镉胁迫对金丝垂柳幼苗生长及叶绿素荧光特性的影响

采用盆栽试验的方法,研究土壤中不同浓度的镉(0、2、20、80 mg·kg-1)胁迫条件对金丝垂柳幼苗的生长、净光合速率(Pn)、光合色素含量及叶绿素荧光参数（Fv/Fm、φPsⅡ和qP）的影响.结果表明:(1)2 mg·kg-1处理组植物的生长、净光合速率及叶绿素荧光参数随着处理时间的增加呈先下降后上升的趋势,说明2...     

模拟淹水对杞柳生长和光合特性的影响

以1年生红皮柳(Salix integra cv.hongpi)和青皮柳(Salix integra cv.qingpi)为试验材料,研究了人工模拟淹水胁迫对两个杞柳品种的生长、气体交换及叶绿素荧光的影响.经过75d的淹水处理,两个品种的存活率均为100％.在试验过程中,红皮柳和青皮柳都产生了有利于吸收氧气的不定根和肥大的皮孔,但在产生的时间上红皮柳较青皮柳迟lOd左右.渍水处理促进了青皮柳的生长和光合作用,而红皮柳在渍水和轻度淹水胁迫处理下的生长、叶绿素含量(Chl)、净光合速率(PN)和气孔导度(Gs)都明显低于对照.随着淹水时间的增加,红皮柳的非光化学淬灭系数(NPQ)持续增加并高于对照,最大光化学量子效率(Fv/Fm)持续下降且明显低于对照;青皮柳的非光化学淬灭的值增加幅度较小,最大光化学量子效率一直在0.8-0.85之间波动,与对照相比都无显著差异.以上的实验结果表明在淹水胁迫下红皮柳的光合运转机构受到了一定程度的损伤,而渍水处理则促进了大青皮的生长,因此青皮柳较红皮柳而言更耐淹,更适合在河岸带和消落区生长.     

Accumulation and effects of sulfadimethoxine in Salix fragilis L. plants: a preliminary study to phytoremediation purposes

The application of manure to fertilize arable lands is one of the major means through which veterinary sulfonamides (SAs) enter the environment. Little is known about the capacity of woody plants to phytoremediate this class of antibiotics. To this purpose we performed preliminary studies to evaluate Salix fragilis L. response to sulfadimethoxine (SDM) by investigating both its ability to absorb and tolerate doses of SDM found in fresh faeces of treated calves. Forty cuttings were exposed to either 0, 0.5, 1, or 2 mM of SDM for one month. Decreases in photosynthetic electron transport rate and net CO2 assimilation after 25 days for the higher SDM concentrations were noticed. Moreover, alterations in root morphology of treated plants were observed and further investigated through electron microscopy. However, collected data revealed high root accumulation potential. These preliminary results are promising as they demonstrate that Salix fragilis L. can both absorb and tolerate high concentrations of SAs.     

Lack of influence of photoperiod on the metabolism of gibberellin A20 in Salix pentandra

The influence of photoperiod on the metabolism of GA₂₀ in Salix pentandra was studied by feeding [³H]-GA₂₀ to seedlings which had been grown previously under long day (LD) or short day (SD) conditions. After 48 h in LD or SD, metabolites were separated on sequential, silica gel partition columns and reversed-phase C₁₈ HPLC. The principal metabolite co-chromatographed with [³H]-GA₁ and this conversion was confirmed by feeding [²H]-GA₂₀, which was converted to [²H]-GA₁ as identified by gas chromatography-selected ion monitoring. Chromatographic evidence also indicated the minor conversion of [³H]-GA₂₀ to [³H]-GA₈ (via [³H]-GA₁) and trace conversion to [³H]-GA₂₉ (GAs A_1.8,20.29 are native in Salix). Ethyl acetate-insoluble [³H] metabolites were formed and could be cleaved by cellulase to release putative [³H]-GA₂₀ and [³H]-GA₁ suggesting the conversion to glucosyl conjugates of these GAs. Metabolism of [³H]-GA₂₀ was slightly more rapid in plants previously grown under LD than SD, an effect which reflected the generally increased shoot growth under LD. However, altering the photoperiod after [³H]-GA₂₀ addition had only a slight effect on the metabolism of [³H]-GA₂₀ in Salix seedlings. This indicates that the conversion of GA₂₀ to GA₁ is not a controlling step in the photoperiodic regulation of growth cessation in Salix.     

Cadmium and copper uptake and translocation in five willow (Salix L.) species

The efficacy for phytoremediation of five willow species was tested by experimental copper and cadmium uptake in a greenhouse hydroponic system. Five treatments included two concentrations (5 and 25 microM for each metal) and a control. Metal concentrations in solution as well as solution uptake were monitored. Metal resistance was assessed through effects on the dry weight of roots and shoots. The willow species tested were generally resistant of increased Cu and Cd content. Metal accumulation was found in all plant organs of all species. Growth and transpiration were not decreased by 5 microM of copper and 25 microM of cadmium in the solution for most species. 25 microM copper caused injury and reduced the dry weight for all species after 21 d. Salix nigra was highly resistant of both Cu and Cd and accumulated more metals than other species. Future field study should be conducted to confirm the findings and feasibility of the phytoremediation technology using those species.     

Are heat and cold resistance of arctic species affected by successive extreme temperature events?

