Some of the conditions that affect the amount of sucrose and fructan in grass include intensity of sunlight, duration of sunlight, temperature, water availability, soil fertility, developmental and genetic characteristics of species of grass, and the overall health of the grass. Because grass uses photosynthesis to process energy, the WSC will accumulate if photosynthesis is delayed or irregular. During the dark hours, the plants use WSC stored from the daylight hours. The level of WSC would be expected to decrease as the night hours passed, with the lowest level present at dawn. Fructan and sucrose exist in a ratio in the normal grass plants in temperate regions.
Environmental stress causes the sucrose to be used up at a faster rate.
Furthermore, grass stores fructan in the lower portion, so when closely grazed grass regrows, fructans are the primary storage unit. Add in low temperatures, disease, etc., and the grass' rate of growth will be slowed, and fructans will be high. However, fructan is not the cause of stress in grass, but rather a secondary result of slowed growth. The Welsh researchers gave an example of a frosty morning. Bright sunlight would stimulate fructan production, but low temperatures would slow down growth, making the fructan accumulate.