The Changes of Leaf Reflectance Spectrum and Leaf Functional Traits of Osmanthus fragrans Are Related to the Parasitism of Cuscuta japonica

Abstract

Studies on the influence of parasitism on plants based on hyperspectral analysis have not been reported so far. To fully understand the variation characteristics and laws of leaf reflectance spectrum and functional traits after the urban plant parasitized by Cuscuta japonica Choisy. Osmanthus fragrans (Thunb.) Lour. was taken as the research object to analyze the spectral reflectance and functional traits characteristics at different parasitical stages. Results showed that the spectral reflectance was higher than those being parasitized in the visible and near-infrared range. The spectral reflectance in 750~1400 nm was the sensitive range of spectral response of host plant to parasitic infection, which is universal at different parasitic stages. We established a chlorophyll inversion model (y = −65913.323x + 9.783, R2 = 0.6888) based on the reflectance of red valley, which can be used for chlorophyll content of the parasitic Osmanthus fragrans. There was a significant correlation between spectral parameters and chlorophyll content index. Through the change of spectral parameters, we can predict the chlorophyll content of Osmanthus fragrans under different parasitic degrees. After being parasitized, the leaf functional traits of host plant were generally characterized by large leaf thickness, small leaf area, small specific leaf area, low relative chlorophyll content, high leaf dry matter content and high leaf tissue density. These findings indicate that the host plant have adopted a certain trade-off strategy to maintain their growth in the invasion environment of parasitic plants. Therefore, we suspect that the leaf economics spectrum may also exist in the parasitic environment, and there was a general trend toward the “slow investment-return” type in the global leaf economics spectrum.

Physiological responses and variation in secondary metabolite content among Thai holy basil cultivars (Ocimum tenuiflorum L.) grown under controlled environmental conditions in a plant factory

“…Variation in reflection spectral characteristics were observed. Moreover, different spectral characteristics of leaf materials is generally maintained in the same plant species at different growth stage conditions (Xie et al, 2013;Misǔrec et al, 2016;Zhu et al, 2021). The characteristic responses of the light spectrum reflected in those plants could be estimated by the health status, plant productivity, and plant quality by calculating the ratio of light reflectance characteristics caused by pigment absorption (Gitelson et al, 2005;Buschmann et al, 2012;Kim et al, 2018).…”

Assessment of benefits resulting from the use of computer control systems in precision agriculture

“…Spectral analysis of the spectrum of light reflected from the plant surface allows us/the user to determine their condition [9]. The parameter that proves the condition of plants is the proportion of the light reflectance in the range of visible light to the infrared band (Fig.…”