Physiological responses of Goji berry (Lycium barbarum L.) to saline-alkaline soil from Qinghai region, China

Zhenzhong Zhang,Da Tang,Kangning He,Runjie Li,Tan Zhang,Shaofeng Jia

doi:10.1038/s41598-019-48514-5

Abstract

Recently, Goji berry (Lycium barbarum L.) has been extensively cultivated to improve the fragile ecological environment and increase the income of residents in Qinghai Province, northwestern China. However, few studies have focused on the physiological responses of Goji berry under salt stress and alkali stress. Gas exchange, photosynthetic pigments, and chlorophyll fluorescence were evaluated in response to neutral (NaCl) and alkali (NaHCO3) salt stresses. Nine irrigation treatments were applied over 30 days and included 0(Control group), 50, 100, 200, and 300 mM NaCl and NaHCO3. The results showed that salt and alkali stress reduced all the indicators and that alkali stress was more harmful to Goji berry than salt stress under the same solution concentrations. The salt tolerance and alkali resistance thresholds were identified when the index value exceeded the 50% standard of the control group, and threshold values of 246.3 ± 2.9 mM and 108.4.7 ± 2.1 mM, respectively, were determined by regression analysis. These results were used to identify the optimal water content for Goji berry. The minimum soil water content to cultivate Goji berry should be 16.22% and 23.37% under mild and moderate salt stress soils, respectively, and 29.10% and 42.68% under mild and moderate alkali stress soil, respectively.

Highlights

Salt-alkalization is becoming an increasing environmental and socioeconomic problem because it leads to the loss of agricultural land at a rate of 0.25 to 0.5 Mha annually around the world[1]
The trend exhibited by Ci under alkali stress was similar to that exhibited under salt stress, the value started to increase at 200 mM (P < 0.05, Fig. 1D)
The values of these photosynthetic parameters likely indicate the adaptability of Goji berry, and the values are far lower under alkali stress than under salt stress, which suggests that Goji berry seedlings are less adaptable to alkali stress than salt stress

Summary

Introduction

Salt-alkalization is becoming an increasing environmental and socioeconomic problem because it leads to the loss of agricultural land at a rate of 0.25 to 0.5 Mha annually around the world[1]. Chlorophyll (Chl) fluorescence represents a sensitive and noninvasive probe and has been used to study the function and performance of the photosynthetic machinery of various plants, and several recent works have shown that this tool can be useful for identifying stress factors that affect or/and limit plant growth[22]. Goji berry has been proposed as a potential pioneer plant to reclaim salinized and alkalinized soils because Goji berry growth and photosynthesis have been shown to be negatively affected by high levels of salt stress[27].

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Discussion

Conclusion