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低温胁迫对连翘幼苗叶片生理特性的影响

Effects of cold stress on leaf physiological characteristics in Forsythia suspensa (Thunb.) Vahl seedlings

  • 摘要: 连翘(Forsythia suspensa (Thunb.) Vahl)作为常见的早春花卉和大宗药用作物,低温是其在春季面临的主要胁迫因素。本研究以连翘幼苗叶片为试材,测定其在4个低温条件下的相对电导率、丙二醛(MDA)、脯氨酸(Pro)、可溶性糖(SS)、可溶性蛋白(SP)和叶绿素含量、超氧化物歧化酶(SOD)和过氧化物酶(POD)活性以及叶绿素荧光参数等指标的变化。结果显示,低温胁迫引起连翘叶片相对电导率和MDA含量升高。连翘叶片通过多种途径抵御低温伤害,SP、SS、SOD在胁迫前期发挥主要作用,胁迫增强时Pro和POD发挥更为主要的作用。JIP-test分析结果表明,低温对光合作用产生显著影响,主要体现在对电子传递的抑制和受体侧的伤害上,0℃处理伤害最为严重。低温胁迫影响连翘幼苗生长,4℃以上低温胁迫解除后,其生长可得到恢复,而0℃低温胁迫对其造成的伤害不可逆。

     

    Abstract: Forsythia suspensa (Thunb.) Vahl is a common early spring flower and bulk cultivated medicinal crop. Low temperature is the main stress factor for this species in spring. To date, however, no physiological research has explored the effects of low temperature on F. suspensa growth. Here, we used the leaves of F. suspensa seedlings and detected changes in relative conductivity, malondialdehyde (MDA), proline content (Pro), soluble sugar (SS), soluble protein (SP), chlorophyll content, superoxide dismutase (SOD), peroxidase (POD) activity, and chlorophyll fluorescence parameters under four temperature conditions. We also detected chlorophyll fluorescence parameters after recovery. Results showed that low temperature stress caused an increase in relative electrical conductivity and MDA content in the leaves, which affected growth to some extent. The resistance of F. suspensa leaves to low temperature was achieved by multiple pathways. SP, SS, and SOD played major roles at the early stage of cold stress, while Pro and POD played important roles when stress intensity increased. The JIP-test showed that low temperature had a significant effect on photosynthesis, mainly reflected in the inhibition of electron transfer and damage to the receptor side. Treatment damage at 0℃ was the most serious. Low temperature stress affected the growth of F. suspensa seedlings. Low temperature stress above 4℃ affected the seedlings, but growth recovered after the stress was removed. Damage caused by low temperature stress at 0℃ was irreversible. Thus, F. suspensa should be cultivated in areas where low temperatures are less common in late spring, or cold-tolerant varieties should be selected for cultivation in areas where low temperatures are more frequent in late spring.

     

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