Physiological characteristics of Indonesian medicinal plants under varying photosynthetically active radiation (PAR): Toward adaptive strategies under environmental change
Titi Juhaeti1*, Mutiara K. Pitaloka1, Fitri Fatma Wardani1,3, Kartika Ning Tyas1, Inggit Puji Astuti1, Ria Cahyaningsih2, Iin Pertiwi A. Husaini1, Syamsul Hidayat2, Alifah Nur Hayati3, and Siti Vanessa Aisyah4
1Research Center for Applied Botany, National Research and Innovation Agency (BRIN), Jl. Raya Jakarta Bogor km 46 Cibinong, West Java, Indonesia 16911
2Research Center for Biota Systems, National Research and Innovation Agency (BRIN), Jl. Raya Jakarta Bogor km 46 Cibinong, West Java, Indonesia 16911
3Department of Agronomy and Horticulture, Faculty of Agriculture, IPB University, Jl Meranti Kampus IPB Dramaga, Bogor, Indonesia 16680
4Faculty of Mathematics and Natural Sciences, Padang State University, Kota Padang, Indonesia
Received:04 June 2025/ Revised:26 September 2025/ Accepted:11 October 2025/ Published Online: 23 October 2025
Abstract
Physiological traits such as photosynthetic rate (A), stomatal conductance (gsw), and intrinsic water-use efficiency (iWUE) are influenced by photosynthetically active radiation (PAR); however, their specific effects on individual plant species remain insufficiently studied. The objective of this study was to evaluate A, gsw, and iWUE in young and mature leaves under varying PAR levels (400, 1000, and 1600 µmol m⁻² s⁻¹) across six Indonesian medicinal plants: Dalbergia latifolia (DL), Murraya koenigii (MK), Murraya paniculata (MP), Syzygium cumini (SC), Syzygium polyanthum (SP), and Swietenia mahagoni (SM), to better understand their light-intensity tolerance for cultivation purposes. Data analysis revealed that A was significantly affected by species, leaf age, and PAR, whereas gsw and iWUE were influenced only by species and PAR (α = 0.01). The results highlight the broad adaptability of M. koenigii, which may perform well across a wide range of light conditions. In contrast, S. cumini, D. latifolia, and S. mahagoni appear to be more shade-tolerant, while M. paniculata and S. polyanthum seem better adapted to high-light environments, potentially favoring drier habitats due to their elevated iWUE under intense light. Collectively, these findings provide valuable insights to guide sustainable cultivation and conservation strategies for Indonesia’s medicinal plant resources.
Keywords: Intrinsic water use efficiency, Leaf age, PAR, Photosynthesis, Stomatal conductance
