Effects of constant and fluctuating water temperature on growth and physiological and biochemical components of Halymenia sinesis

Abstract:

We studied the effects of different water temperature (17, 21, 25, 29, 33 ℃) and the fluctuating temperature (25±0, 25±2, 25±3, 25±4, 25±5 ℃) on the growth,pigment,POD,SOD and MDA of Halymenia sinesis. The results show:(1) the suitable temperature for H. sinesis growth was 17-29 ℃ with 25 ℃ and (±2, ±3 ℃) temperature fluctuation as the optimum growth temperature. When the temperature was above 29 ℃, the H. sinesis become soft and light color; above 33 ℃, the H. sinesis rotted locally.(2) The POD, SOD and MDA were stable when the temperature was below 25 ℃ and above 17 ℃.But they increased soon at 29 ℃or rise at first and decline from the fifth day at 33 ℃,which indicates that the H. sinesis suffered serious stress, so its cells damaged and decayed.(3) Compared with 25 ℃, the POD, SOD and MDA changes are stable in (±2, ±3 ℃) temperature range, and (25±3 ℃)﹥(25±2 ℃)﹥25 ℃.In addition, the change is severe in (±4, ±5 ℃) temperature range, and(25±5 ℃)﹥(25±4 ℃). To sum up, the H. sinesis can adapt to small temperature fluctuation. The greater the temperature difference, the greater the damage to H. sinesis.