Latitudinal variation in tuber production in an aquatic pseudo-annual plant, Potamogeton pectinatus
In: Aquatic Botany. Elsevier Science: Tokyo; Oxford; New York; London; Amsterdam. ISSN 0304-3770; e-ISSN 1879-1522, more
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| Keywords |
Anatomical structures > Body organs > Plant organs
Anatomical structures > Body organs > Plant organs > Plant reproductive structures
Flora > Aquatic organisms > Aquatic plants
Reproduction > Asexual reproduction
Spatial variations > Latitudinal variations
Hydrilla verticillata (L. f.) Royle [WoRMS]; Potamogeton pectinatus L. [WoRMS]
Fresh water |
| Author keywords |
day lengths; latitude; asexual reproductions; short-day response;critical size |
| Authors | | Top |
- Santamaría, L.
- Llano García, A.I.
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| Abstract |
The effect of day length and latitude on the induction of tuberisation in Potamogeton pectinatus L. was investigated. Six clones originally collected at widely different latitudes (from 24°N in Egypt to 68°N in Russia) were used to test two hypotheses: (1) tuberisation is a short-day response, and (2) critical day length increases with increasing latitude. Plants sprouted from tubers of a standardised size (50-150 mg fresh weight) were allowed to grow for 56 days under long-day conditions (22 h light) and then transferred for 21 days to eight different day lengths (12, 13, 14, 15, 16, 18, 20 and 22 h light). While the frequency of tuberising plants was not significantly affected by day length, it increased from 2 to 87% with increasing latitude of origin. Other plant traits such as size at induction, biomass yield and biomass allocation were correlated with tuberisation frequency. However, none of them accounted for the correlation between tuberisation frequency and latitude. A comparable analysis on Hydrilla verticillata, using Steward's [Hydrobiologia 354 (1997) 571] data, showed that the induction and abundance of tuber and turion production increased with increasing latitude (N=23, range 3-40°, N and S latitudes pooled) and with decreasing day length (10 h versus 16 h). The effect of day length did not account for the positive correlation between tuber and turion production and the clone's latitude of origin of the clones. We thus conclude that there is a latitudinal trend towards an earlier onset of asexual reproduction in these two pseudo-annual plant species, which is not caused by variation in their response to day length. |
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