常春藤对甲醛和弱光胁迫的解剖结构及生理特征响应

Anatomical structure and physiological characteristics of ivy with formaldehyde and weak light stress

以2种常春藤Hedera盆栽苗为试验材料,在密封的玻璃容器中,设置甲醛、弱光及甲醛+弱光3个胁迫处理和1个对照,处理4个月后,分别采样测定叶的解剖结构及根、叶的生理生化指标,探讨甲醛和弱光环境胁迫处理对2种常春藤解剖结构和生理特性及适应性的影响。结果表明:洋常春藤Hedera helix的栅栏组织厚度、气孔长度和气孔宽度在甲醛和弱光胁迫下均显著(P<0.05)减小,而甲醛胁迫使叶厚和海绵组织厚度增大,弱光下气孔密度增大;中华常春藤Hedera nepalensis的叶厚、栅栏组织厚度、海绵组织厚度、气孔长度、气孔宽度和气孔密度在各胁迫下均减小。各胁迫使2种常春藤的根系活力均显著(P<0.05)下降;在甲醛和弱光双重胁迫下,洋常春藤的甲醛质量分数高于中华常春藤;中华常春藤的叶绿素质量分数在甲醛胁迫下下降,而弱光下则上升,洋常春藤与之相反;双重胁迫使2种常春藤的叶绿素质量分数显著(P<0.05)下降,类胡萝卜素质量分数显著(P<0.05)上升。弱光下2种常春藤根系和叶片的超氧化物歧化酶(SOD)活性下降,而甲醛和双重胁迫使2种常春藤根系和叶片的超氧化物歧化酶活性及根系的过氧化物酶(POD)活性显著(P<0.05)下降。此外,各胁迫还使2种常春藤的过氧化氢和丙二醛质量摩尔浓度、相对电导率及氧自由基产生速率上升。可见,中华常春藤对弱光的适应性强于洋常春藤,而洋常春藤对甲醛的抗性强于中华常春藤。

To determine the effects of formaldehyde and weak light stress on anatomical and physiological characteristics of two species of ivy(Hedera helix and Hedera nepalensis) with their adaptability, potted seedlings were used as experimental materials. Sealed glass containers held three stress treatments of formaldehyde, weak light, and formaldehyde + weak light, and a control. After four months of treatment, the anatomical structure of leaves, the physiological and biochemical indexes of roots and leaves were measured. Results for H. helix showed that with formaldehyde and with weak light stress, palisade tissue thickness, length and width of stomata decreased significantly(P<0.05); whereas spongy tissue thickness increased with formaldehyde stress, and spongy tissue density increased with weak light. However, for H. nepalensis and stress, thickness of the leaf,palisade tissue, and spongy tissue; and the length, width, and density of stomata all decreased. For both ivies,root vigor with all stresses decreased significantly(P <0.05). With formaldehyde and formaldehyde + weak light stresses, formaldehyde content of H. helix was higher than H. nepalensis. Also, with formaldehyde stress,chlorophyll content in H. nepalensis decreased, but it increased with weak light which was contrary to H. helix.In addition, with the formaldehyde + weak light stress treatment, chlorophyll content in both ivies decreased significantly(P<0.05), but carotenoid content increased significantly(P<0.05). In both ivies with the weak light treatment, superoxide dismutase(SOD) activity of roots and leaves decreased, and with formaldehyde and double stress the SOD activity in roots and leaves along with peroxidase(POD) activity in roots decreased significantly(P<0.05). Finally, for both ivies with all stresses, hydrogen peroxide, malondialdehyde(MDA), relative electrical conductivity, and the oxygen free radical generation rate increased. Thus, the adaptability of H.nepalensis to weak light was stronger than H. helix, but the resistance to formaldehyde was contary.