干旱条件下叶片非顺序衰老小麦顶二叶叶绿素荧光特性

Chlorophyll fluorescence characteristics of top two leaves in non-sequencial senescence wheat under drought condition

以非顺序衰老小麦温麦19、兰考矮早8和豫麦19为材料,以顺序衰老小麦陕229为对照,研究了田间干旱和自然天气条件下小麦扬花至成熟期旗叶和倒二叶叶绿素荧光特性的变化规律。结果表明,无论在田间干旱还是自然天气条件下,扬花至成熟期非顺序衰老小麦温麦19、兰考矮早8和豫麦19,顺序衰老小麦陕229旗叶和倒二叶叶绿素含量(SPAD)、PSII实际光化学效率(ΦPSII)、最大光化学效率(Fv/Fm)、PSII潜在活性(Fv/Fo)均呈下降趋势,而热耗散量子比率(Fo/Fm)呈上升趋势。在花后30天非顺序衰老和顺序衰老现象差异最明显,在干旱条件下,花后30天非顺序衰老小麦温麦19、兰考矮早8和豫麦19旗叶的SPAD、ΦPSII、Fv/Fm和Fv/Fo分别比倒二叶低71.86%、30.43%和40.81%,29.59%、14.84%和20.43%,28.99%、33.33%和31.66%,32.08%、30.4%和52.16%,而Fo/Fm旗叶分别比倒二叶高13.78%、24.56%和35.93%;在自然天气条件下,花后30天非顺序衰老小麦温麦19、兰考矮早8和豫麦19旗叶的SPAD、ΦPSII、Fv/Fm和Fv/Fo分别比倒二叶低44.36%、25.49%和41.75%,21.97%、12.48%和13.74%,24.77%、26.12%和30.86%,27.02%、26.22%和32.81%,而Fo/Fm旗叶分别比倒二叶高11.31%、23.07%和33.95%。顺序衰老小麦陕229的表现正好与此相反。与自然天气条件相比,在干旱条件下叶片的衰老明显加快,旗叶和倒二叶叶绿素荧光特性差异更大,叶片非顺序和顺序衰老现象表现更明显。

Chlorophyll fluorescence characteristics of flag leaf and the second leaf in sequential senescence wheat Shaan 229 and non-sequential senescence wheat Wenmai 19, Lankaoaizao8 and Yumail9 were measured after flowering under drought and natural conditions. Chlorophyll content, ΦPSII, Fv/Fm, Fv/Fo of flag leaf and the second leaf in reverse order of the tested wheat varieties from flowering to mature were decreased, but Fo/Fm was increased under drought condition and natural condition. The difference of sequential senescence and non-sequential senescence was obvious at 30 d after flowering. In drought condition, chlorophyll content, ΦPSII, Fv/Fm, Fv/Fo of flag leaf of non-sequential senescence wheat Wemnai 19, Lankaoaizao8 and Yumail9 were respectively lower than the second leaf. By contrast, Fo/Fm of flag was higher than the second leaf. In natural c, ondition, chlorophyll content, ΦPSII, Fv/Fm, Fv/ Fo of flag leaf of non-sequential senescence wheat Wenmai 19, Lankaoaizao8 and Yumail9 were respectively lower than the second leaf. However, Fo/Fm of flag was higher than the second leaf. The chlorophyll fluorescence characteristics of flag leaf and the second leaf in sequential senescence wheat Shaan 229 was opposite from the non-sequential senescence wheat. In drought condition, leaf senescence was noticeably accelerated, the difference of chlorophyll fluorescence characteristics of flag leaf and the second leaf was larger, and the phenomenon of sequential senescence and non-sequential senescence were observable.