Stem water content (StWC = volume of water : volume of stem) is an important physiological parameter for vascular plants. And a better understanding of StWC contributes to solving some research hotspots in forestry, such as drought resistance, cold resistance, precise irrigation, and health assessment. However, there are few noninvasive, in situ, real-time, safe, and low-cost methods for detecting StWC of woody plants. This article presents a novel sensor for noninvasive detection of in situ StWC based on standing wave ratio. Moreover, extensive experiments were conducted to analyze the performance of this sensor including sensitive distance, measuring range, influence factors, and measuring accuracy. The experimental results show that the sensitive distance of StWC sensor is approximately 53 mm in axial direction and 20 mm in radial direction with the measuring range from 0.01 to 1.00 cm3 cm-3. The combined effects of stem EC and temperature on sensor output are significant and it is necessary to correct the error caused by the two factors. Compared with the oven-drying method, StWC sensor has higher measuring accuracy than Testo 606-2 which is a sensor for measuring wood water content and its average error is less than 0.01 cm3 cm-3. In addition, StWC sensor performed very well on the crape myrtle with high sensitivity equal to 1022.1 mV (cm3 cm-3)-1 and measuring results also accorded with the diurnal dynamics of stem water content.

To achieve a rational allocation of limited water resources, and formulation of an appropriate irrigation system, this research studied the change characteristics of stem water content (StWC) in plant and its response to environmental factors. In this study, the StWC and environmental factors of Lagerstroemia indica in Beijing were continuously observed by a BD-IV plant stem water content sensor and a forest microclimate monitoring station from 2017 to 2018. The variation of StWC and its correlation with environmental factors were analyzed. The results showed that the StWC of Lagerstroemia indica varies regularly day and night during the growth cycle. Meanwhile, the rising time, valley time, and falling time of StWC were various at the different growth stages of Lagerstroemia indica. The results of correlation analysis between StWC and environmental factors indicated that the StWC of Lagerstroemia indica was positively correlated with air relative humidity, while it was negatively correlated with total radiation and air temperature. The multiple regression equation of StWC and environmental factors of Lagerstroemia indica was StWC=11.789−1.402Rn−0.931T−1.132Ws+0.933RH−3.368ST+2.168SMC, and the coefficient of determination of the equation was of 0.87. Furthermore, the results illustrated that the irrigation should pay attention to supplementing irrigation in time during the peak growing season of fruit.

As times go by, people’s standard of living is constantly improving, but the medical pressure exerted by children with cerebral palsy is also increasing and the recovery of lower limb function in children with cerebral palsy after treatment has also gets people’s attention. Of course, the relevant medical equipment is constantly improving, especially the appearance of virtual reality technology, which has played an extremely important role in restoring the lower extremities of children with cerebral palsy. In order to study the role that virtual reality technology can play in children with cerebral palsy, this article collects relevant information, builds a case template, and uses comprehensive quantification by investigating patients, examining relevant documents, and interviewing professionals. With qualitative analysis, a damage assessment matrix is created. Experimental results prove that the use of virtual reality technology can improve the treatment efficiency of children with cerebral palsy by more than 30%. In terms of the rehabilitation effect of children’s lower limb function, virtual reality technology is more targeted for the treatment of children with far-reaching effects. It is much higher than traditional treatment methods, and the mobility of the children’s lower limbs is restored by more than 80%. This shows that virtual reality technology can play an important role in the rehabilitation of the lower limbs of children with cerebral palsy.