辽西北风沙地区不同无性系桑树抗旱性

Drought resistance of different Morus alba L clones in sandstorm area of northwest Liaoning Province

为选育适合辽西北风沙地区生长的优良桑树品种,以沈阳农业大学选育的"沈桑1号"(SS)、辽宁省阜新市彰武县优株(ZW)、吉林省通化市集安县桑树优株(JS)3种优质桑树无性系以及东北主栽品种"龙桑1号"(LS)为试验材料,通过测定不同无性系桑树在干旱胁迫下的叶片光合色素含量、光响应曲线、不同光强对气体交换参数的影响以及光系统Ⅱ(PSⅡ)的变化,研究不同无性系桑树的抗旱性。研究发现,在干旱胁迫下,JS和SS的光合色素含量降幅较大,LS其次,ZW的光合色素含量变化不明显。干旱胁迫致使桑树无性系的净光合速率降低,气孔导度、胞间CO;浓度和蒸腾速率也出现不同程度的下降,水分利用效率上升,且ZW、LS、JS和SS的光响应曲线的特征参数下降幅度依次增加。干旱胁迫破坏了桑树无性系PSⅡ反应中心的活性,使电子传递受到抑制,导致QA;累积,光合机构受损。综合比较干旱条件下4种无性系的各项参数,ZW受干旱胁迫的影响最小,其次是LS,而JS和SS在干旱胁迫下,光合能力表现较差。综上,ZW的抗旱能力整体来说最强,更适合在辽西北风沙地区种植推广。

In order to select excellent Morus alba L. varieties suitable for the windy and sandy area of northwestern Liaoning, three Morus alba clones, “Shensang No. 1” selected by Shenyang Agricultural University(SS), Morus alba superior clone in Zhangwu County, Fuxin City, Liaoning Province(ZW) and Morus alba superior clone from Ji’an County, Tonghua City, Jilin Province(JS), and “Longsang No. 1”, the main cultivar in Northeast China(LS), were used as test materials. The drought resistance of different Morus alba clones was studied by measuring photosynthetic pigment content, light response curve, the influence of light intensity on gas exchange parameters and the change of photosystem Ⅱ(PSⅡ) under drought stress. Under drought stress, photosynthetic pigment content of all clones decreased, with ZW changing the least, followed by LS, and JS and SS decreasing greatly. Under drought stress, the net photosynthetic rate of Morus alba clones decreased, stomatal conductance, intercellular CO;concentration and transpiration rate decreased to varying degrees, while water use efficiency increased. The reduction of parameters of light response curves strengthened with the order of ZW, LS, JS and SS. Drought stress destroyed the activity of PSⅡ reaction center of Morus alba clones, inhibited electron transfer, leading to QA;accumulation and photosynthetic apparatus damage. Comparing the parameters of four clones under drought conditions, ZW was least affected by drought stress, followed by LS, while JS and SS had poor photosynthetic capacity. Collectively, ZW has the strongest drought resistance, which would be more suitable for planting and cultivating in the windy and sandy area of northwestern Liaoning.