Growth Rhythm Analysis on Annual Planting Seedlings of Pinus yunnanensis from Different Provenances

The ground diameter and the seeding height of Pinus yunnanensis from seven provenances of main distribution area were observed in the nursery of Southwest Forestry University. The growing rhythm of annual seedling from different provenances was analyzed by fitting the growth process of seedlings from different provenances with the Logistic equation. The result showed that the growing of the ground diameter and the seedling height both presented the rhythm in slowfastslow, which accorded with the “S” growing curve and represented the high accuracy of fitting. The growth processes of the ground diameter and the seedling height of annual seedlings were divided into the prophase of growing, the fastgrowing phase and the growing anaphase based on the phenological parameter gained from fitted equation. Ground diameter and seedling height in different growing phases of starting, ending and the continuance were varied. The ground diameter and the seedling height existed the phenomenon of differentspeed growing, the growth of seedling height started the fastgrowing phase earlier than that of the ground diameter. The ground diameter, growth continuance and daily growth in the prophase of growing, the fastgrowing phase and the growing anaphase were 82-111 days, 81-108 days and 6-62 days, 0003-0008mm, 0011-0027mm and 0004-0017mm, respectively, the seedling height were 33-61 days, 60-86 days, 80-133 days, 0115-0197mm, 0231-0475mm, 044-0163mm, respectively. The fastgrowing phase was short, but the proportion of increment was the largest. The ground diameter and fastgrowing phase accounted for 1/3 of the annual growing phase, and the increment accounted for more than 57% of the annual growth. The daily growth of the ground diameter during the fastgrowing phase was 13-36 times of that in other phases. The daily growth of the seedling height during the fastgrowing phase was 20-61 times of that in other two phases. According to the measurement, the growth of the ground diameter and the seedling height fitted the growing and theoretical growing extreme value k. The related coefficients were 07031 and 09989, respectively. The increment of the ground diameter and seedling growth in the fastgrowing phase was highly related with the Logisic linear regression. The related coefficient was 09999 and 09999, respectively. The result showed that the growth in different provenances of Pinus yunnanensis accorded with the “S” growing curve, and it has scientific significance in seedling cultivation of Pinus yunnanensis under the direction of the Logistic equation.