Leaf Chlorophyll Fluorescence and Gas Exchange Response to Different Light Levels in &lt;i&gt;Platycerium bifurcatum&lt;i/&gt;

Sanusi Sanusi

doi:10.3844/ajabssp.2011.214.220

Abstract

Problem statement: Platycerium bifurcatum (Cav.) C. Chr . is epiphytes which lives in forest canopy and commonly used for its ornamental value. In these en vironments, they were always exposed to many types of stresses such as high ligh t intensity. Light intensity plays an important rol e in affecting plant's physiological performance. Theref ore, the purpose of this study was to investigate physiological responses of P. bifurcatum to light stress. Approach: In this study, P. bifurcatum were grown under four different Photosynthetic Active Ra diation (PAR) levels which were 20 µmol m -2 s -1 (T1), 70 µmol m -2 s -1 (T2), 200 µmol m -2 s -1 (T3) and 1500 µmol m -2 s -1 (T4). Leaf gas exchange and chlorophyll fluorescence were used to evaluate the stress response of various levels of light intensit y. All measurements were carried out on weekly basis for twelve weeks. Results: Results showed that Anet value of T1, T2 and T3 in the range near to the av erage A ne t value for most epiphytes. Conversely, T4 showed lower value in A net with 1.797 µmol CO 2 m -2 s -1 . Fv/Fm ratio in T3 and T4 were below 0.8 indicates that there was a sign of stress occurred in these treatments. However A net of T3 was not affected although there have been event of photoinh ibition observed in the treatment. On the contrary, T4 was fully affected by high light intensity as th ere was a reduction of Fv/Fm ratio and also Anet . T1 and T2 of A net and Fv/Fm ratio values ranged of unstressed plants after subjected to light treatmen t. Conclusion: Measurement of leaf chlorophyll fluorescence and g as exchange are useful to detection of light stress in P. bifurcatum . Different levels of light intensity were signific antly affecting physiological attributes of P. bifurcatum .

Highlights

Forest is a place rich of diversity for many life functions and operated as a habitat for many types of flora and fauna
With many types of living population live in and under the canopy, there have been several complexity of the structure and microclimate occurs within crown of a tree such as in climate change is concerned, for plant that lives under plant canopy such as epiphytes, they are usually exposed to elements of harsh environment and experienced the climate fluctuation
Sci., 6 (2): 214-220, 2011 and Kropp, 2011). In this type of habitat and the atmosphere below tree canopy, many types of environmental stress are likely to occur to this type of plant especially stress of high light intensity

Summary

Introduction

Forest is a place rich of diversity for many life functions and operated as a habitat for many types of flora and fauna. Forest canopy plays role as one of the important features of a tree since it performs as a shade and for shelter for other living rather than trunks Nadkarni et al (2004). Through this complexity, canopy plants do relatively response in terms of both function and its structure. Sci., 6 (2): 214-220, 2011 and Kropp, 2011) In this type of habitat and the atmosphere below tree canopy, many types of environmental stress are likely to occur to this type of plant especially stress of high light intensity.

Objectives

Methods

Results