Extreme temperature events are projected to increase in frequency in a future climate. As successive extremes could occur more frequently, patches of vulnerable tundra vegetation were exposed to two consecutive heat waves (HWs) of 10 d each, with a 5-d recovery period in between. Surface temperatures during the HWs were increased approximately 6 degrees C using infrared irradiation sources. In three of the four target species (Pyrola grandiflora, Polygonum viviparum and Carex bigelowii), plant conditions improved upon the first exposure. Depending on species, leaf relative growth, leaf chlorophyll content or maximal photochemical efficiency was increased. In P. grandiflora the positive effects of the heat on the photosynthetic apparatus led to augmented net photosynthesis. By contrast, Salix arctica responded mainly negatively, indicating species-specific responses. During the second HW, leaf mortality suddenly increased, indicating that the heat stress induced by the extreme events lasted too long and negatively influenced the species resistance to high temperature. After the HWs, when plants were exposed to (low) ambient temperatures again, plant performance deteriorated further, indicating possible loss of cold resistance.     

Effect of rootstock on photoperiodic control of elongation growth in grafted ecotypes of Salix

Scions of a southern (59° 40'N Lat.) and a northern (69° 39'N Lat.) ecotype of Salix pentandra L. were grafted on clonal rootstocks of the same ecotypes. Effects of photoperiod on elongation growth of the 4 combinations (south/south, south/north, north/south and north/north) were studied in a phytotron at 18° and 15°C. The photoperiodic response was primarily dependent on the ecotype of the scion, but this response was significantly modified by the rootstock. Cessation of apical growth was advanced by a northern clone and delayed by a southern clone as a rootstock. The results indicate that the critical photoperiod for cessation of apical growth could be slightly decreased by a northern and increased by a southern rootstock.     

两个葡萄杂交后代根系抗葡萄根瘤蚜及抗寒性鉴定

【目的】为了筛选抗葡萄根瘤蚜Daktulosphaira vitifoliae Fitch且抗寒的葡萄砧木以适应我国葡萄生产需求。【方法】以山葡萄Vitis amurensis Rupr.左山1号×SO4杂种F₁代的45个株系（A系列）和左山1号×101-1杂种F₁代27个株系（B系列）为试材;采用离体根接种鉴定法进行抗葡萄根瘤蚜鉴定及抗性分级;采用差热分析系统（differential thermal analysis; DTA）进行各株系根系的低温放热（low temperature exotherms; LTE）分析;建立各株系根系韧皮部及木质部的温度-伤害度(LT-I)回归方程;评估各株系根系的抗寒性。【结果】葡萄根瘤蚜在杂交株系根系上的产卵量均显著低于敏感品种巨峰;筛选出被葡萄根瘤蚜侵染后不能形成根瘤;抗葡萄根瘤蚜级别为0级的A系列杂交株系18个和B系列株系11个。被葡萄根瘤蚜侵染后形成根瘤比例低于10%的抗葡萄根瘤蚜级别为1级的A系列杂交株系9个和B系列株系4个;筛选出A系列综合低温放热温度隶属度函数、韧皮部和木质部低温放热温度隶属度函数3个指标均低于贝达的株系27个;B系列各指标均低于贝达的株系3个。【结论】本研究筛选出抗寒性强且对葡萄根瘤蚜抗性强的A系列株系15个和B系列株系2个。其中;A14; A16; A18; A22; A23; A28; A34; A35; A38; A44; A50; B24和B26对葡萄根瘤蚜抗性级别为0; A11; A15; A17和A27对葡萄根瘤蚜抗性级别为1。     

HPLC-MS/MS analysis of willow bark extracts contained in pharmaceutical preparations

Preparations containing willow bark extract are popular herbal remedies, but they are mostly standardised with respect to only one compound (usually salicin). RP-HPLC using a C18-column eluted with water:methanol:tetrahydrofuran and coupled to electrospray triple-quadrupole MS and MS/MS was used for the characterisation of dried extracts of Salix spp. and for the identification of their constituents. Comparison with reference substances led to the identification of 13 compounds (saligenin, salicylic acid, salicin, isosalicin, picein, salidroside, triandrin, salicoylsalicin, salicortin, isosalipurposide, salipurposide, naringenin-7-O-glucoside and tremulacin). Two pharmaceutical preparations containing willow bark extract, used in clinical trials and labelled Salix daphnoides and S. purpurea x daphnoides extracts, were compared using the described method and exhibited several clear differences, the most prominent of which was the possible presence of picein in the former preparation. The described method may be utilised for the characterisation of herbal medicines in order to ensure comparability of medication in further clinical trials.     

Heat shock proteins in willow (Salix viminalis)

The heat shock response in three vegetatively propagated clones of Salix viminalis L. was studied. In the clone 78198, synthesis of a total of 58 proteins was induced or increased by heat shock. Of these proteins, 39 were found in both leaves and callus, 8 only in leaves, and 11 only in callus. The number of heat shock proteins differed between the three clones studied. The molecular weights of the heat shock proteins ranged from 18000 to over 94000. The optimal synthesis of heat shock proteins took place at 37–40°C, but several proteins could be induced at 25–30°C. The synthesis of the majority of the proteins present at a normal growth temperature (20°C) was not completely blocked by the heat shock. More than 12 h was needed for the reappearance of the normal protein synthesis pattern after heat shock.