Establishment of a shortened annual cycle system; a tool for the analysis of annual re-translocation of phosphorus in the deciduous woody plant (Populus alba L.)

Abstract

The supply of phosphorus, the essential element for plant growth and development, is often limited in natural environments. Plants employ multiple physiological strategies to minimize the impact of phosphate deficiency. In deciduous trees, phosphorus is remobilized from senescing leaves in autumn and stored in other tissues for reuse in the following spring. We previously monitored the annual changes in leaf phosphate content of white poplar (Populus alba) growing under natural conditions and found that about 75 % of inorganic and 60 % of organic leaf phosphates observed in May were remobilized by November. In order to analyze this process (such annual events), we have established a model system, in which an annual cycle of phosphate re-translocation in trees can be simulated under laboratory conditions by controlling temperature and photoperiod (='shortened annual cycle'). This system evidently allowed us to monitor the annual changes in leaf color, phosphate remobilization from senescent leaves, and bud break in the next spring within five months. This will greatly facilitate the analysis of cellular and molecular mechanisms of annual phosphate re-translocation in deciduous trees.

Short day length-induced decrease of cesium uptake without altering potassium uptake manner in poplar

“…Under a controlled growth cycle system in Populus alba L., the shift from long-day (LD) to short-day (SD) conditions decreased phosphate in the lower leaves27. This change suggests the existence of mechanisms for the re-translocation of phosphate from older- to younger (upper) leaves in response to with seasonal changes.…”

Application of the Artificial Annual Environmental Cycle and Dormancy-Induced Suppression of Cesium Uptake in Poplar

“…Under the artificial annual environmental cycle using Populus alba L., the shift of growth condition from Long Day (LD) to Short Day (SD) condition decreased the phosphate contents in lower leaves (Kurita et al 2014). This change of phosphate content suggested the existence of a mechanism for the re-translocation of phosphate from lower leaves to younger upper leaves with seasonal changes.…”

“…The annual cycle of poplar growth is re-created in the artificial annual environmental cycle, which is a modification of a similar method by Kurita et al (2014). The poplar was treated with three stages: Stage-1 (Spring and Summer) 23 °C, 16 h light /8 h dark, Stage-2 (Autumn) 23 °C, 8 h light/16 h dark and Stage-3 (Winter) 4 °C, 8 h light/16 h dark (Table 10.1).…”

“…Poplars can break its dormant bud after the return to Stage-1 within 2 weeks. In our artificial annual environmental cycle, in contrast to Kurita et al (2014), the temperature in Stage-2 was set to 23 °C. Our preliminary experiments revealed that the dormant bud formation can be triggered by 4 weeks of short day-length treatment when the temperature is less than 23 °C.…”

Effect of dormancy on the development of phloem fiber clusters

“…As all trees were grown for the same duration, any tissues formed are directly comparable without correction or adjustment. We have previously established a shortened annual cycle system for poplar trees using growth chambers [5]. This system comprises three stages and includes dormancy and dormancy breaks every 4-5 months.…”