翠竹实生苗生长发育规律及构件生物量模型拟合研究

【目的】以小型地被类观赏竹种翠竹(Pleioblastus pygmaeus)为主要研究对象,进行翠竹1.5年生实生苗生长发育规律和构件生物量模型拟合的研究,为小型竹苗快速繁育和竹资源集中经营提供理论依据。【方法】翠竹播种后约1.5 a内的生长过程中,对其母株株高、地径,分蘖苗出苗时间及其株高、地径及竹鞭出现和发育等情况进行跟踪调查。采用Logistic 模型和多项式函数对翠竹1.5年生实生苗多个形态学指标(包括叶片干质量、茎秆干质量、分蘖苗株高、竹鞭长度等)进行数学模型拟合,剖析其重要构件生物量随时间的关系,株高、地径与生物量之间的关系以及生物量积累比例之间的关系等。【结果】翠竹在播种后约1周出土,第11天第1片叶全展开,约3个月出现第1代分蘖苗,约6个月一级竹鞭开始分化,1年后一级竹鞭系统上竹秆高生长旺盛,1.5 a后二级、三级竹鞭开始分化生长。随着分蘖苗的分化,其地径和株高也逐渐增加。翠竹实生苗多个构件生物量随时间的关系表现为增长趋势。翠竹实生苗的地径相同时,随苗高生长变大,其茎秆干质量增加。播种后3个月内,翠竹实生苗地上部分干质量大于地下部分干质量,地上、地下干质量比值呈现上升趋势;播种后3~7个月,翠竹实生苗地上部分干质量小于地下部分干质量,比值呈现上升趋势;播种10~12个月,翠竹实生苗地上部分干质量大于地下部分干质量,比值呈现先上升后下降趋势;播种1年后,翠竹实生苗地上部分干质量大于地下部分干质量,比值仍呈下降趋势,但逐渐趋于稳定。【结论】本研究揭示了翠竹从播种至高生长期间的生长发育规律及其重要构件的生长发育动态过程。翠竹实生苗高生长过程中重要构件生物量与时间的关系服从Logistic模型。翠竹实生苗的地径相同时,其高度与生物量之间呈显著线性关系。翠竹实生苗在大部分生长发育过程中,其地上部分干质量大于地下部分干质量。

Growth mechanisms and model fitting of module biomass of Pleioblastus pygmaeus seedlings

【Objective】This study focused on the growing regularity and model fitting of module biomass of a dwarf ornamental bamboo species, Pleioblastus pygmaeus (one-and-a-half year old seedlings), and will provide a theoretical basis for rapid propagation and centralization of small-sized bamboo seedlings.【Method】During the approximately one-and-a-half year growth process after sowing, we conducted a follow-up investigation on P. pygmaeus seedlings, including the plant height and ground diameter of the mother plants, emergence time, plant height and ground diameter of tillering seedlings, and appearance and development of bamboo rhizomes. Multiple morphological indicators, including dry weight of leaves and culms, plant height of tillering seedlings, and length of bamboo rhizomes, etc. were fitted by a logistic model and polynomial function. The relative growth curves of plant modules with time were analyzed. The relationship between plant height, ground diameter and biomass was investigated. The ratio of dry weight between aboveground and underground areas was examined.【Result】The seedlings were unearthed about 1 week after sowing. On the 11th day after sowing, the first leaf was fully expanded. The first generation of tillering seedlings appeared approximately three months after sowing. Primary bamboo rhizomes were generated approximately six months after sowing. One year after sowing, the culms on the primary bamboo rhrizome system grew vigorously. In one and a half year after sowing, the second and third-grade bamboo rhrizomes began to differentiate and grow. The ground diameter and plant height of tillering seedlings increased gradually with their differentiation. The module biomass of P. pygmaeus seedlings increased with time. With the same ground diameter, dry weight of culms increased with plant height. Within three months after sowing, the aboveground biomass of seedlings was greater than the underground biomass of seedlings, and their ratio showed an upward trend. Within three to seven months after sowing, the aboveground biomass was lighter than the underground biomass, and their ratio tended to show an upward trend. Within 10 months to one year after sowing, the aboveground part was heavier than the underground part, but the dry weight ratio of the former to the latter was initially increased and then decreased. In one year after sowing, the ratio of aboveground and underground dry weight showed a downward trend, but it gradually tended to be stable. 【Conclusion】This study systematically revealed the growth mechanism and dynamic growth process of various modules of P. pygmaeus seedlings between the period of sowing and stem elongation. The increase in module biomass of P. pygmaeus seedlings fitted into the logistic model with time during the growth process. When the ground diameter of P. pygmaeus seedlings was the same, there was a significant linear relationship between plant height and biomass. For most of the time during the growth process, the aboveground biomass of P. pygmaeus seedlings was greater than the underground biomass of P. pygmaeus seedlings.