【作者】 齐学礼；

【导师】 许为钢； 邢邯；

【作者基本信息】 南京农业大学 ， 作物遗传育种， 2008， 硕士

【摘要】 在小麦生长后期经常遇到高温、强光、干旱等不利环境因子,并且高光强常伴随高温,使小麦旗叶光合速率下降,影响小麦的灌浆特性,造成减产,因此有必要研究不同基因型小麦耐高光强高温特性,为选育高光效小麦新品种和筛选高光效种质材料提供理论依据。本研究以黄淮麦区生产上应用的15份小麦品种为试验材料,采取田间种植和盆栽两种种植方式,研究了大田条件下小麦抽穗后旗叶的光合特性;对盆栽材料在灌浆期进行3h的强光(1900 mol·m^-2·s^-1)加高温（35℃）的处理,研究了高光强和高温交互胁迫对小麦旗叶的光合作用、叶绿素荧光特性、抗氧化酶活性、质膜过氧化的影响。研究结果如下:1.由5个时期气体交换参数的日变化曲线可以看出,小麦抽穗以后,旗叶光合速率最大值出现的时刻有逐渐提前的趋势,这与光照强度、大气温度的日变化有关。在抽穗期4月18日开花期以前各个材料旗叶间净光合速率（Pn）、蒸腾速率（Tr）、气孔导度（G_S）、胞间CO₂浓度（C_i）全天日变化差异并不十分明显。在4月25日和5月2日材料间Pn、Tr、G_S全天变化差异较大,而C_i差异不明显,在5月12日材料间气体交换参数只有Pn差异较大,Tr、G_S、Ci相差均不明显。非气孔因素是小麦后期材料间差异较大的主要原因,郑麦9405后期的光合特性优于其它品种。2.由4月25日和5月2日早上和中午时刻的荧光参数比较可以看出,两个时期12:00的PSⅡ最大光化学效率（Fv/Fm）较8:00均有下降,且藁城8901明显低于其它品种;两个时期12:00时刻的作用光下光系统Ⅱ的实际的量子效率(Φ_PSⅡ)和光化学猝灭系数（qP）较8:00时刻均出现下降,但郑麦9405高于其它品种;两个时期12:00时刻的非光化学猝灭系数（NPQ）较8:00时刻均出现上升,郑麦9405明显高于其它品种,PSⅡ受到抑制较轻,对中午时刻强光高温具有较好的耐胁迫能力。3.4月28日之前四个小麦旗叶叶绿素含量未出现明显变化,且品种间差异不大,SPAD值均维持在50-55之间。到5月16日此时已经处于小麦灌浆后期,各个材料旗叶的叶绿素含量均出现大幅度下降,伴随净光合速率的快速下降,而此时郑麦9405的SPAD值明显高于其它材料仍保持30以上,光合速率仍接近10μmolCO₂·m^-2·s^-1伴随生育期的进程各材料旗叶的Φ_PSⅡ、qP和NPQ均呈现逐渐下降的趋势,郑麦9405各项荧光参数均较高,各材料的Fv/Fm在5月10日以前各材料均未出现明显变化,到5月16日出现快速下降,郑麦9405下降幅度最小。郑麦9405的持绿期和光合功能期较长。4.强光高温处理后,各个材料旗叶的Pn、Tr、G_S较对照都出现较大幅度下降;郑麦9405的Pn、G_S也出现下降,但降幅最小,E较对照略有上升;四种基因型小麦的C_i较对照未出现明显变化;处理后与对照相比四个材料的Fv/Fm、Φ_PSⅡ、qP均出现下降,而NPQ出现大幅上升;其中郑麦9405的各项荧光参数均为最大;处理后四个小麦旗叶的超氧化物歧化酶（SOD）活性未出现明显变化,抗坏血酸过氧化物酶（APX）活性出现不同程度下降,郑麦9405的过氧化氢酶（CAT）和过氧化物酶（POD）活性升幅大于其它三品种;处理后郑麦9405旗叶的超氧阴离子和丙二醛的含量升幅小于其它三品种。总之,小麦旗叶对强光高温的耐性存在基因型间差异,郑麦9405小麦旗叶的耐高光强高温特性优于藁城8901和周18两类品种;较高的蒸腾速率,较大的NPQ,较高的抗氧化酶活性以及后期较高的叶绿素含量可能是郑麦9405类小麦品种维持较高光合速率的原因。更多还原

