Effect of Different Seedling Age on the Growth and Yield of Double Cropping of Late Rice

The study aims to solve the problems of late transplanting rice with differ- ent seedling ages at the lower reaches of Yangtze River. We selected six varieties of different thermal and photo-response characteristics as the test material to study the effect of different seedling ages on growth and yield of rice. The results showed that growing period of thermal-response rice was delayed by long seedling age, but less affected by the impact of photo-response rice; the yield of later thermal-re- sponse varieties with 25 days and 30 days seedling ages was significantly reduced. In contrast, the yield of early thermal-response varieties and later photo-response varieties were significantly reduced with 30 days seedling age. The optimal trans- planting seedling age was 15 days of thermal-response rice, while photo-response rice was 20 days. The thermal-response rice should be selected as early maturing varieties, while the photo-response rice could be selected as late maturing varieties for high yield.

A PRELIMINARY STUDY ON THE PHENOLOGY OF TAXUS CUSPIDATA SIEB.ET ZUCC.

In this paper, the phenomena of the life cycle of Taxus cuspidata Sieb. et Zucc., such as germination, leafing, flowing seed mature,new shoot growth etc. were observed and measured. As a result, the phenological regularity of Taxus cuspidata was found initially. At the same time,according to its five-day mean increment and height growth curve, the growing process of new shoot of Taxus cupidata was divided into three periods:slow period peak period and decline period. The paper supplied scientific data for the introduction of the rare and imininent variety, domestication,cultivating, expoiting, utilizing and protecting of Taxus cuspdata.

A Preliminary Study on the Infrared Spectra Characteristics of Radix Chuanmingshinis Violacei

[Objectives] To carry out infrared spectroscopic study of different growth years and different parts of the traditional Chinese medicine Radix Chuanmingshinis Violacei. [Methods]Using potassium bromide squash method and Fourier transform infrared spectroscopy on the different growth years and different parts of Radix Chuanmingshinis Violacei for infrared spectrum and second derivative spectrum. [Results]With the increasing growth time,Radix Chuanmingshinis Violacei accumulated in the secondary metabolism substances gradually increased,the characteristic absorption peak appeared in the position such as 3 366,2 927,1 634,1 416,1 516,1 080,1 020,and 928 cm^(-1),the main chemicals as polysaccharide,coumarin,saponins and steroids. The difference of chemical position between root tuber and cauline leaf is obvious. [Conclusions]Infrared spectroscopy was applied in studying different growing periods and different parts of Radix Chuanmingshinis Violacei,of obvious characteristics,identification and quality evaluation method,is simple and suitable for Radix Chuanmingshinis Violacei.

Temporal variation of resource allocation between sexual and asexual structures in response to nutrient and water stress in a floating-leaved plant

Aims Adaptive plasticity of biomass allocation to different environmental stressors enables plants to maintain functional relationships among reproductive structures.In freshwater systems,water depth and nutrient content of sediments can have a major effect on biomass allocation in aquatic macrophytes.However,the relative importance of these two stressors is unknown as it is the temporal variation of biomass allocation to the stressors during the growing period.This information may be critical for understanding the tolerance of a plant to environmental conditions.Methods Here,we used four levels of environmental stressors generated by deep and shallow water and high or low sediment nutrient content in a factorial experiment to investigate the biomass allocation responses of a floating macrophyte,Trapella sinensis,during the growing period.Important Findings The results showed that the lower sediment nutrient content inhibited biomass increase,whereas the lower water depth increased the sexual reproduction of the plants.The lower sediment content also led to a delay in flowering and compensated trade-offs among sexual reproduction and elongation and clonal reproduction during the growing period.These results indicated that water depth affected the ratio of biomass allocation,whereas the sediment nutrient content affected biomass accumulation when the plants faced these two environmental factors simultaneously.The temporal changes in allocation under lower sediment nutrient content underscored the importance of collecting data at different stages of growth when trying to interpret resource allocation,especially in resource-limited environments.