中文摘要：

【目的】为了探究不同生长阶段水分胁迫对旱区冬小麦生长发育和产量形成的影响,通过2012—2013和2013—2014两个生长季在遮雨棚人工控水试验,对比分析不同分段受旱条件下冬小麦的株高、叶面积指数、生物量、物候期和产量等生理生态指标的动态变化过程。【方法】试验将冬小麦整个生育期划分为越冬、返青、拔节、抽穗和灌浆5个主要生长阶段,每相邻两个生长阶段连续受旱,形成4个不同的受旱时段水平（D1—D4）,根据小麦生育期的需水量,设置灌水定额分别为40和80 mm两个水平（I1和I2）,共形成8个处理,每处理3次重复,在遮雨棚内采用裂区试验布置,此外在旁边设置1个各生育期全灌水的对照处理。【结果】在冬小麦营养生长阶段进行连续水分胁迫时,明显影响小麦的正常生长发育,越冬期和返青期受旱时冬小麦的株高和叶面积指数都最小,但是拔节后受旱对小麦植株生长影响不明显,且拔节期后冬小麦株高和叶面指数的平均生长速率均为拔节前的10倍;拔节期前各处理小麦的生物量都没有明显的差异,但是拔节后各处理差异明显,越冬期和返青期受旱处理的生物量明显低于其他各处理,并且后期复水也不能弥补生物量的严重损失;干旱胁迫能缩短冬小麦的生育期,在同一灌溉水平下,受旱阶段D1、D2、D3、D4的抽穗期和开花期比对照处理延迟1-3 d,且受旱时期越早、胁迫程度越大,则生育期越提前,成熟期最多可提前5 d;相同灌溉水平下,若抽穗和灌浆期受旱（即越冬、返青、拔节期灌水）可获得较高的有效穗数和穗粒数,但千粒重较低;而抽穗和灌浆期灌水,可以提高冬小麦千粒重,但穗数和穗粒数较低;在I1和I2水平下,越冬期和返青期受旱处理的产量最低,仅为对照处理产量的42%左右,但I1水平下拔节期和抽穗期受旱的处理产量最高,约为对照处理的63%,I2水平下返青

英文摘要：

【Objective】 The aim of this study is to develop an effective preparation process for obtaining highly active antioxidant peptide derived from wheat germ albumin using two-step dual-enzymatic hydrolysis.【 Method 】 A two-step dual-enzymatic hydrolysis and separation were employed to screen the antioxidant peptide（AOP） from wheat germ albumin.The in vitro AOP＇s antioxidant activity was evaluated by DPPH radical scavenging activity and Fe^2＋ chelating ability assays.The hydrolysate derived from tryptic hydrolysis of wheat germ albumin was fractionated by ultrafiltration according to molecular weight;then the fractions with high antioxidant capacity were further isolated by gel filtration chromatography（Sephadex G-75）.After that,the fraction with higher antioxidant activity was further hydrolyzed by an alcalase,and the hydrolysate was subjected to purification by Sephadex G-15 gel filtration chromatography and reversed-phase HPLC（RP-HPLC）,respectively.The highest antioxidant fraction was achieved and the structure was identified by ESI-TOF MS/MS.【Result】 Hydrolysate derived from tryptic hydrolysis of wheat germ albumin was fractionated by ultrafiltration according to molecular weight.Three fractions,Pa,Pb and Pc were obtained from the fraction with high antioxidant capacity.The fraction Pb showed the strongest antioxidant activity evaluated by DPPH radical scavenging activity and Fe2＋ chelating ability assays and its extraction yield was 23.1%.The fraction Pb which had the highest antioxidant activity was further hydrolyzed by an alcalase,and the hydrolysate was subjected to gel filtration chromatography（Sephadex G-15） and two more groups,Pd and Pe were obtained.The extraction yield of fraction Pd which had higher antioxidant capacity was 52.1%.After further purification by RP-HPLC,five fractions,P_1,P_2,P_3,P_4 and P_5 were separated from the fraction Pd,and the fraction P_3 exhibited the highest antioxidant activity with the in vitro EC50 values of DPPH radical scavenging activity a