A researcher investigated the growth of 6 specices of floodplain plants. Each species was classified as either flood-sensitive (S) or flood-tolerant (T) (see Table 1).
Experiment
Seeds from each of the 6 species were germinated in a growth chamber maintained at 25.5°C during the day and at 10°C at night.
After germination, the seedlings of each species were planted in separate 0.5 L pots and grown for 4 weeks. The seedlings were watered 3 times per week.
At the end of the 4 weeks, each plant was repotted into its own 4 L pot containing a substrate composed of a 4: 1 mixture, by mass, of sand to compost. The plants were grown for 2 more weeks; during this time, they were watered 3 times per week.
Next, the potted plants were placed in plastic tubs such that each tub contained 8 plants of each species. Each tub of plants was subjected to a different treatment (see Table 2) for 3 weeks.
At the end of the 3-week treatments, the plants were harvested, and their roots were washed. The roots were separated from the shoots, and then both were dried at 70°C for 48 hr. The average dry shoot biomass per plant and the average dry root biomass per plant were determined for each species and treatment combination (see Figures 1 and 2, respectively).
19. When the water level was maintained 2 cm above the substrate surface, which floodplain plants, the T species plants or the S species plants, had the greater average dry root biomass per plant?
Answer and Explanation
Your Answer is
Correct Answer is A
Explanation
The condition given in the question stem is 2 cm above the surface, so we can see from table 2 that we should pay attention to Treatment 3;
Because the question stem asks about root biomass, so see figure 2, It is found that the root biomass of Rp is the largest;
Compared with table 1, the classification of Rp is T, which is flood-tolerant
