CPlants can’t communicate by moving or making sounds, as most animals do. Instead, plants

C

Plantscan’tcommunicatebymovingormakingsounds,asmostanimalsdo.Instead,plantsproducevolatilecompounds,chemicalsthateasilychangefromaliquidtoagas.Aflower’ssweetsmell,forexample,comesfromvolatilecompoundsthattheplantproducestoattr actinsectssuchasbugsandbees.

Plantscanalsodetectvolatilecompoundsproducedbyotherplants.Atr eeunderattackbyhungryinsects,forinstance,maygiveoffvolatilecompoundsthatletothertr eesknowabouttheattack,Inresponse,theothertr eesmaysendoffchemicalstokeepthebugsaway-orevenchemicalsthatattr actthebugs’naturalenemies.

Nowscientistshavecreatedaquickwaytounderstandwhatplantsaresaying:achemicalsensor(传感器)calledanelectr onicnose.The“e-nose”cantellcompoundsthatcropplantsmakewhenthey’reattacked.Scientistssaythee-nosecouldhelpquicklydetestwhetherplantsarebeingeatenbyinsects.Buttodaytheonlywaytodetectsuchinsectsistovisuallyinspectindividualplants.Thisisachallengingtaskformanagersofgreenhouses,enclosedgardensthatcanhousethousandsofplants.

Theresearchteamworkedwithane-nosethatr ecognizesvolatilecompounds.Insidethedevice,13sensorschemicallyreactwithvolatilecompounds.basedontheseinteractions,thee-nosegivesoffelectr onicsignalsthatthescientistsanalyzeusingcomputersoftware.

Totestthenose,theteampresenteditwithhealthyleavesfromcucumber,pepperandtomatoplants,allcommongreenhousecrops.Thenthescientistscollectedsamplesofairarounddamagedleavesfromeachtypeofcrop.Theseplantshadbeendamagedbyinsects,orbyscientistswhomadeholesintheleaveswithaholepunch(打孔器).

Thee-nose,itturnsout,couldidentifyhealthycucumber,pepperandtomatoplantsbasedonthevolatilecompoundstheyproduce.Itcouldalsoidentifytomatoleavesthathadbeendamaged.Butevenmoreimpressive,thedevicecouldtellwhichtypeofdamage–byinsectsorwithaholepunch–hadbeendonetothetomatoleaves.

Withsomefinetuning,adevicelikethee-nosecouldonedaybeusedingreenhousestoquicklyspotharmfulbugs,theresearcherssay.Adevicelikethiscouldalsobeusedtoidentifyfruitsthatareperfectlyripeandreadytopickandeat,saysNataliaDudareve,abiochemistatPurdueUniversityinWestLafayette,Ind.whostudiessmellsofflowersandplants.Hopefully,scientistsbelieve,thedevicecouldbringlargebenefitstogreenhousemanagersinthenearfuture.

49.Welearnfromthetextthatplantscommunicatewitheachotherby______.

A.makingsomesoundsB.wavingtheirleaves

C.producingsomechemicalsD.sendingoutelectr onicsignals