Identify two factors that may contribute to variations in ph

Identify two factors that may contribute to variations in photosynthetic rate for aquatic plants. How will i change in these factors affect photosynthetic rate? Compared to terrestrial plants, what challenges do aquatic plants have to overcome in order to carry out photosynthesis? Based on your answers to question 1 and the list of available materials for the Photosynthesis lab provided in the lab manual develop a hypothesis that you could test in lab for how a single environmental factor affects photosynthesis. Include a brief justification for your hypothesis.

Solution

Answers:

1. Factors which contribute to variations in photosynthetic rates in aquatic plants are:

(a) Temperature:

Photosynthetic rates at saturating light and DIC (Dissolved inorganic carbon)  increase with temperature due to stimulation of enzyme activity up to an optimum level depending on the adaptation and acclimation of the species but are usually located between 25 and 32°C for temperate submerged aquatic plants.

(b) Reduced leaf thickness:

Photosynthetic rates per unit dry mass increase significantly with reduced leaf thickness, higher relative surface area, and higher concentrations of pigments and nitrogen in structural and catalytic proteins, including Rubisco.

2. A comparison with terrestrial leaves characterizes the aquatic leaves by their lower chlorophyll and Rubisco concentrations and lower photosynthetic rates per surface area mainly due to the thin leaves of most aquatic species. This finding has been interpreted as a result of selection of submerged plants to match the low rates of carbon influx predominantly because of high transport resistance.

Thin submerged leaves with chloroplasts in epidermal layers will also increase the cost effectiveness of light use and can also be regarded as a particular advantage in a low light aquatic environment with no risk of desiccation damage to the epidermal layers.