Leaf area meter

A split-plot layout with a randomized complete block design was used, to set up the experiment. The six colchicine concentrations were allocated to the main plots, whereas the four soaking durations (1, 2, 3, and 4 h) were arranged in the sub-plots. Each plot included three pots in each replicate, with a total of 720 pots. During harvest time, plant height, root length, and flower width were measured. Leaf number per plant was counted and leaf area was measured using a leaf area meter (LI-COR, Lincoln, NE, USA). The number of branches and flowers per plant were also counted. Leaf chlorophyll content was estimated using a Chlorophyll Content Meter CCM-200 (OPTI-SCINECE, Tyngsboro, Massachusetts, USA), which measures chlorophyll absorbance. This apparatus calculates values from the ratio of optical absorbance at 660 and 940 nm (Richardson et al., 2002) (link). Flowering date and the fresh and dry weights of flowers were determined. Fresh and dry shoot and root masses were also recorded. Data were collected in the M 1 -and M 2 -generations of the two successive experimental seasons.

The percentage of seed germination was recorded after 6 weeks from sowing. The calendula plants were grown until flower maturity when the plants were harvested. At the harvesting stage, the plant height and flower diameter were measured. The number of leaves per plant was counted, and leaf area was measured using a leaf area meter (LI-COR, Lincoln, NE, USA). The number of branches and flowers per plant were also calculated. The flowering date (days from sowing) in each treatment was determined, and the fresh shoot and dry weights were recorded. The shoot dry weight was determined by drying the shoots in an oven at 70°C for 48 h until the weight was constant. These data were collected for both M 1 -and M 2 -generations in two successive experimental seasons.