首页 | 本学科首页   官方微博 | 高级检索  
   检索      


Pattern of Respiration of a Perennial Ryegrass Crop in the Field
Authors:JONES  M B; LEAFE  E L; STILES  W; COLLETT  B
Institution:The Grassland Research Institute Hurley, Maidenhead, Berkshire, SL6 5LR
Abstract:‘Dark’ respiratory losses of CO2 were measured ona one year old sward of S24 perennial ryegrass (Lolium perenneL.) at intervals during a 74 day reproductive growth period,between April and June, and a 21 day vegetative growth period,in July and August. Part of the sward was shaded for one weekbefore measure ments commenced. Measurements of ‘dark’respiration continued for 46 hand it was possible to distinguishtwo components which are designated ‘maintenance’and ‘synthetic’ ‘Maintenance’ respiration was taken to be the meanrate of CO2 efflux after 40–46 h darkness. When calculatedon a plant d. wt basis at 15°C it ranged between 6 to 32mgCO2 g-1 day-1 during reproductive growth and 10–14 mgCO2 g-1 day-1 during vegetative growth. During reproductivegrowth, sward protein content ranged between 7–23 percent and when maintenance respiration was recalculated on thebasis of protein content it changed relatively little throughoutthe growth period (90–140 mg CO2 g pro tein-1 day-1);the value for vegetative growth ranged between 70–100mgCO2 g protein-day-1. Total ‘synthetic’ CO2 flux was determined duringreproductive growth and a rate of ‘synthetic’ CO2flux was determined during both reproductive and vegetativegrowth. Between 15 and 35 per cent of the CO2 fixed in the previousphotoperiod was lost in ‘synthetic’ respirationof above-ground material in reproductive swards. Previous shadingincreased the proportion of ‘synthetic’ CO2 lossfrom above ground. The rate of ‘synthetic’ CO2 outputduring the first hours of darkness increased with amount ofCO2 fixed in the previous photoperiod, although it was not proportionalto it. There is some evidence that assimilate is ‘carried-over’from one photoperiod to the next.
Keywords:
本文献已被 Oxford 等数据库收录!
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号