terms of tuberization and tuber development. The life cycle of a potato tuber is characterized by initiation and growth followed by a period of dormancy and finally sprouting resulting in the next (vegetative) generation.

• Sprouting tuber Growth stage 1. The onset of sprout growth that follows dormancy termination is accompanied by substantial increases in cell metabolism; sprouts appear from the eyes of the primary tuber.
• Vegetative Growth stage 2. Plant establishment. All vegetative parts of the plants (leaves, branches, roots and stolons) are formed; stages 1 and 2 last from 30 to 70 days depending on planting date, soil temperature and other environmental factors, the physiological age of the tubers, and the characteristics of particular cultivars.
• Tuber initiation Growth stage 3. Approximately 30-60 days after the seed tuber is planted, tuber formation begins. Ttubers are derived from lateral underground buds developing at the base of the main stem that when kept underground develop into stolons due to diagravitropical growth. When the conditions are favorable for tuber initiation, the elongation of the stolon stops, and cells located in the pith and the cortex of the apical region of the stolon first enlarge and then later divide longitudinally. The combination of these processes results in the swelling of the subapical part of the stolon.
• Developing tuber Growth stage 4. During enlargement tubers become the largest sink of the potato plant storing massive amounts of carbohydrates (mainly starch) and also significant amounts of protein. Furthermore, tubers decrease their general metabolic activity and as such behave as typical storage sinks.
• Mature tuber Growth stage 5. Potato tubers are harvested from 90 to 160 days after planting and this may vary with cultivars, production area, and marketing conditions. Starch the typically represents 20% of the fresh weight of mature tuber. After potato vines die back the skin of tuber thickens and hardens, which provides greater protection to tubers during harvest and blocks entry of pathogens to the tuber.
• Dormant tuber Although dormancy is defined as the absence of visible growth, dormant meristems are metabolically active. In general, rates of many cellular processes such as respiration, transcription, and translation are suppressed during dormancy. Non-dividing, dormant tuber meristems are arrested in the G-1 phase.

Back to top

Potato tuber anatomy illustrated

 

Back to top

Potato tuber

• Tuber MeSHthe potato tuber is an enlarged portion of an underground In contrast to the widespread misconception, potato tubers do not develop from roots but are, in fact, underground stems.
  • Tuber eye The buds from which next season's growth will emerge. Eyes are concentrated near the apical end of the tuber, with fewer near the stolon or basal end. Eye number and distribution are characteristic of the variety
  • Tuber skin Tuber skin is composed of two layers of cells: an outer layer of single cells called the epidermis, underlain by several layers of corky cells called the periderm. The periderm layer may contain a pigment that produces coloured potatoes.
  • Tuber cortex Tissue between skin and a vascular ring.
  • Vascular ring Vascular ring contains cells that transport nutrients from the above ground stems to the medulla.
  • Tuber medulla Medulla represents the primary storage area for the potato tuber.
  • Tuber perimedulla Is located between the vascular ring and medulla.
• Stolon A slender horizontal stem of a plant that grows near the surface of the ground; it can sprout buds that can become new plants. Potato tubers grow at the end. of stolons

Back to top

 

References

• Spooner DM et al. A single domestication for potato based on multilocus amplified fragment length polymorphism genotyping. Proc Natl Acad Sci U S A. 2005 Oct 11.
• Ronning CM et al. Comparative analyses of potato expressed sequence tag libraries. Plant Physiol. 2003 Feb; 131(2):419-29.
• Fernie AR, Willmitzer L. Molecular and biochemical triggers of potato tuber development. Plant Physiol. 2001 Dec; 127(4):1459-65.
• Shewry PR. Tuber storage proteins. Ann Bot. 2003 Jun;91(7):755-69.

 

Websites

• Solanum tuberosum L.
• Potato Growth and Development
• Botany of the Potato Plant
• Potato Association of America Hanbook

Back to top

Appendix

Fischer L, Lipavska H, Hausman JF, Opatrny Z. Morphological and molecular characterization of a spontaneously tuberizing potato mutant: an insight into the regulatory mechanisms of tuber induction. BMC Plant Biol. 2008 Nov 21;8:117.

Morphology of Lada and ST plants. (A) Four-week-old plants grown in vitro under standard culture conditions (3% sucrose); (B) Sprouting of tubers stored for six months at 4°C; (C) Arrangement of tubers on three-month-old plants cultivated in pots under 15/9 (L/D) photoperiod; (D) Phenotype of four-week-old plants grown from tubers in pots under continuous light; (E) Detailed view on tuberization of ST plant grown under continuous light; note swelling buds, which are going to form sessile tubers; (F) Single-node cuttings of ST plants cultured in vitro on media with variable levels of sucrose (5% or 7% suc) under high (HL) or low (LL) irradiance (PPFD of 400–500 or 50–60 μmol m-2 s-1, respectively); cuttings are arranged from the most basal segment on the left to the apical one on the right; (G) Tuberization of single-node cuttings cultured on the tuberization medium in darkness for five weeks; (H) Three-week-old plants grown in the light on the medium supplemented with 5% sucrose and 3 mg/l GA₃.

The ST mutant was selected on the basis of its extraordinary phenotype – frequent spontaneous tuberization of single-node cuttings under non-inducing conditions, which were routinely used for the maintenance of shoot cultures in vitro.

Back to top