Odgovor rastlin na povečane koncentracije CO 2 Ekofiziologija in mineralna prehrana rastlin
Spremembe koncentracije CO 2 v atmosferi merilna postaja Mauna Loa, Hawaii. koncentracija CO 2 [μmol mol -1 ] Leto Ekofiziologija in mineralna prehrana rastlin
Spremembe koncentracije CO 2 v atmosferi koncentracija CO 2 [μmol mol -1 ] Körner, 2006 Leta p.n.š. Ekofiziologija in mineralna prehrana rastlin
Spremembe koncentracije CO 2 v atmosferi kreda Milijoni let p.n.š. Lasaga et al. 1985 Koncentracija CO 2 v atmosferi [ppm] paleocen eocen oligocen miocen pliocen pleistocen
CO 2 H 2 O O 2 C 6 H 12 O 6
Odvisnost fotosinteze od koncentracije CO 2 Neto fotosinteza [μmol CO 2 m -2 s -1 ] 20 10 Ob sedanjih koncentracijah CO 2 v zraku ni dosežena maksimalna fotosinteza CO 2 je omejujoči dejavnik fotosinteze 200 400 600 800 Koncentracija CO 2 [μmol mol -1 ]
[CO 2 ] [CO 2 ] pridelek
Pričakovani neposredni učinki povečanje fotosinteze zmanjšanje prevodnosti listnih rež povečanje učinkovitosti izrabe vode CO 2 H 2 O CO 2
Proučevanje odziva rastlin na povečane konc. CO 2 rastne komore OTC open top chambers FACE free-air CO 2 enrichment Primerjava okoljski CO 2 (350 ppm) vs. povečan CO 2 (700 ppm)
Open top chambers
face.env.duke.edu/ Duke University FACE Experiment
face.env.duke.edu/ Duke University FACE Experiment
face.env.duke.edu/ Duke University FACE Experiment
face.env.duke.edu/ Duke University FACE Experiment
Swiss FACE Experiment http://www.gl.ipw.agrl.ethz.ch/research/closed/face
A schematic representation of four different types of CO2 responses of plants when CO2 exposure is initiated at the seedling or rooted cutting stage (type II growth conditions). (a) No CO2 effect; (b) continuous CO2 effect combined with compound interest effects (expanding system), leading to exponential growth; (c) initial effects as in (b) but no further stimulation after completion of canopy and root volume expansion; (d) initial effect as in (b) but return to control biomass after completion of the expansive phase. (a) and (d) responses to a step increase in CO2 may be very rare in expanding systems, but are possible in steady-state systems (d incurs a period of negative effects); (b) is impossible in nature, because it contravenes the law of limiting resources (except for short periods), so variants of (c) are most likely. Note that the constant difference between the two solid lines after the breakpoint in (c) results in diminishing relative responses with time. E, elevated; A, ambient CO2 concentration; P, phase (time) shift in plant development. Körner, 2006
Odziv fotosinteze v FACE poskusih Fotosinteza (povečan CO 2 / sedanji CO 2 ) lesne rastline zeli Vrsta / FACE poskus Liq, Liquidambar; Pin, Pinus; Pop, Populus; Bet, Betula; Amb, Ambrosia; Lar, Larrea; Lol, Lolium; Bro, Bromus; Koe, Koeleria; Agr, Agropyron; Tri, Trifolium; Sol, Solidago. Abbreviations for sites: TN, ORNL; NC, FACTS I; IT, PopFACE; WI, FACTS II; NV, NDFF; CH, ETH-Z; MN, BioCON; NZ, NZGraze. (Nowak et al., 2004)
Povečan CO2 / sedanji CO2 Neto primarna produkcija Produkcija nadzemne biomase Podatki z različnih FACE poskusov Nowak in sod., 2004
Species that showed the greatest reductions in leaf N-content at elevated [CO 2 ] also tended to show reduced enhancement in A net. (a) Relationship between Anet and leaf N content for plant species growing under ambient [CO 2 ] at different free-air CO 2 enrichment (FACE) sites. Each point is a different species, and different symbol shapes are the different FACE sites shown in (b). Solid line is a simple linear regression for data except for the two inverted triangles enclosed by the oval; these represent two species that do not fit the overall relationship. Open symbols are herbaceous species and closed symbols are woody species. (b) Enhancement ratio of Anet at elevated [CO 2 ] as a function of changes in leaf N content (leaf N content at elevated [CO2] divided by leaf N content at ambient [CO2]) for species from six FACE sites. Solid line is a simple linear regression for data. Each point is a different species, and different symbol shapes are the different FACE sites. Open symbols are herbaceous species and closed symbols are woody species. FACE sites: open triangle, NZGraze; open square, BioCON; open circles, ETH-Z; closed circles, FACTS I; closed diamond, FACTS II; closed downward-pointing triangle, NDFF; closed square, SAT; closed upward-pointing triangle, ORNL.
C 4 C4 rastline C3 rastline Koncentracija CO2 [μmol mol -1 ] C 3 Neto fotosinteza [μmol CO 2 m -2 s -1 ]
Atmosferska koncentracija CO 2 in temperatura pomembno vplivata na uspešnost rastlin s C 3 oz. C 4 metabolizmom
Povečana koncentracija CO 2 in odgovor rastlin različnih tipov Stimulacija povečanja nadzemne biomase pri rastlinah različnih tipov.
Odziv rastlin na povečane koncentracije CO 2 povečan CO 2 lahko deluje stimulativno na rast, če ni drugega dejavnika, ki bi bil pri tem omejujoč (primer N) pričakovati je, da bodo rastline ob povečanem CO 2 bolje izkoroščale vodo rastline različnih tipov (lesne, zeli, C 4, C 3 ) se bodo na povečanje CO 2 odzivale različno odziv rastlin na povečanje CO 2 in morebitno ponorno aktivnost je potrebno ovrednotiti ločeno za posamezne tipe ekosistemov Ekofiziologija in mineralna prehrana rastlin
? [CO 2 ] fotosinteza pridelek neposredne povezave v razmerju 1:1 ni
CO 2 Fotosinteza sladkorji Rast C rezerva Presnova Izvoz Listi Steblo Cvet / Plod Korenine Mikoriza Talni mikrobi Opad Hlapne C snovi Topni organski ogljik Avtotrofno dihanje Heterotrofno dihanje CO 2
Kroženje ogljika v kopenskih ekosistemih http://www.climatescience.gov
Meritve neto ekosistemske izmenjave C s tehniko Eddy covariance.