Recovery responses of photosynthesis, transpiration, and WUE in black poplar clones following water deficits

Abstract

Five black poplar (Populus nigra L.) genotypes were grown in a semi-controlled environment and were subjected to three different soil water regimes: control (90-70% of maximal field capacity-FC), drought followed by recovery of optimal soil water saturation (90-40% of FC) and permanent drought treatment (50-40% of FC). Variation in leaf gas exchange parameters such as photosynthetic (P) and transpiration intensity (T), as well as water use efficiency (WUE) were investigated among genotypes in their response to water deficit and recovery from drought. Recovery of soil water field capacity from 40% to 90% determined restored values of P, T and WUE. After 16 days of permanent drought (50-40% FC), strong decline of all parameters among examined genotypes was determined. Overall, significant differences among genotypes in leaf gas exchange parameters were found, which can give some indications of superiority of certain genotypes in relation to drought stress.

Pet genotipova crne topole (Populus nigra L.) su u polu-kontrolisanim uslovima izloženi različitim vodnim režimima: optimalnoj zasićenosti vodom (kontrola), suši praćenoj oporavkom optimalnog vodnog kapaciteta i tretmanu konstantne suše. U odgovoru genotipova na vodni deficit i oporavak, ispitivane su promene parametara koji se odnose na razmenu CO2 i vodene pare u listu, kao što su intenzitet fotosinteze (P) i transpiracije (T) i efikasnost korišćenja vode (WUE). Ponovno podizanje vodnog kapaciteta zemljišta na 90%, nakon vodnog deficita pri kapacitetu od 40%, uslovilo je oporavak intenziteta fotosinteze, transpiracije i efikasnosti korišćenja vode na nivoe približne vrednostima kontrolnih biljaka. Nakon 16 dana konstantne suše (vodni kapacitet u opsegu 50-40%) utvrđeno je snažno opadanje analiziranih parametara u svim genotipovima. Značajne varijacije analiziranih parametara među genotipovima ukazuju na specifične adaptivne predispozicije određenih gentipova u odnosu na sušni stres.