【作者】 李晓东；

【导师】 樊军锋；

【作者基本信息】 西北农林科技大学 ， 林木遗传育种， 2015， 硕士

【摘要】 低温是限制植物生长发育与地域分布的主要生态因子之一。杨树作为我国北方重要的造林与生态防护树种,其周期性冷害极大制约了杨树产业的发展。故经低温逆境研究杨树抗性生理,对明晰杨树抗寒调节机理,判别杨树的适生栽培地域及我国北方生态环境的建设具有十分重要的意义。本研究经由美洲黑杨×青杨派优良杂种无性系开展低温逆境胁迫,测定分析低温逆境下杨树杂种无性系的抗性生理指标;探讨分析钙信号系统对杨树幼苗低温抗逆生理的影响。主要结果如下:1经由枝条失水率、LT50、SOD与POD活性及MDA与可溶性蛋白(SP)含量等生理指标对杨树各杂种无性系开展度量评定表明,9个杨树杂种无性系的抗寒性表现为:07-69×青1>06-69×卜1>06-57×川1>中绥12号>07-西大寨×卜1>陕林4号>08-69×青2>08-69×青4>E24-01;9个杨树杂种无性系的抗寒性具较大差异,杂种无性系07-69×青1低温逆境生理抗性表现最强,具最强抗寒性,杂种无性系E24-01低温逆境生理抗性表现最差,具较弱抗寒性;并9个杨树杂种无性系的LT50差异表现明显,可开展系间筛育。2抗寒杂种无性系07-69×青1枝条失水率、LT50与MDA含量表现低于另8个杨树杂种无性系,枝条SOD与POD活性及可溶性蛋白(SP)含量表现高于另8个杨树杂种无性系,其低温抗性表现最强;低温逆境下杂种无性系07-69×青1枝条SOD与POD活性及SP含量随低温逆境均呈先升后降趋势,枝条MDA含量随低温逆境呈上升趋势,整体呈“S”型。3陕林4号与07-69×青1幼苗经由不同浓度Ca2+的叶面增施表明:低温逆境下增施一定浓度(5~15mmol/L)Ca2+可提升杨树幼苗质膜系统结构的低温稳定性、抗氧化系统活性及低温抗性物质累积;高浓度增施则不利其抗寒提升;10mmol/L Ca2+增施效值表现最佳,可显著降低杨树幼苗的膜伤害率与MDA含量,提升株体SOD、POD与可溶性蛋白(SP)含量,缓轻杨树幼苗的低温伤损。4陕林4号与07-69×青1幼苗经由EGTA及TFP的叶面增施表明:杨树幼苗Ca2+低温信号转导被阻断抑制,其杨树抗寒生理参控效能被削弱,低温逆境下杨树幼苗质膜系统结构的低温稳定性、抗氧化系统活性及低温抗性物质累积表现降低,杨树整体的低温抗寒提升作用被抑制。5陕林4号扦插苗经由Ca(NO3)2、CaCl2与Ca(Ac)2三种钙盐的叶面增施表明:增施钙盐可显著降低低温逆境下陕林4号扦插苗的膜伤害率、LT50及MDA含量,提升株体抗氧化酶的活性,增进株体低温抗性物质的累积,稳定杨树幼苗抗逆代谢生理的稳态,缓轻低温逆境对杨树幼苗的伤损,且三种钙盐对杨树幼苗的抗寒提升效能差异显著,表现为CaCl2>Ca(NO3)2>Ca(Ac)2。更多还原

【Abstract】 Low temperature is one of the most important environmental factors limiting the growth and distribution of plants. Poplar is an important afforestation and greening tree species in Northern China. However, periodic cold injury and its damagement have been resulted in some serious problems to the development.of poplar industry. Therefore, it is necessary to study physiological and biochemical response of different cultivars to low temperature. It was significant to elaborate the mechanism of cold resistance, distinguish the adaptability of different cultivars and the construction of the ecological environment in Northern China.In this paper, the hybrids of Populus deltoids×Section tacamahaca were selected to identify the cold resistance by investigating on the changes of physiological indexes under different temperature. In addition, effects of Calcium signal system on the cold resistance physiological mechanisms were investigated. The main results were as followed:1. According to the comparison of dehydration rate, LT50, MDA and soluble protein contents, SOD and POD activities, the results showed that there were obvious cold resistance differences among those hybrid clones. The sequence of cold resistance in nine hybrid clones was as follows: 07-69 × P.cathayana 1 > 06-69 × P.purdomii 1 > 06-57 × P.szechuanica 1 > Zhongsui 12 > 07-Westda-zhai × P.purdomii 1 > Shaanxi NO.4 > 08-69 × P.cathayana 2 > 08-69 × P.cathayana 4 > E24-01. 07-69 × P.cathayana 1 showed the best cold resistance to cold stress of all the hybrid materials, which belonged to the cold resistance clone. The E24-01 clone material showed the worst resistance to cold stress. The differences of LT50 among the nine hybrid clones were obvious, and it would provided a theoretically support for the breeding of poplar.2. Compared to others clone materials, the hybrid material of 07-69×P.cathayana 1 showed a better adaptability for low temperature stress which prepared lower dehydration rate, LT50, MDA content and higher SOD activity, POD activity, soluble protein content. The change trend of the SOD activity, POD activity and soluble protein content were basically same to the change of temperature, while the content of MDA had a curve just like a converse ‘S’ in terms of its content.3. Based on the effect of different Ca2+ concentration on cold resistance in hybrids of Shaanlin NO.4 and 07-69 × P.cathayana 1 under low temperature stress, we found that 5~15mmol/L Ca2+ treatment could significantly strengthen the cold resistance of poplar compared to higher Ca2+ treatment, 10 mmol/L Ca2+ treatment could extermely decrease membrane injury rate and MDA content, while increase SOD and POD activities and soluble protein content. Exogenous Ca2+ could effectively improve the cold resistance of poplar seedlings and alleviate the damage caused by low temperature stress.4. By addition of Ca2+ chelating agent EGTA or calmodulin antagonist TFP on Shaanlin NO.4 and 07-69 × P.cathayana 1, internal exogenous calcium could strengthen the cold resistance of poplar compared to the Ca-deficient treatment. However, the mechanism of adjusition to the cold stress was inhibited. Consequently, it is suggested that the calcium signal system may be involved in the membrane lipid peroxidation, protective enzyme system and osmotic system in hybrids of Shaanlin NO.4 and 07-69 × P.cathayana 1 under low temperature.5. According to the research on the cold resistance in the hybrid of Shaanlin NO.4 under calcium salts treatment(Ca(NO3)2, CaCl2, Ca(Ac)2), the results showed that calcium salts treatment could effectively decrease membrane injury rate, LT50 and the accumulation of MDA, increase the activities of antioxidant enzyme and the content of osmotic substances, enhance the cold resistance of poplar and alleviate the damage caused by low temperature stress. The ability of cold resistance was been improved under different type of calcium salts, the sequence was as follows: CaCl2 > Ca(NO3)2 > Ca(Ac)2.更多还原