Growth rhythm and models of the Ulmus pumila L.on nursery stage
The annual growth rhythms of basal diameter and seedling height in one-year-old grafted seedlings of seven Ulmus pumila L.clones were investigated,and growth curves were modeled using the Logistic equation.The results demonstrated that Ulmus pumila L.exhibited intermittent growth characteristics during the nursery stage,following a typical S-shaped growth curve with a"slow-fast-slow"pattern.The growth process included three to four distinct growth peaks,with minimal differences between peak values.Notably,basal diameter growth lagged behind seedling height growth.The seedlings exhibited an extended growth period,characteristic of a full-season growth type.Among the clones,Clone 225 showed superior performance in terms of height growth,with both faster growth rates and longer durations of rapid growth compared to other clones.Conversely,Clone 43 exhibited the lowest growth performance.The Logistic equation provided a highly accurate fit,with correlation coefficients exceeding 0.97 for all cases.The seedling growth process of Ulmus pumila L.was divided into three phases:pre-growth period,fast-growth period and post-growth period.During the fast-growth period,growth increments accounted for 65.4％-81.7％of the total growth.These findings suggest that nursery management practices should be tailored to the specific growth characteristics at different developmental stages.
万方数据
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