JOURNAL OF NANJING FORESTRY UNIVERSITY ›› 2022, Vol. 46 ›› Issue (5): 95-103.doi: 10.12302/j.issn.1000-2006.202105051

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Response of Cotinus coggygria photosynthesis and coloration to weather change in Chongqing

LI Linke1(), WANG Yinuo1, XUE Xiao1, ZHANG Wen1, WU Jiaojiao1, GAO Lan1, TAN Xing1, RONG Xingyu1, DUAN Rurong2, LIU Yun1,*()   

  1. 1. College of Resources and Environment, Southwest University, Chongqing 400715, China
    2. Chongqing Qianjiang Middle School, Chongqing 409000, China
  • Received:2021-05-30 Revised:2021-11-09 Online:2022-09-30 Published:2022-10-19
  • Contact: LIU Yun E-mail:401255794@qq.com;utrecht@swu.edu.cn

Abstract:

【Objective】The aim of this research is to study the effects of unusual continuous rainy weather on photosynthesis of Cotinus coggygria of Chongqing, and to investigate the responses in photosynthesis and color of the C. coggygria plant to weather changes so as to provide a scientific basis for artificial care of C. coggygria.【Method】 Local meteorological data in recent years were collected and analyzed to clarify the difference between the proportion of cloudy and rainy days, precipitation, sunshine duration, and the relative humidity in Chongqing in 2019 and those of recent years. In 2018, at the same time, N,P,K was used to examine the Cotinus coggygria leaf growth, photosynthesis, and the influence of color based on this research. In 2019 from April to November, monthly monitoring avoiding rainy days was undertaken as a control. This was undertaken under the conditions of natural root container planting for four years for Cotinus coggygria. The photosynthetic characteristics, the leaf blade pigment content, and the leaf color parameters were measured and compared with the data collected in 2018. The correlation between the meteorological factors, the photosynthetic characteristics, and the leaf color was analyzed.【Result】 In 2019, during the growing period for Cotinus coggygria from April to November, a rare rainy weather event was observed in Chongqing, and rainy weather was observed during more than half of the monitoring period. In 2019, compared with 2016-2018, the sunshine hours decreased by 10%-25%, the maximum daily precipitation increased by 30%-37%, the average rainfall increased by 12.5%-25.0%, and the average temperature decreased by 1%-2%. High humidity, high levels of rainfall, and an environment with low levels of sunshine is not conducive to Cotinus photosynthetic pigment synthesis. As a result, the net photosynthetic rate (Pn) decreased and the leaf color quality was found to be poor. The correlation analysis showed that Pn was significantly positively correlated with the sunshine duration (SD), temperature (Q) (P < 0.01), photosynthetically active radiation (PAR) (P < 0.05), and the daily precipitation ≥ 0.1 mm (DPD).The transpiration rate (Tr) was significantly positively correlated with SD and Q (P < 0.01), PAR (P < 0.05), DPD (P < 0.01), and the atmospheric carbon dioxide concentration (Ca) (P < 0.05). There was a significant positive correlation between the chlorophyll a (Chla) content and Q (P < 0.05). Anthocyanin content was negatively correlated with DPD (P < 0.5). The luminance (L*) was significantly positively correlated with chlorophyll b (Chlb) content (P < 0.01) and was significantly positively correlated with the Chla content (P < 0.05). The red/green hue (a*) was significantly negatively correlated with the contents of Chla and Chlb (P < 0.01). There was no significant correlation between the contents of other pigments and the leaf color parameters (P > 0.05). The a*was significantly negatively correlated with Tr, Pn and Gs (P < 0.01). The yellow/blue hue (b*) was significantly negatively correlated with Tr, Pn and Gs (P < 0.01). The chroma (C*) was significantly negatively correlated with Tr and Pn (P < 0.01) and the stomatal conductance(Gs) (P < 0.05).【Conclusion】 Results from the study showed that for Cotinus coggygria under continuous wet weather conditions, while the apparent quantum efficiency (AQY) is reduced, the Pn is reduced, the ability to photosynthesize under low light levels is weak, and the leaf color quality is poor. However, in terms of CO2, this taxon has a wide ecological amplitude and a wider tolerance range for illumination. By increasing the Chlb content, it improves their ability to use scattered light to adapt to poor weather conditions, supporting a strong tolerance to continuous rainy weather. These results can provide a reference for the introduction and cultivation of Cotinus coggygria and its scientific management in China.

Key words: Cotinus coggygria, pigment content, photosynthesis parameter, color quality, overcast and rainy, Chongqing

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