Photosynthetic characteristics and the response of stomata to environmental determinants and ABA in Selaginella bryopteris, a resurrection spike moss species.
Selaginella bryopteris is a spike-moss lycophyte species with resurrection capability. These plants have small sized stomata that occur in higher density than in other fern species. The diurnal gas-exchange studies under natural conditions showed a bell shaped net photosynthesis curve. The effective quantum yield of PSII (ΔF/F(m')) showed an inverse relationship with light and recovered to its maximum at sunset. This suggests that there was a complete recovery of PSII efficiency during the late evening hours. S. bryopteris displayed broad temperature optima for net photosynthesis from 28 °C to 37 °C. The stomatal sensitivity in response to vapor pressure deficit (VPD), was maximum at 25 °C temperature while at temperatures from 30 to 35 °C it was low. Our study demonstrates that S. bryopteris plants show a very poor mechanism for its stomatal regulation in response to high light, high temperature, high VPD, high CO₂ and to ABA treatment. At the same time they show a high stomatal conductance leading to unrestricted rates of transpiration and a lack of capacity to optimize water use efficiency (WUE).
Plant Physiology Division, CSIR(1)-National Botanical Research Institute, Rana Pratap Marg, Lucknow 226001, India.
Devendra K
DK
Soni
Sanjay
S
Ranjan
Ruchi
R
Singh
Prem B
PB
Khare
Uday V
UV
Pathre
Pramod A
PA
Shirke
D000040:Abscisic Acid / Q000494:pharmacology*; D002245:Carbon Dioxide / Q000494:pharmacology; D002940:Circadian Rhythm / Q000187:drug effects; D004777:Environment; D005453:Fluorescence; D005740:Gases / Q000378:metabolism; D008027:Light; D010788:Photosynthesis / Q000187:drug effects* / Q000502:physiology / Q000528:radiation effects; D054046:Plant Stomata / Q000187:drug effects* / Q000502:physiology* / Q000528:radiation effects; D032503:Selaginellaceae / Q000187:drug effects* / Q000502:physiology* / Q000528:radiation effects; D013696:Temperature
D005740:Gases; D002245:Carbon Dioxide; D000040:Abscisic Acid