【Abstract】 Wheat （Triticum aestivum L.） crops often submitted to high temperature, high light or drought at later growth stage. High light is often associated with high temperature, which has a strong impact on photosynthesis and causes loss in wheat grain yield. It is necessary to explore the differences to high light and high temperature among wheat cultivars.We take 15 wheat cultivars grown in Huanghuai wheat zone as the material, the photosynthetic characteristics under field conditions and high light intensity (1900 mol·m^-2·s^-1) associated with high temperature （35℃） were studied among them.The results are as follows:1. The appeared time of maximum net photosynthetic rate in the morning was advaced with the date process, it was related to light and temprature. There were no significant differences in the diurnal variation of net photosynthetic rate （Pn）, transpiration rate （Tr） and stomatal conductance （Gs） before April 18^th, but significant differences were observed on April 25^th and May 2^nd. The diurnal variation of Intercellular CO₂ concentration （C_i） has no significant differences in all days. The Pn, Tr and Gs in Zhengmai9405 were better than others at later stages. The mainly reason for the differences is the Non-stomatal limitations.2. There were no significant differences in the maximum photochemical efficiency （F_v/F_m） at 8:00 on April 25^th and May 2^nd. Compared with the fluorescence parameters at 8:00, F_v/F_m at 12:00 decreased on April 25^th and May 2^nd, F_v/F_m in GaoCheng was lower than others at 12:00, both the actual photochemical efficiency of photosystemⅡ(Φ_psⅡ and the photochemical quenching （qP） at 12:00 decreased while the non-photochemical quenching （NPQ） increased significantly in four cultivars, and each of the chlorophyll fluorescence parameters in Zheng Mai 9405 was the highest among the cultivars. PSⅡin Zhengmai 9405 was slightly inhibited, had better adaptability to the high light and high temperature at noon.3. The level of the relative chlorophyll content in all cultivars was steady before April 28^th, and no significant differences among them, it deduced significantly till May 16^th . At this time Pn decreased greatly, too. The SPAD value of Zhengmai is 30 and Pn is 10μmolCO₂·m^-2·s^-1, both index are higher than others. TheΦ_psⅡ, qP and NPQ decreased form April 25^th to May 16^th. There was no significant differences in the Fv/Fm before May 10^th, it decreased significantly till May 16^th·Φ_psⅡ, qP, NPQ and Fv/Fm in Zhengmai 9405 were the highest among them at all growth stages. Zhemgmai 9405 has longer green lasting period, so it can keep a long photosynthetic function period.4. The results showed after treatment with high light intensity and high temperature, different appearances were observed compare with the control in the cultivars: Pn, Tr, Gs in all cultivars were significantly reduced; Pn and Gs of Zhengmai 9405 decreased slightly and E increased slightly nevertheless; C_i didn’t vary significantly in all cultivars. Fv/Fm, the efficiency of open centers of photosystemⅡ（Fv’/Fm’）,Φ_psⅡ, and qP decreased while NPQ increased significantly in the cultivars, and the five chlorophyll fluorescence parameters of ZM9405 were the highest among them. The activity of SOD didn’t vary significantly and the activity of APX decreased inconsistently in all four cultivars, the activity of CAT and POD of Zhengmai 9405 increased higher than the other three. The content of （?） and MDA in Zhengmai 9405 were lower than the others after the treatment.更多还原