Effects of Different Shading Rates on the Photosynthesis and Corm Weight of Konjac Plant

Yaoguo QIN; Zesheng YAN; Honghui GU; Zhengxiang WANG; Xiong JIANG; Zhizhou CHEN; Fuqing YANG; Cuiqin YANG

doi:10.15835/nbha47311437

Authors

Yaoguo QIN Sichuan Agricultural University, College of Horticulture, Chengdu 611130 (CN)
Zesheng YAN Sichuan Agricultural University, College of Horticulture, Chengdu 611130 (CN)
Honghui GU Sichuan Agricultural University, College of Horticulture, Chengdu 611130 (CN)
Zhengxiang WANG Sichuan Agricultural University, College of Horticulture, Chengdu 611130 (CN)
Xiong JIANG Sichuan Agricultural University, College of Horticulture, Chengdu 611130 (CN)
Zhizhou CHEN Sichuan Agricultural University, College of Horticulture, Chengdu 611130 (CN)
Fuqing YANG Sichuan Agricultural University, College of Horticulture, Chengdu 611130 (CN)
Cuiqin YANG Sichuan Agricultural University, College of Agriculture, Chengdu 611130 (CN)

DOI:

https://doi.org/10.15835/nbha47311437

Keywords:

chlorophyll fluorescence parameter; konjac; photosynthesis; shading

Abstract

To study the effects of shading level on the photosynthesis and corm weight of konjac plant, the chlorophyll fluorescence parameters, daily variation of relative electron transport rate (rETR), net photosynthetic rate (Pn), and corm weight of konjac plants under different treatments were measured and comparatively analyzed through covered cultivation of biennial seed corms with shade nets at different shading rates (0%, 50%, 70%, and 90%). The results showed that with the increase in shading rate, the maximum photochemical efficiency, potential activity, and non-photochemical quenching of photosystem Ⅱ (PSⅡ) of konjac leaves constantly increased, whereas the actual photosynthetic efficiency, rETR, and photochemical quenching of PSⅡ initially increased and then decreased. This result indicated that moderate shading could enhance the photosynthetic efficiency of konjac leaves. The daily variation of rETR in konjac plants under unshaded treatment showed a bimodal curve, whereas that under shaded treatment displayed a unimodal curve. The rETR of plants with 50% treatment and 70% treatment was gradually higher than that under unshaded treatment around noon. The moderate shading could increase the Pn of konjac leaves. The stomatal conductance and transpiration rate of the leaves under shaded treatment were significantly higher than those of the leaves under unshaded treatment. Shading could promote the growth of plants and increase corm weight. The comprehensive comparison shows that the konjac plants had strong photosynthetic capacity and high yield when the shading rate was 50%-70% for the area.

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