白桦响应盐胁迫的生理学机制及相关基因的鉴定

Birches belong to the genus Betula in the family Betulaceae. Birch trees arefast-growing woody plants that adapt to adverse environments, and are widely distributedfrom north Europe to Russia, north of China, and Japan. Therefore, it is important tostudy the mechanism of salt stress tolerance in birch plants. Recently, the sequencingwhole-genome of Betula platyphylla Suk. has been completed. Therefore, it has laid asolid foundation for studying the Betula platyphylla Suk’s genetic resources. Here, we treated birch seedlings with a solution of 100 mM NaCl and studied thephysiological and related molecular response of white birch (Betula Platyphylla Suk.) tosalt stress. We found that abscisic acid and Ca2+level were induced in birch during theearly salt stress period, ABA was induced during early salt stress period, and thendecreased, and Ca2+level increased slowly but maintained at a high level for a long time. Under salt conditions, photosynthetic activity was inhibited; the Salt-Overly-Sensitive(SOS) pathway was activated in birch roots; reactive oxygen species (ROS) wasaccumulated, and superoxide dismutase is the main ROS scavenger in roots, whileperoxidase is the main ROS scavenger in leaves. Proline plays a role in stress tolerance inboth roots and leaves; however, soluble sugars and trehalose also have roles in salt stresstolerance, mainly in leaves. Additionally, the genes that might have essential roles incontrolling some of these physiological changes were identified. In leaves, the POD5 andPOD8 genes might play a main role in increase the POD activity. In roots, the SOD1 andSOD4 genes might make main contributions to the increased SOD activity during saltstress. P5CS1 is closely related to the biosynthesis of proline in roots, and P5CS2 mightplay a main role in proline biosynthesis in leaves; the TPS4 and TPP3 genes might playimportant roles in the biosynthesis of trehalose in birch during salt stress period. Therefore, they represent good candidate genes to characterize the salt tolerancemechanism of birch and to breed stress tolerant plants. Late Embryogenesis Abundant (LEA) proteins are accumulated during the last period of seed development, and also play important roles in abiotic stress tolerance of plants. Inthe present study, we studied the 13 LEA genes that are highly similar with the stresstolerance LEA genes in Arabidopsis, and they were cloned from B. platyphylla. Inaddition, the LEA genes that are in response to salt stress were further identified usingqRT-PCR. These LEA genes involving in salt stress response will be the good candidategenes in genetic approaches for breeding salt stress tolerance in plants

新疆沙漠桑持水力的筛选研究

为获得生长在沙漠深处不同类型桑树基因资源的持水力差异信息,采用自然脱水法,对黑桑、白桑、粉桑和雄桑等不同类型的20份沙漠桑基因资源的失水过程进行了测定;研究结果表明,沙漠桑树分为强持水型、中等持水型和弱持水型,黑桑、白桑和粉桑类型桑树的持水能力较雄桑类型桑树强;根据枝条、叶片等同器官持水能力强弱不同,多数沙漠桑叶片的持水能力不太强,初步认为枝条的持水能力较叶片强

新疆沙漠桑树品种持水力研究初报

持水力是表征植物耐旱性的一个重要指标。本文以新疆当家现行桑品种——新桑1号为对照,以测定桑树中上部叶片每1h失水量的方式,对抗干旱性强的沙漠桑树品种——策沙1号失水过程进行了监测。初步的研究结果表明,策沙1号叶片持水力比新桑1号强,可以确定其为荒漠植物中持水型较强的桑属品种

新疆沙漠桑树光合特性日变化的研究

沙漠桑树净光合速率的日变化在强光、高温、干燥的晴天呈双峰曲线,沙漠桑树的净光合速率和气孔导度较低,沙漠桑树的光合速率与气孔导度呈极显著相关关系,光合作用受叶片内部气孔活动状态、蒸腾速率和外界空气温度、空气相对湿度等因子的影响