荧光分析描述方法的好文章--Hydrogen_peroxide_production_is_an(8)

1428common event along with H2O2 production inresponse to ABA or MJ (Pei etal. 2000; Zhang etal.2001; Suhita etal. 2004). In contrast, a change in CO2partial pressure from 100 to 1000ppm did not evokeany cytoplasmic pH change in V. faba guard cells(Brearley etal. 1997). In accordance, we observed thatthe eVect of bicarbonate seems independent of a cyto-plasmic pH change since butyrate (a permeant weakacid) had no signiWcant eVect on the bicarbonate-induced stomatal closure (data not shown).Sources of bicarbonate-induced H2O2 in guard cellsIn plant cells, H2O2 can be produced in multiple ways(Park etal. 2003; Apel and Hirt 2004). One of the well-known sources of H2O2 in guard cells is the plasmamembrane NAD(P)H oxidase (Murata etal. 2001;Kwak etal. 2003; Suhita etal. 2004). Membrane peroxi-dation occurs during stress conditions leading to a sig-niWcant production of ROS (Montillet etal. 2004). Thebicarbonate-induced H2O2 production in guard cellswas diminished by DPI (Fig.7). The absence of H2O2production as well as stomatal closure in response tobicarbonate in atrbohD/F double mutant of Arabidop-sis (Fig.5) provided convincing genetic evidence thatNAD(P)H oxidase was responsible for bicarbonate-induced H2O2 production in guard cells. These observa-tions suggest that H2O2 production in response to bicar-bonate results from NAD(P)H oxidase. Externaladdition of H2O2 enhanced DCF Xuorescence of guardcells in both wild and Atrhoh D/F mutants (Fig.7) indi-cating that NAD(P)H oxidase was the major source ofinternal production of H2O2. Organelles containingelectron transport systems, such as mitochondria andchloroplasts, can also produce H2O2 (Asada 1999),although the direct involvement of such processes insignaling is not yet clear. Zhang etal. (2001) detectedH2O2 in chloroplasts and in the cytosol of guard cells.There are reports that PP2C, protein kinase and PI3Pcould directly or indirectly regulate ROS production inguard cells, particularly during ABA signaling (Murataetal. 2001; Mustilli etal. 2002; Park etal. 2003). Thereversal of stomatal closure (Fig.4) as well as restric-tion of H2O2 production (Fig.8) by wortmannin andLY 294002 suggests that PI3P is involved in the signal-ing of not only ABA but also bicarbonate in guard cells.H2O2 is a possible secondary messenger during CO2 response

ROS production appears to be a dynamic event duringplant development as well as plant response to bioticand abiotic stresses (Apel and Hirt 2004). We there-

123

Planta (2007) 225:1421–1429

fore suggest that H2O2 could be an important second-ary messenger during the transduction of CO2 signal innot only guard cells but also other plant tissues. TheH2O2 production in guard cells appears to be an earlyevent on exposure to bicarbonate.

AcknowledgmentsThis work was supported by grants fromIndo-French Centre for the promotion of Advanced Research (toA.S.R and A.V, No. 2203-1) and Council of ScientiWc and Indus-trial Research (No. 38(0949)/99/EMR-II) both from New Delhi;and a senior research fellowship (to V.A.K) from Institute of LifeScience Grant to University of Hyderabad. We thank ProfessorJulian Schroeder for providing the atrbohD/F double mutantseeds of Arabidopsis. We thank C. S. Murthy, Sr. ScientiWc OY-cer, Central Instrumentation Laboratory for his constant help inusing confocal microscope.

References

Apel K, Hirt H (2004) Reactive oxygen species: metabolism, oxi-dative stress, and signal transduction. Annu Rev Plant Phys-iol Plant Mol Biol 55:373–379

Asada K (1999) The water-water cycle in chloroplasts: scavenging

of active oxygens and dissipation of excess photons. AnnuRev Plant Physiol Plant Mol Biol 50:601–639

Assmann SM (1993) Signal transduction in guard cells. Annu Rev

Cell Biol 9:345–375

Assmann SM (1999) The cellular basis of guard cell sensing of ris-ing CO2. Plant Cell Environ 22:629–637

Brearley J, Venis MA, Blatt MR (1997) The eVect of elevated

COL. guard cells. Planta 203:145–154

2 concentrations on K+ and anion channels of Vicia fabaCross AR, Jones OTG (1986) The eVect of the inhibitor diphen-ylene iodonium on superoxide-generating system of neu-trophils. Biochem J 237:111–116

Edwards A, Bowling DJF (1985) Evidence for a COTradescantia vir-2 induced

proton extrusion pump in stomatal cells of giniana. J Exp Bot 36:91–98

Ellson CD, Gobert-Gosse S, Anderson KE, Davidson K, Erdju-ment-Bromage H, Tempst P, Thuring JW, Cooper MA, LimZY etal (2001) PtdIns(3) P regulates the neutrophil oxidasecomplex by binding to the PX domain of p40(phox). NatureCell Biol 3:679–682

Giraudat J (1995) Abscisic acid signaling. Curr Opin Cell Biol

7:232–238

Hauser M, Eichelmann H, Heber U, Laisk A (1995) Chloroplast

pH values and buVer capacities in darkened leaves as re-vealed by CO2 solubilization in vivo. Planta 196:199–204Havir EA, McHale NA (1989) Regulation of catalase activity in

leaves of Nicotiana sylvestris by high CO89:952–957

2. Plant PhysiolJung JY, Kim YW, Kwak JM, Hwang JU, Young J, Schroeder JI,

Hwang I, Lee Y (2002) Phosphatidylinositol 3- and 4-phos-phate are required for normal stomatal movements. PlantCell 14:2399–2412

Kolla VA, Suhita D, Vavasseur A, Raghavendra AS (2004)

Reevaluation of stomatal responses to bicarbonate in abaxialepidermis of Commelina benghalensis in comparison to theeVects of abscisic acid. J Plant Biol 31:117–123

Kwak JM, Mori IC, Pei ZM, Leonhardt N, Torres MA, Dangl JL,

Bloom RE, Bodde S, Jones JD, Schroeder JI (2003) NADPHoxidase AtrbohD and AtrbohF genes function in ROS-depen-dent ABA signaling in Arabidopsis. EMBO J 22:2623–2633

百度搜索“77cn”或“免费范文网”即可找到本站免费阅读全部范文。收藏本站方便下次阅读，免费范文网，提供经典小说教育文库荧光分析描述方法的好文章--Hydrogen_peroxide_production_is_an(8)在线全文阅读。