荒漠地区柽柳人工固沙林土壤水分动态研究

柽柳林土壤剖面的含水量与裸沙地土壤含水量的变化趋势有相似性,表层（0－30cm)含水量均受蒸发量和降雨量的影响变化较大,由于树冠的遮荫作用林地该层平均含水量高于裸沙地的含水量,30－200cm范围内林地土壤的各测量层平均含水量较裸沙地的低,林地和裸沙地土壤含水量均值随深度的变化可用二次函数描述;降雨对每月的0－200cm的土壤水量没有明显的影响,说明降雨多数在当月就被蒸散和深层渗漏所消耗;发现柽柳人工固沙林能在沙土壤的0－200cm范围内有较低的含水量条件下生存。     

温州裂叶月见草入侵群落和土壤种子库种类组成的季节动态

通过野外调查和萌发实验,研究了浙江温州地区裂叶月见草(Oenothera laciniata)入侵群落和土壤种子库种类组成的季节动态,结果表明:裂叶月见草土壤种子库中共有种子植物46种,种子库各层储昔与物种数量不同,呈现为上层(0～2 cm)>中层(2～5 cm)>下层(5～10 cm),层间差异较明显;裂叶月见草入侵群落地上植被与土壤种子库群落组成相似性系数为0.632,表明该群落裂叶月见草入侵时间不长,处在演替的初期阶段;裂叶月见草种子具有休眠特性,并在萌发的过程中阶段性破除休眠;裂叶月见草的重要值与群落的物种多样性存在着正相关性,但未达显著水平(P>0.05);在每年的11月至次年4月裂叶月见草营养生长期铲除是控制裂叶月见草传播和扩散的有利时机.     

万年蒿多糖的含量测定

用水提醇沉法提取万年蒿多糖,用硫酸-苯酚法测定含量,结果多糖含量为22.45%.     

Hawkmoth and bee pollinators impact pollen dispersal at the landscape but not local scales in two species of Oenothera

Premise

Animal pollinators play an important role in pollen dispersal. Here, we assessed differences in pollen and seed dispersal and the role of pollinator functional groups with different foraging behaviors in generating patterns of genetic diversity over similar geographic ranges for two closely related taxa. We focused on two members of Oenothera section Calylophus (Onagraceae) that co-occur on gypsum outcrops throughout the northern Chihuahuan Desert but differ in floral phenotype and primary pollinator: Oenothera gayleana (bee) and O. hartwegii subsp. filifolia (hawkmoth).

Methods

We measured breeding system and floral traits and studied gene flow and population differentiation at the local (<13 km; four populations) and landscape (60–440 km; five populations) scales using 10–11 nuclear (pollen dispersal) and three plastid (seed dispersal) microsatellite markers.

Results

Both taxa were self-incompatible and floral traits were consistent with expectations for different pollinators. Seed and pollen dispersal patterns were distinctly different for both species. We found no evidence of genetic structure at the local scale but did at the landscape scale; O. gayleana showed greater differentiation and significant isolation by distance than in O. hartwegii subsp. filifolia. The plastid data were consistent with gravity dispersal of seeds and suggest that pollen dispersal is the principal driver of genetic structure in both species.

Conclusions

We demonstrated that pollinator functional groups can impact genetic differentiation in different and predictable ways. Hawkmoths, with larger foraging distances, can maintain gene flow across greater spatial scales than bees.

     

Effects of Oenothera biennis L. and Hypericum perforatum L. extracts on some central nervous system myelin proteins,brain histopathology and oxidative stress in mice with experimental autoimmune encephalomyelitis

We investigated the effects of Oenothera biennis L. and Hypericum perforatum L. extracts on brain tissue histopathology, myelin oligodendrocyte glycoprotein (MOG), myelin basic protein (MBP), total antioxidant status (TAS), total oxidant status (TOS) and oxidative stress index (OSI) in mice with experimental autoimmune encephalomyelitis (EAE). Forty-seven C57BL/6J mice were divided into the following groups: multiple sclerosis (MS), control (healthy mice), MS + H. perforatum treated (MS + HP), MS + O. biennis treated (MS + OB). All groups except the control group were immunized by EAE methods. Two weeks after the immunization, the mice in the MS + HP group were fed normal food containing 18 ? 21 g/kg H. perforatum extract, the mice in MS + OB group were fed normal food containing 18 ? 21 g/kg O. biennis extract, and the mice in control and MS groups were fed normal food for six weeks. Brain tissue samples were collected from all mice for histopathological and biochemical analysis. Clinical signs of the disease were scored using functional systems scores (FSS) daily. The H. perforatum and O. biennis extracts ameliorated the increased brain tissue MOG and MBP values for animals with MS. H. perforatum and O. biennis extract decreased the TOS and OSI values for brain tissue and increased TAS levels in brain tissue of animals with MS. In addition, H. perforatum and O. biennis extracts decreased the clinical signs at the end of the experiment compared to the beginning of extract administration. We found that myelin was lost in MS group vs. control group. H. perforatum and O. biennis extract treatments decreased the amount of myelin loss in the MS + HP and MS + OB groups. We also observed amyloid deposition on vascular walls, in the cytoplasm of the neurons and in the intercellular space in the MS group. O. biennis and H. perforatum treated groups exhibited neither abnormal amyloid deposition nor obvious cell infiltration. The beneficial effects of O. biennis and H. perforatum for attenuating myelin loss and amyloid deposition suggest their therapeutic utility for treatment of MS.     

The Complex-Heterozygotes of Oenothera grandiflora L'Her.

Complex-heterozygotes discovered in populations of O. grandiflora in Alabama are composed of a typical grandiflora (B) complex and an altered B complex which modifies the phenotype in the direction of O. villosa (A). A cytogenetic analysis of the new complex, designated B^A, is reported including results of its compatibility with different plastomes. The evidence suggests that the B^A complex resulted from hybridization between O. grandiflora and the pollen complex of the sympatric O. biennis.     

A reduction in the abundance of calium oxalate crystals in Oenothera improves the yield of intact chloroplasts

Abstract. Oenothera plants grown as shoot meristem cultures on media having a low calcium concentration had a reduced abundance of raphides when compared to greenhouse-grown plants or shoot meristem cultures grown on higher concentrations of calcium. Plants from the low-calcium media also yielded a higher proportion of intact chloroplasts during subcellular fractionation.