摘要
根据物候观察,生长速度测定和某些生理指标的材料,在我们的试验中把毛白杨的年生育过程分为六个时期:1、萌动期;2、展叶拔节期,即生根初期;3、新梢生长停滞期,即生根临界期;4、二次生长期;5、封顶充实期;6、越冬休眠期。 在插条苗的发育过程中观测了下列主要生理特点: 1、插穗中贮藏的营养物质在扦插后不断消耗。直到二次生长开始前(6月中旬)插穗中没有积累新的营养物质。 2、从四月中旬到五月初,尚未生根的插条苗中发生水分亏缺。到五月末水分亏缺变得十分严重,其水分饱和差达25—29％。 3、处在生根临界期的插条苗其光合作用由于水分亏缺而中断或受到抑制。
Based on phenological observations, rate of shoot growth and some physiologicalchanges six stages of the seasonal growth of Populus tomentosa Carr.cuttilgs maybe recognized as follows: 1. swelling of bud;2. leaf exponsion and shoot elongation root initiation: 3.suspension of new shoot growth a Critical period for rooting,4. resumption of sho-ot growth;5. hardenning stagel 6. stage of dormancy. In the course of rooting some physiological changes of the cuttings observedwere: 1. Nutrients stored in the cuttings were continually consumed after plauting.Nonew nutrients would be available until the resumption of shoot growth(in mid-june) 2. From mid-April to early May, water deficit was apparent in un-rooted cuttin-gs. By end of May, water deficit became even more serious.amonuting to 25-29%. 3. Photosynthesis of cuttings in critical state of rooting was suspended or inhib-ited due to lack of water.
