Abstract: In order to clarify the response of growth and water use efficiency of oats to drought stress,the study was conducted for Avena sativa ‘Qingyan No. 1’ to understanding the effect of water deficit on oats growth and development. It found that plant height,stem thick and leaf area decreased obviously with increasing stress degree and time. Water deficit inhibited the increase of fresh weight of root,stem,leaf and spikelet,and the largest decrease occurred at the seedling-jointing stage,booting-heading stage,and flowering-milking stage under persistent moderate and severe drought. Drought stress affected the photosynthetic performance significantly. The transpiration rate decreased by 4.11~10.35 mmol·m^-2·s^-1,photosynthetic rate decreased by 3.10~16.59 μmol·m^-2·s^-1 and stomatal conductance decreased by 0.03~0.34 mol·m^-2·s^-1. After drought stress,water use efficiency(WUE) was the highest(4.95) at seedling-jointing stage and flowering-milking stage with the mild drought;the stable carbon isotope of each organ increased and decreased. Though correlation analysis,it found that △¹³C_sp was negatively correlated with WUE,and △¹³Cle and △¹³Cst were negatively correlated with WUE. In terms of the overall level,effects of different drought degrees and times on morphological characteristics,fresh organ weight and photosynthetic performance were as follows:three times of drought and moderate and severe stress had the greatest impact.

Key words: Oat, Drought stress, Organ growth, Water use efficiency

摘要： 为探究干旱胁迫后燕麦（Avena sativa）生长及水分利用的响应变化，本研究选择‘青燕1号’（Avena sativa ‘Qingyan No.1’）进行干旱胁迫处理，研究水分亏缺对燕麦生长发育的影响。结果显示：燕麦株高、茎粗和叶面积随着胁迫程度和次数增加下降明显；干旱胁迫抑制了根、茎、叶和穗鲜重的增加，各处理以苗期-拔节期、孕穗-抽穗期、开花-乳熟期持续性中度和重度干旱降幅最大；干旱胁迫后光合性能变化明显，蒸腾速率下降幅度达4.11~10.35 mmol·m^-2·s^-1，净光合速率降幅达3.10~16.59 μmol·m^-2·s^-1，气孔导度降幅达0.03~0.34 mol·m^-2·s^-1；干旱胁迫后燕麦水分利用效率（water use efficiency，WUE）以苗期-拔节期、开花-乳熟期轻度干旱处理最高（4.95），各器官稳定碳同位素分辨率（△¹³C）有增有减，其中△¹³C_sp与WUE呈极显著负相关，△¹³C_le和△¹³C_st与WUE呈显著负相关。整体水平来看，干旱胁迫程度和次数对燕麦形态特征、器官鲜重及光合性能的影响大小表现为：中度和重度胁迫、胁迫3次影响最大。

关键词: 燕麦, 干旱胁迫, 器官生长, 水分利用效率