水分胁迫对油茶苗生理生化特性的影响

Effects of drought stress on physiological and biochemical characteristics of Camellia oleifera seedlings

选择一年生油茶优株闽43嫁接苗为试验材料进行水分胁迫处理,在不同时期测得的土壤含水率作为不同处理组,研究其生理生化指标,并作出显著性水平分析。结果表明,叶绿素含量和POD活性表现出先上升后下降的趋势,在胁迫35 d时分别达到最大值2.16 mg·g^-1和4.91μg·g^-1·min^-1。丙二醛、游离脯氨酸含量和可溶性糖含量整体上表现出逐渐上升的趋势,并都在胁迫75 d时达到最大值,分别为11.64 mmol·g^-1、347.90μg·g^-1和0.261μg·g^-1。可溶性蛋白则表现出逐渐下降的趋势,在胁迫75 d时降至最低值4.77 mg·g^-1。综上所述,油茶苗在轻度胁迫时期（15-25 d）能够正常生长,中度胁迫时（25-45 d）出现抗逆机制,重度胁迫时（45-75 d）则发生枯萎直至死亡。持续干旱的油茶苗最好能够及时浇水,以免影响油茶的正常生长。

One-year-old grafted seedlings of Min-43, one of the excellent species in Fujian province were used in a drought stress test. Different soil moisture contents determined in different periods were used to analyze some physiological and biochemical characteristics of C. oleifera seedlings. The results were as follows. Under drought stress condition, chlorophyll content and POD activity in Camellia oleifera seedlings at first increased, then decreased. They reached the maximum values of 2.16 mg·g^-1 and 4.91 μg·g^-1·min^-1, respectively at the 35thdays after the drought stress. The content of MDA, free proline, and soluble sugar were increasing in general and reached the highest values of 11.64 mmol·g^-1, 347.90 μg·g^-1 and 0.261 μg·g^-1, respectively at the 75th days, while the soluble protein content was decreasing to the lowest value of 4.77 mg·g^-1at the 75th days. In conclusion, C. oleifera seedlings grew well under the mild drought stress for 15 to 25 days. Under the moderate drought stress for 25 to 45 days, the drought resistance in the plant was induced; under the severe drought stress for 45 to 75 days, the seedlings withered and eventually died. It is important that C. oleifera seedlings should be watered on time; otherwise their growth will be affected.