ABSTRACT

A comparative study of some biochemical parameters and expression patterns during flower development and senescence in Nicotiana plumbaginifolia and Petunia hybrida was carried out to ascertain the differences between the two important ornamentals. Lipid peroxidation (LPO) was found to increase throughout flower development and senescence in P. hybrida whereas in N. plumbaginifolia it decreased towards flower opening and showed a sharp increase towards senescence. Membrane stability index showed a marginal decrease towards senescence in the flowers of both the plants. Activities of the antioxidant enzymes (superoxide dismutase, catalase, ascorbate peroxidase, and lipoxygenase) increased up to the open flower stage (stage IV) and decreased thereafter towards the senescent stage in the flowers from both the plant species. The pre-senescent stages in flowers from both the plants did not show up the detection of ethylene in the petal tissues on gas chromatograph while as a climacteric rise in the ethylene concentration was exhibited by the senescent stages of both the flowers under study. mRNA-transcripts of senescence associated gene DAD1 were found to accumulate in the open flower stage (stage IV) in N. plumbaginifolia and those of ETR1 and SAG12 were found to accumulate in the open flower stage (stage IV) in P. hybrida.

摘要

对白花烟草和矮牵牛花发育和衰老过程中的一些生化参数和表达模式进行了比较研究，以确定两种重要观赏植物之间的差异。在P. hybrida 中发现脂质过氧化 (LPO) 在整个花发育和衰老过程中增加，而在N. plumbaginifolia它在开花时减少，并在衰老时急剧增加。膜稳定性指数显示两种植物的花朵衰老均略有下降。两种植物的抗氧化酶（超氧化物歧化酶、过氧化氢酶、抗坏血酸过氧化物酶和脂肪氧化酶）的活性在开放花阶段（IV 阶段）之前增加，然后在花的衰老阶段降低。两种植物的花的衰老前阶段在气相色谱仪上都没有显示在花瓣组织中检测到乙烯，而在研究中的两种花的衰老阶段都表现出乙烯浓度的更年期上升。衰老相关基因DAD1 的mRNA 转录本被发现积聚在开放的花阶段（阶段IV）中N. plumbaginifolia和那些的ETR1和SAG12发现积聚在开放的花阶段（阶段IV）在矮牵牛。