Research On Evaluation Of Plant Salt Tolerance Based On Infrared Thermal Imaging Technology

In order to make up for the shortcomings of traditional screening and evaluation methods for salt-tolerant plants,such as various methods,cumbersome and complicated operations,and irreversible damage to plants,etc,Na Cl solution was used to conduct a 45-day stress experiment on Populus×euramericana‘Neva’,Elaeagnus angustifolia L.,Nitraria sibirica and Tamarix chinensis Lour.("Qiaocheng No.1")in this study.After the salt stress,the growth morphology,leaves temperature and other indicators are measured.First,using conventional evaluation methods to evaluate the order of plant salt tolerance.Then through the control tested of emissivity and shooting distance,the factors affecting infrared thermal imaging technology are explored.Use the most suitable shooting distance and emissivity to obtain thermal images of plant leaves under different salt concentrations.Establish the response equation of leaves temperature under salt stress,and based on infrared thermal imaging technology to rank the salt tolerance of plants.Finally,the conclusions drawn from the two approaches are compared and verified.Explore the creation of a simple,accurate,and non-damaging new approach for the evaluation of plant salt tolerance.This study has reached the following conclusions:(1)The membership function method was used to evaluate the salt tolerance of 10conventional indicators under Na Cl stress,and the order of salt tolerance of the 4 testeded plants was obtained:Tamarix chinensis Lour.>Nitraria sibirica>Elaeagnus angustifolia L.>Populus×euramericana‘Neva’.This results is the same as the sequence of plant salt tolerance based on the symptoms of salt damage.(2)The experiment also explored the influence of different emissivity and shooting distance on leaves temperature.It is found that the emissivity of 0.96 and the vertical shooting distance of 30 cm can obtain accurate and relatively stable temperature data.(3)Based on infrared thermal imaging technology,the order of the salt tolerance of the four tested plants at low salt concentration(less than 200m M)from high to low is Elaeagnus angustifolia L.,Tamarix chinensis Lour.,Nitraria sibirica and Populus×euramericana‘Neva’.When the salt concentration is greater than 200m M,the salt tolerance order is Tamarix chinensis Lour.>Nitraria sibirica>Elaeagnus angustifolia L.It is also speculated that under the same salt concentration,the leaves temperature of plants with strong salt tolerance will be relatively low.(4)The leaves temperature and stomatal conductance of tested plants(except for Tamarix chinensis Lour.)showed a very significant negative correlation(p<0.01),which proved that under salt stress,stomatal is still the dominant factor affecting plant leaves temperature.Secondly,leaves temperature is also positively correlated with different degrees of Na~+content and Cl~-content in leaves.Other indicators such as biomass,K~+content,and K~+/Na~+value have a weak correlation with leaves temperature.