Overlapping Leaves Covering Flowers in the Alpine Species Eriophyton wallichii (Lamiaceae): Key Driving Factors and Their Potential Impact on Pollination.[Pubmed: 27716786]

Extrafloral structures are supposed to have evolved to protect flowers from harsh physical environments but might have effects on pollination. Overlapping leaves cover flowers in Eriophyton wallichii, an alpine perennial endemic to the Himalaya-Hengduan Mountains. In previous study, it has showed that these extrafloral leaves can protect interior flowers from temperature fluctuations caused by drastic solar radiation fluctuations, but these leaves may also protect interior flowers from rain wash and UVB damage, and we do not know which one is the main function. In this study, we investigated whether rain and UVB protection are the main functions of overlapping leaves covering flowers and their potential impact on pollination. We first measured the intensities of UVB radiation in open air, beneath leaves and corollas, and then examined pollen susceptibility to different intensities of UVB and rain in the laboratory to estimate whether corollas per se protect interior pollen from UVB and rain damage. We also carried out pollination treatments and observed pollinator visitation of flowers with and without leaves in the field to assess whether the overlapping leaves covering flowers impair pollinator attraction. Our results showed that (1) water and strong UVB significantly decreased pollen germinability, but corollas per se could protect pollen from UVB and rain damage; (2) no autonomous self-pollination and apomixis occurred, and pollinators were essential for the reproduction of E. wallichii; however, flower coverage by overlapping leaves did not limit pollination. We suggested that rain and UVB protection was not the main function of overlapping leaves covered flowers, given that this protection can be provided by corollas per se. Alternatively, this extrafloral structure in E. wallichii may have evolved in response to extreme high temperatures associated with the strong solar radiation fluctuations. This indicates that, even in alpine plants, extreme high temperature may affect the evolution of plant extrafloral structures.

Iridoid glycosides and glycosidic constituents from Eriophyton wallichii Benth.[Pubmed: 21601897]

C₉-iridoid glycosides, wallichiisides A-C, and four dimers, wallichiisides D-G, together with 13 known glycosidic compounds, were isolated from whole plants of Eriophyton wallichii Benth. Their structures were elucidated by spectroscopic methods and comparison with literature values. Four of these compounds showed moderate DPPH free radical scavenging activity.

[Studies on phenylpropanoids from herbs of Eriophyton wallichii].[Pubmed: 19216160]

To study the chemical constituents of Eriophyton wallichii.

[Studies on chemical constituents of Eriophyton wallichii].[Pubmed: 17639985]

To study the chemical constituents of Eriophyton wallichii.