Evolutionary adaptation strategies of ploidy wheats and oats to abiotic stresses

摘要

High temperature stress adversely influence growth of crop plants and always result in low yield, but the relevant adaptive strategies due to different selective pressure experienced by crop plants is still unclear.In this study, we selected eight varieties which are in different evolutionary period, and set two experimental conditions: 30℃/25℃ * 200 PAR as high temperature and low light intensity, while 20℃/15℃ * 200 PAR as control.The result suggested that diploid and tetraploid crops which experienced natural acquired avoidance strategy, and they have lower adaptability for abiotic stresses and also lower final yield.Diploid and tetraploid crops exhibited reduction in tiller number, increase in biomass allocation to vegetative tissues, and sustain their lives through leaf rolling and improved leaf glaucous to avoid high temperature and low light intensity stresses.Through experiencing artificial selection modern hexaploid crops and oats acquired tolerance mechanisms to high temperature and low intensity, further they have higher adaptability for abiotic stresses and maintain higher final yield.Proline and soluble sugar contents showed higher concentration under stress conditions in these cultivars, and displayed better adaptability to high temperature and low light conditions with maintaining larger green leaf area and higher relative water content.