Variation in relative growth rate in the Chenopodium album aggregate in relation to ploidy level

Steven Musoni

Master's thesis

Abstract:

Genus Chenopodium is comprised of about 100-170 species which are distributed mainly in temperate zone. Some Chenopodium species are among the world’s worst weeds. However, some species are domesticated for food and source of medicine in different parts of the world.Most Chenopodium species are polyploids which is an important trait as far as evolution is concerned because when some species undergo polyploidization, it increases their adaptability in different habitats as their genome size is enlarged and can perform many functions that help the plant resisting in different habitats. The main purpose of this study was to compare relative growth rate among 8 Eurasian Chenopodium species from Greece, the Czech Republic and China with different ploidy levels (i.e. hexaploid, tetraploid and diploids). RGR experiment was carried out in a laboratory on 8 Eurasian Chenopodium species with different ploidy levels collected from different populations: C.acuminatum(2x), C.album (6x), C.ficifollium(2x), C.karoi(4x),C.novopokrovskyanum(4x), C.opulifollium(4x), C.stratiforme(4x) and C.strictum(4x). After 14 days of cold stratification, germinated Chenopodium species were introduced in a growing chamber and the regime was set as the ISP standard temperature was 22°C by day and 15°C by night, the ISP standard day had 14 hours and 10 hours day and night respectively. Humidity was set at 70%. Two destructive harvests were done in the third week and the fifth week in order to measure leaf area, leaf weight, stem weight and root weight. Finally, these parameters were used to measure RGR and its components. Specific leaf area (SLA), Net Assimilation Rate (NAR), Leaf Mass Ratio (LMR) and Leaf Area Ratio (LAR) were calculated using plant biomass from the first and second harvest. Surprisingly, there was no significant variation in RGR among Chenopodium species and among the ploidy levels. However, there was a significant variation in SLA, LAR and LMR among Chenopodium species. We also compared RGR in relation to plant invasiveness and phylogeny. However, there was no significant variation in RGR in relation to invasiveness and phylogeny.

Keywords

Chenopodium, Genome size, Ploidy level, Relative growth rate

Language used: English

Date on which the thesis was submitted / produced: 18. 4. 2018

Thesis defence

• Supervisor: prof. Mgr. Bohumil Mandák, Ph.D.

Czech University of Life Sciences Prague

Faculty of Environmental Sciences

Master programme / field:
Engineering Ecology / Nature Conservation