Question

Does the initial uptake of water by seeds depend on temperature? One way to answer this question is to soak seeds in water at different temperatures and measure the rate of water uptake at each temperature. T temperature coefficient, o.the factor bry which a physiological process he collected data can be used to caloulate the or reaction rate increases when the temperature is raised by 10°C 六 where t higher temperature "C)t ower temperature, k reaction rate at t, and k reaction rate at t1 (Note that 4 a-f 10, as in this exercise the math is simplited ) o values may be used to make inlerences about the physiological process under investigation. Chemical (metabolic) processes dependent on temperature and have higher Qo values, closer to 2 or 3 In contrast, many, bul not all, physical parameter to 1. For example, the Qo of the change in the viscosity of water is 1.2-1.3. In this exercise, you will caiculate Qo using data uptake of water by seeds is more likely to be a physical or a chemical process invoiving large-scale peotein shape changes are nighty s are relatively independent of temperature and have Qm values closer for radish soeds (Raphanus sativus) to assess whether the intil Samples of radsh seeds were weighed and placed in water at our different tompera atures. After 30 minutos, the soods were removed, bliotted dry and reweighed. The researchers then calculated the percent increase in mass due to water uptake for each sample Their data are shown in the table % increase in Mass Due to Water Uptake after 30 Minutes 185% Temperature 5°С 15°C 25"C 35°C 260% 310% 36 2% Data from J. D Murphy and D. L. Noland Temperature eflects on seed mbibition and leakage mediated by viscosity and membranes, Plant Physiology 69 428-431 (1982)

Answer 1

Q₁₀ = (R₂/R₁)^{(10/T₂-T₁)}

Q₁₀ is the factor by which the reaction rate increases when the temperature is raised by ten degrees.

Q₁₀ is a unit less quantity.

R₁ is the measured reaction rate at temperature T₁ (where T₁ < T₂). Note that R₁ and R₂ must have the same unit.

R₂ is the measured reaction rate at temperature T₂ (where T₂ > T₁). Note that R₁ and R₂ must have the same unit.

T₁ is the temperature at which the reaction rate R₁ is measured (where T₁ < T₂). The temperature unit must be either the Celsius or the Kelvin, and may not be any other unit, such as the Fahrenheit. Note that T₁ and T₂ must have the same unit. T₁ and T₂ do not need to be exactly 10 degrees apart.

T₂ is the temperature at which the reaction rate R₂ is measured (where T₂ > T₁). The temperature unit must be either the Celsius or the Kelvin, and may not be any other unit, such as the Fahrenheit. Note that T₁ and T₂ must have the same unit. T₁ and T₂ do not need to be exactly 10 degrees apart.

Q₁₀ = (R₂/R₁)^{(10/T₂-T₁) = _{(26.0/ 18.5)} (10/15-5) ₌ 26.0/18.5 _{= 1.41}}

5 to 15 ºC = 1.41

^{_{(31.0/ 26.0)} (10/25-15) ₌ 31.0/26.0 _{= 1.19}}

15 to 25 ºC= 1.19

^{_{(36.2/ 31.0)} (10/35-25) ₌ 36.2/31.0 _{= 1.17}}

25 to 35 ºC = 1.17

Average = 1.41 + 1.19 + 1.17 / 3 = 1.26