Juvenile Leaf Color Changes and Physiological Characteristics of Acer tutcheri (Aceraceae) during the Spring Season

Leaf color is a key trait that determines the ornamental quality of landscape tree species such as Acer tutcheri, and anthocyanin is the main pigment for red leaf coloration. Red leaf fading significantly reduces the ornamental value of A. tutcheri leaves in the spring; however, the physiological mechanism that causes red leaf discoloration in this species is still unclear. Only the anabolic or degradative metabolism of anthocyanin has been studied in terms of leaf color changes. In this study, leaves from four color-change stages of A. tutcheri during the spring were selected by the average sampling method, which involves measuring and analyzing the pigment content and physiological factors related to anthocyanin metabolism, aiming to clarify the key physiological factors of spring leaf coloration. Our results show that the reduced anthocyanin/chlorophyll ratio was the direct cause of red leaf fading in spring. The carbohydrates synthesized during the growth of juvenile leaves were mainly used for their growth and development, whereas fewer carbon sources were used for the synthesis of anthocyanin. Phenylalanine ammonia-lyase and chalcone isomerase activities increased in the early stages of juvenile leaf development and decreased in the middle and late stages, whereas peroxidase activity continued to increase. The decrease in anthocyanin synthesis-related enzyme activity reduced the accumulation of anthocyanin, whereas the increase in anthocyanin degradation-related enzyme activity accelerated the depletion of anthocyanin. Increasing vacuole pH was a major factor in the degradation of anthocyanin. The physiological characteristics of A. tutcheri leaves during the spring season suggest that anthocyanin is a key factor affecting the presentation of color in juvenile leaves, and red leaf fading in the spring of A. tutcheri is the result of the joint effect of the decrease in anthocyanin anabolic metabolism and the increase in anthocyanin degradative metabolism

Growth Rhythm Analysis of Young Stand and Selection of Superior Families in <i>Choerospondias axillaris</i>

As an important source of medicine, food, and high-quality wood, Choerospondias axillaris has been widely planted in South China. However, few studies of its growth traits and rhythm and concerning the selection of superior provenances/families were developed. In this study, 77 families from five provenances were studied and grouped. Tree height, diameter at breast height (DBH), and crown width within and between rows were measured. The relevance between growth traits and environmental factors was also analyzed. The results showed the height, DBH, and crown width within and between rows were divided into slow, mean, and fast growth periods, which was significantly related with sunshine hours in earlier months. Next, monthly rainfall showed an extremely positive correlation with the increase in tree height, DBH, and plant volume. Then, the monthly volume increment had a significantly positive correlation with five meteorological factors, excluding sunshine hours with increasing months, while the monthly growth of tree height and crown width within and between rows was significantly negatively correlated with sunshine hours. Based on these results, the superior families No. 15, 76, and 56, which originated from the Raoping provenance, were selected for their fast growth and available adaptation. These results provided the reliable growth rhythm of a young C. axillaris stand, which established a basis for fertilizing and forest tending. During these processes, meteorological factors, especially humidity and sunshine duration, had important effects on growth, implying that the external climate should be paid more attention to promote fast growth and prevent diseases and insect pests. Moreover, selecting superior families was helpful to further breeding and plantation

Growth Rhythm Analysis of Young Stand and Selection of Superior Families in Choerospondias axillaris

As an important source of medicine, food, and high-quality wood, Choerospondias axillaris has been widely planted in South China. However, few studies of its growth traits and rhythm and concerning the selection of superior provenances/families were developed. In this study, 77 families from five provenances were studied and grouped. Tree height, diameter at breast height (DBH), and crown width within and between rows were measured. The relevance between growth traits and environmental factors was also analyzed. The results showed the height, DBH, and crown width within and between rows were divided into slow, mean, and fast growth periods, which was significantly related with sunshine hours in earlier months. Next, monthly rainfall showed an extremely positive correlation with the increase in tree height, DBH, and plant volume. Then, the monthly volume increment had a significantly positive correlation with five meteorological factors, excluding sunshine hours with increasing months, while the monthly growth of tree height and crown width within and between rows was significantly negatively correlated with sunshine hours. Based on these results, the superior families No. 15, 76, and 56, which originated from the Raoping provenance, were selected for their fast growth and available adaptation. These results provided the reliable growth rhythm of a young C. axillaris stand, which established a basis for fertilizing and forest tending. During these processes, meteorological factors, especially humidity and sunshine duration, had important effects on growth, implying that the external climate should be paid more attention to promote fast growth and prevent diseases and insect pests. Moreover, selecting superior families was helpful to further breeding and plantation

Finite Element Analysis and Experimental Study of Metal Shell of GIL

Mathematical modeling, finite element numerical simulation and experimental measurement of the stress-deformation distribution of the gas-insulated metal-enclosed transmission line shell were carried out. Also, Stress linearization analysis was used to analyze the maximum stress. The results show that the stress is linearly dependent on water pressure and the shell occurs elastic deformation without plastic deformation. The simulated maximum stress of 76.2MPa is fairly in good agreement with the measured one (69.9MPa). The stress linearization analysis results show that the shell well satisfies the environmental safety requirements. The experimental results are consistent with the finite element results