Seasonal variation of photosynthesis and photosynthetic efficiency in Phalaenopsis

Abstract

Nowadays, a quest for efficient greenhouse heating strategies, and its related effects on the plant’s performance, exists. In this study, the effects of a combination of warm days and cool nights in autumn and spring on the photosynthetic activity and efficiency of Phalaenopsis were evaluated; the latter, being poorly characterised in CAM plants and, to our knowledge, not reported before in Phalaenopsis. 24-h CO2 flux measurements and chlorophyll fluorescence analysis were performed in both seasons on Phalaenopsis ‘Hercules’ exposed to relatively constant temperature regimes, 25.5/24.0°C (autumn) and 30/27°C (spring) respectively, and distinctive warm day/cool night temperature regimes, 27/20°C (autumn) and 36/24°C (spring), respectively. Cumulated leaf net CO2 uptake of the distinctive warm day/cool night temperature regimes declined with 10-16% as compared to the more constant temperature regimes, while the efficiency of carbon fixation revealed no substantial differences in both seasons. Nevertheless, a distinctive warm day/cool night temperature regime seemed to induce photorespiration. Although photorespiration is expected not to occur in CAM, the suppression of the leaf net CO2 exchange during Phase II and Phase IV as well as the slightly lower efficiency of carbon fixation for the distinctive warm day/cool night temperature regimes confirms the involvement of photorespiration in CAM. A seasonal effect was reflected in the leaf net CO2 exchange rate with considerably higher rates in spring. In addition, sufficiently high PAR levels in spring led to an efficiency of carbon fixation of 1.06-1.27% which is about twice as high than in autumn. As a result, only in the case where a net energy reduction between the temperature regimes compensates for the reduction in net CO2 uptake, warm day/cool night temperature regimes may be recommended as a practical sustainable alternative

CAM‐physiology and carbon gain of the orchid Phalaenopsis in response to light intensity, light integral and CO2

“…Because of the variety of regions and habitats for CAM‐plants (desert, mountains and epiphytic growth in tropical forests), there are strong differences in the physiological adaptation to environmental cues and the extent to which species engage in CAM relative to C 3 (Winter, Holtum, & Smith, 2015). Responses of Phalaenopsis to light and CO 2 have been studied in mostly horticultural studies (e.g., Guo, Lin, & Lee, 2012; Lootens & Heursel, 1998; Pollet, Steppe, Dambre, Van Labeke, & Lemeur, 2010). Both diel CO 2 uptake, as well as leaf initiation rate, increased when light intensities increased (Hückstädt & Torre, 2013; Ota, Morioka, & Yamamoto, 1991).…”

Studying Optical Characteristics of Diffused Light Reflecting from Naturally Senescing Leaves of Deciduous Trees

“…Seasonal changes in the color of tree leaves depend on such external factors as decrease in the sunny day duration, total daily temperature and level of solar radiation [1]. Color of tree leaves also directly depends on the internal biochemical processes that are connected to regulation of the nutrient substances' resorption from leaf cells often under conditions of biotic and abiotic stress [2][3][4][5][6]. This leads to leaf senescing within the phenological cycle, which results in chloroplasts senescing and turning them into chromoplasts.…”

Protein Distribution and Stalk Localization Following Temperature Variation in the Growth and Spiking Period of Phalaenopsis

“…The growth and blooming process of Phalaenopsis species is regulated and controlled by environmental factors in nature. [1][2][3] Understanding this temperature-controlled process is of great economic importance for many nations such as the Netherlands, Tailand, and Taiwan. Frequently, blooming in Phalaenopsis requires a growth period of 8-16 weeks before the spiking induction process.…”

“…Frequently, blooming in Phalaenopsis requires a growth period of 8-16 weeks before the spiking induction process. 2 For the spiking process, Phalaenopsis prefers a temperature-controlled environment maintained at approximately 20-25°C for 1-2 months. 4,5 Nutrition is also known to be critical to blooming quality in Phalaenopsis species, 6,7 and the measurement of total protein, certain reducing sugars, and total carbohydrate is commonly used to monitor growth.…”

“…14,15 Indeed, temperature variation is a key to the successful blooming of the orchid naturally. 2,16 In this report, we analyzed protein variations in orchid leaves to elucidate the relationship between temperature variation and the spiking process. In the nutrition period, we found that protein distribution is similar in each leaf of the same orchid specimen and the majority of protein activity is related to the photosystems.…”