Morphological and photosynthetic response to high and low irradiance of Aeschynanthus longicaulis.

Qiansheng Li,Min Deng,Allen Coombes,Wei Zhao,Yanshi Xiong

doi:10.1155/2014/347461

Abstract

Aeschynanthus longicaulis plants are understory plants in the forest, adapting to low light conditions in their native habitats. To observe the effects of the high irradiance on growth and physiology, plants were grown under two different light levels, PPFD 650 μmol·m–2 ·s–1 and 150 μmol·m–2 ·s–1 for 6 months. Plants under high irradiance had significantly thicker leaves with smaller leaf area, length, width, and perimeter compared to the plants grown under low irradiance. Under high irradiance, the leaf color turned yellowish and the total chlorophyll decreased from 5.081 mg·dm−2 to 3.367 mg·dm−2. The anthocyanin content of high irradiance leaves was double that of those under low irradiance. The plants under high irradiance had significantly lower Amax (5.69 μmol·m–2 ·s–1) and LSP (367 μmol·m–2 ·s–1) and higher LCP (21.9 μmol·m–2 ·s–1). The chlorophyll fluorescence parameter F v/F m was significantly lower and NPQ was significantly higher in high irradiance plants. RLCs showed significantly lower ETRmax⁡ and E k in plants under high irradiance. It can be concluded that the maximum PPFD of 650 μmol·m–2 ·s–1 led to significant light stress and photoinhibition of A. longicaulis.

Highlights

Aeschynanthus Jack (Gesneriaceae) comprises approximately 160 species distributed from Sri Lanka and India through southern China and Southeast Asia to New Guinea and the Solomon Islands
The leaves grown under high irradiance were typically narrower with a thicker appearance as compared to the leaves under low irradiance
Leaves under high irradiance had a significantly smaller leaf area, length, width, and perimeter length compared to the thinner leaves of plants grown under low irradiance

Summary

Introduction

Aeschynanthus Jack (Gesneriaceae) comprises approximately 160 species distributed from Sri Lanka and India through southern China and Southeast Asia to New Guinea and the Solomon Islands. Aeschynanthus plants are noted for their brilliant red, orange, or yellow tubular flowers that often appear in large terminal clusters. The plants are usually epiphytic, shrubby, climbing, or trailing in habit, with dark green or mottled waxy leaves. They can be grown in a hanging pot or basket at home or outdoors. Don. There are some cultivars which are popular in horticulture, for example, Aeschynanthus “Bali,” “Red Cascade,” “Hot Flash,” “Rigel,” and “Big Apple,” with different flower colors [2]. It is estimated that more than 50 species and/or cultivars are marketed for ornamental purposes. Aeschynanthus plants are among the most popular hanging basket and potted flowering plants in the floriculture industry [3]

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