微根窗(minirhizotron)技术及其应用.ppt

1、微根窗（minirhizotron）技术及其应用Development of new fine roots to replace dying or dead ones (a process called root turnover) is metabolically expensive and may account for 30% of global terrestrial net primary production (NPP) (Jackson et al., 1997). Their role in the soil environment often draws comparison

2、s with the role of leaves in the aerial environment (Tjoelker et al., 2005).,根系研究,土钻技术研究根系生产力和周转（常用最大最小法、续批差值累积法等） 同位素标记技术研究根系生产力和周转 Minirhizotron技术BTC： 无损伤原位监测 可测量根深、根长密度、根系动态、病理病变、根系生产力和周转、生长率和死亡率、根系分布等,微根管（minirhizotrons）,玻璃最好但很难用，一年后1/3破碎 丙烯酸（Acrylic）比较好，有研究认为用于森林优于丁酸酯 勒克森聚碳酸酯（Lexan） 树脂玻璃（Plexig

3、las） 聚碳酸酯（Polycarbonate） 丁酸酯（Butyrate） PVC,微根窗技术The modern minirhizotron system usually consists off (1) a transparent observation tube installed into the soil at each sampling position; and (2) a video camera system which includes a miniature video camera, a TV moni- tor, a video cassette recorder

4、(VCR) and other accessories.,BTC-2与BTC-100,BTC-Borescope,Site (plant species): Arctostaphylos hookeri,A frog! This individual was sitting on one of our rhizotron tubes. When we approached to gather some images, she tried to withdraw further into the ground, but his body remained pressed up against t

5、he rhizotron tube. So, we photographed her from below,This is either a very small worm or a very large nematode!,Site (plant species): Cupressus abramsiana,Zoom in on mycorrhizal roots; note the mystery invertebrate in the lower left corner,Dense hyphal mats.the invertebrate is much more visible,Sit

6、e (plant species): Quercus agrifoliaFecal pellets. We dont know what kind of animal left them here, however,Site (plant species): Eucalyptus sp.Invertebrate foraging on root.,Site (plant species): Eucalyptus sp.A thick hairy root overlaid with branched young root. Notice the grub at lower left.,Site

7、 (plant species): Banksia spinulosaNotice the spider! This predator was waiting out the midday sun in her underground burrow.,Site (plant species): Quercus agrifoliaRoot network with hyphal colonization,Site (plant species): Quercus agrifoliaWispy, branched thin white root.bacterial clumps on right

8、side of the screen?,Site (plant species): Genista monspessulanaCould be more root hairs, but the assymetry suggests that some of those wispy threads may be fungal.,Site (plant species): Sequoia sempervirens (A)Red bulbous fungi-like structure. Or perhaps it is a hardened flow of sap from a root.we c

9、ant figure this one out! Notice the deep rooting channel in the background,Site (plant species): Sequoia sempervirens (B)Another fungal-infected root,Site (plant species): Quercus agrifoliaRoot hair clear and fully developed,Site (plant species): Quercus agrifoliaYoung root, fine hairs,Site (plant s

10、pecies): Protea neriifoliaFull zoom on the root tip with characteristic brush-like dense root hairs. This is a classic example of a proteoid root.,Site (plant species): Cupressus abramsianaIntense mycorrhizal colonization. The roots are hard to distinguish,Fine-root production dominates response of

11、a deciduous forest to atmospheric CO2 enrichment,Fig. 1. Seasonal dynamics of fine roots were determined by analysis of minirhizotron images collected biweekly during the growing seasons from February 1998 to November 2003. (A) Production during an observation interval was calculated as the length o

12、f new roots plus increases in length of existing roots. (B) Mortality is the disappearance of roots during an interval, with corrections made for roots that subsequently reappear. (C) Standing crop is the total length of root visible; changes in standing crop generally reflect production minus morta

13、lity. Data are expressed as the length of root per square meter of observation window. Pooled SEs for each year are shown.,Fig. 3. Distribution of fine-root length by depth in soil at the time of peak standing-root length in 1998 and 2003. Data are the means SE of three ambient and two elevated plot

14、s, based on analyses of five minirhizotron tubes per plot and expressed as length per square meter of observation window. CO2 had a significant effect on root length at 015 cm (P 0.035), 3045 cm (P 0.001), and 4560 cm (P 0.013) but did not at 1530 cm. The patterns in intervening years were intermediate to those shown here.,Fig. 4. Relationship between N uptake and root-length duration. N uptake per plot for each year (19982002) was calculated as the N content (dry matter production times N concentration) of woody increment, leaf