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In order to determine an easy leaf age(LA)diagnostic method of panicle differentiation stage of sorghum, the panicle differentiation of sorghum and the relationship between differentiation stage and LA and leaf age index(LAI)were investigated. Hybrid cultivar ‘Jinyunuo 3' and conventional cultivar ‘Guojiaohong 1' were used as materials planted in three sowing dates, the panicle differentiation stage and corresponding LA were recorded. The results were as follows:(1)The panicle differentiation could be divided into five stages, i. e. vegetative stage, elongation stage, panicle branch differentiation stage, spikelet and floret differentiation stage, gynoecium and stamen formation stage. The sterile spikelet with stalk could develop to gynoecium and stamen formation stage.(2)With the detention of sowing date, the starting date of panicle differentiation was advanced, and the growth duration shorted, and LA and LAI of each stage of panicle differentiation were decreased, but there were differences among varieties.(3)The relationship between the panicle differentiation stage and LAI conformed to linear regression correlation, with a formula of panicle differentiation stage(Yi)to LAI(Xi) of Yi=bXi+a.(4)With the detention of sowing date, the parameter b and |a| in formula of ‘Jinyunuo 3' were increased, while those of ‘Guojiaohong 1' were decreased. To sum up, it is viable to infer panicle differentiation stage applying LAI, and the results provide theoretical basis for sorghum cultivation index management. [ABSTRACT FROM AUTHOR]

Loropetalum subcordatum(Hamamelidaceae)is one of rare and endangered species, and endemic species to China. The population structure is an element issue for its protection. The innovation of this paper was to analyzed population characteristics of L. subcordatum in Maolan Karst Natural Reserve, Guizhou Province and to provide countermeasure for protecting L. subcordatum. We investigated the population diameter structure, static life table and studied survival curve of L. subcordatum based on the survey. The results showed were as follows:(1)Proportion of the individual number of L. subcordatum was diameter Class Ⅳ(2.5 cm≤DBH<5 cm), which accounted for 27.0%, and the seedling bank accounted for 24.7%. Therefore, the population was stable with lots of seedling and young trees pool.(2)Diameter class Ⅱ(h>1.3 m, DBH<1 cm)and Class I(h<1.3 m)has the highest life expectancy. At Class V(5 cm≤DBH<7.5 cm), there was an inflection point of life expectancy. In Class I, Class Ⅱ, Class Ⅲ and Class IV, the life expectancy of L. subcordatum decreased with the age increasing. In Class VI, Class Ⅶ, Class Ⅷ and Class IX, the life expectancy of L. subcordatum was increased firstly and then decreased with the age increasing.(3)Class V had the highest mortality and disappeared rate, because of the environmental sieve especially water stress. The trend of mortality curve was consistent with disappeared rate curve and the curve was up and then slightly down with aging.(4)The survival curve was monotone decreased except for Class Ⅱ to Class Ⅲ(1 cm≤DBH<2.5 cm).(5)To protect the species more effectively, the best way is in-situ conservation(on-site maintenance). The medium diameter class of L. subcordatum needs more attention to tending. The L. subcordatum population in Maolan can have a better recovery potential, as long as continue to maintain the reforestation politics. [ABSTRACT FROM AUTHOR]