Projecting the potential distribution and analyzing the bioclimatic factors of four Rhododendron subsect.Tsutsusi species under climate warming

Tsutsusi is one of the eight subgenera of the Rhododendron genus.Four Tsutsusi species,R.indicum,R.simisii,R.oldhamii,and R.schlippenbachii,have high ornamental and medicinal values,resulting in an increasing market demand.These species thrive in cool and humid environments and are widely distributed in Europe and Asia.Whether global climate warming will affect the distribution of these valuable resources remains unclear.Thus,this study analyzed the climatic suitability of these species for the first time on the basis of 1552 geographical distribution points and 19 bioclimatic factors using the maximum entropy model.The results show that a suitable distribution area for all four species would decrease under climate warming.The main bioclimatic factors affecting their distribution are the mean temperature of the coldest quarter for R.indicum,the mean diurnal range for R.simisii,and precipitation of the warmest quarter for R.oldhamii and R.schlippenbachii.In addition,the contribution of the temperature-related bioclimatic factors to the distribution of R.indicum and R.simisii is higher than that of the associated precipitation-related climatic factors;in contrast,the contribution of precipitation-related bioclimatic factors to the distribution of R.oldhamii and R.schlippenbachii is higher than that of the temperature-related climatic factors.These results provide references for the introduction,conservation,sustainable development,and utilization of these four species in the future,and may also provide information with regards to other Rhododendron species.

大字杜鹃离体快繁体系建立及种质试管保存研究

以大字杜鹃新生嫩芽为外植体,应用均匀设计法筛选其最适合的嫩芽基部直接再生芽苗、生根及种质试管保存的培养基,结果表明,最适合的基部直接再生芽苗诱导培养基为:DR+2-ip3.00mg·L-1,诱导率达95.5%以上;生根培养基:MS(改良)+IAA 0.50mg·L-1+IBA 0.10mg·L-1+KT 0.10mg·L-1,生根率达99%以上;试管保存培养基:N-68+B92.30mg·L-1+根皮苷1.50mg·L-1,保存时间可达30个月以上。以再生植株的茎节为材料进行快繁的结果表明,在28d的一个培养周期内增殖倍数平均达65以上。常温条件下,采取"矮化延缓生长"的方法在试管内保存种质资源,建立了大字杜鹃的离体培养和种质试管保存体系。

牡丹江地区大字杜鹃引种研究

[目的]驯化大字杜鹃(Rhododendron schlippenbachii Maxim.),使其适应黑龙江省东南部地区露地栽培,为园林应用提供新品种。[方法]引种大字杜鹃进行露地栽培试验,研究喷施生根粉、遮阴、覆盖松针土3种方法的影响。[结果]喷施ABT生根粉对大字杜鹃生长促进作用显著;在高温天气下,选择遮阴率为50%的遮阴网遮阴,或在土壤表面覆盖5 cm厚的松针土较均适宜大字杜鹃的生长。[结论]该研究可为大字杜鹃在黑龙江东南部地区的引种栽培提供科学依据。

大字杜鹃扦插繁殖技术的研究

以延边朝鲜族自治州珲春市敬信乡野生大字杜鹃为材料,研究扦插插条的选取时期、插条形态、基质、生长调节剂的种类和浓度及浸泡时间等对扦插插条生存率的影响.结果表明,扦插时期以春、秋季为最佳,扦插基质以蛭石∶草炭土=1∶1为宜,以有顶芽的插条在200 mg/L IBA+100 mg/L NAA中浸泡5 s的处理获得较高的扦插插条生根率.

大字杜鹃播种育苗技术研究

以大字杜鹃为材料,对播种育苗技术进行研究,结果表明,种子发芽适宜的光照强度为1 0002 000 Lx;种子最佳催芽处理方法是：种子采集调制后冷藏,播种前浸泡48 h;最适宜的播种基质为腐殖土＋土沙混合,比例为2 1,再覆盖1 cm厚粉碎的苔藓。播种育苗适宜在温室与塑料大棚中进行,出苗率分别达到85%和61%,当年苗高7.5 cm,地径2.8 mm,不适于露地播种。

北方野生杜鹃花驯化培育技术

北方野生迎红杜鹃、大字杜鹃观赏价值较高,具有极强的抗寒性,能耐-30。C左右的低温,但北方一直没有引种下山驯化栽培。迎红杜鹃、大字杜鹃通过播种方法大量繁殖,驯化培育,能够促进北方露地越冬杜鹃推广种植,前景广阔。