Effects of NaCl and NaHCO3 Stress on Photosynthesis and Chlorophyll Fluorescence Characteristics of Hemerocallis fulva ‘Golden Doll’

With Hemerocallis fulva‘Golden Doll'as an experimental material,the effects of different concentrations of neutral salt( NaCl) and alkaline salt( NaHCO3) stresses on photosynthesis and chlorophyll fluorescence characteristics in H. fulva seedlings were studied. The results showed that salt stress treatment significantly reduced the photosynthetic capacity of H. fulva. Under the NaCl and NaHCO3 stresses,the photosynthetic characteristics and chlorophyll fluorescence parameters of H. fulva seedlings were basically the same,but the photosynthetic characteristics and chlorophyll fluorescence parameter values of H. fulva seedlings were significantly different under different salt types and salt concentrations. With the extension of days of salt stress and the increase of salt concentration,the initial fluorescence yield( Fo) and non-photochemical quenching coefficient( NPQ) increased;the maximum fluorescence yield( Fm),maximum photochemical efficiency( Fv/Fm),PSII actual photosynthetic quantum yield( Y) and apparent quantum efficiency( AQY) all showed a downward trend;and moreover,with the extension of days of salt stress and the increase of salt concentration,the net photosynthetic rate( Pn) decreased and the intercellular CO2 concentration( Ci) increased. It was speculated that under salt stress,the photosynthetic characteristics of H. fulva leaves were inhibited. On the one hand,the non-stomatal limiting factor,i. e.,the chlorophyll content decreased,which led to the inhibition of photosynthetic characteristics. On the other hand,the decrease in the photosynthetic performance of mesophyll cells led to a decrease in the net photosynthetic rate of H. fulva. The changes of photosynthetic characteristics and chlorophyll fluorescence parameters in H. fulva caused by salt stress were closely related to the types of salts and salt concentration. High salt stress significantly inhibited the photosynthetic capacity of H. fulva‘Golden Doll',and the effect of NaHCO3 on H. fulva seedlings was significantly greater than that of NaCl.

秦岭南麓萱草属植物种质资源遗传多样性的RAPD分析

为了探明秦岭南麓萱草属种质资源的现状,以秦岭不同生境23份野生萱草(Hemerocallis fulva L.)资源和黄花菜栽培种‘沙苑花’为试材,采用RAPD技术,从35条随机引物中筛选出11条多态性好的引物对24份萱草种质材料进行遗传多样性分析。结果显示,24份样本共获得492个扩增位点,其中多态性条带446个,占90.7%,各样本的多态性比率从80.0%到96.9%。遗传距离矩阵和UPGMA聚类分析显示,24份材料之间遗传距离为0.00~0.69,在0.65阈值时可将24份材料分为3大类,其中23号黄花菜野生种聚为一类,黄色花,24号黄花菜栽培品种‘沙苑花’聚为一类,花也呈黄色,其他采样地的野生萱草样本聚为一类,花色从橘黄至橘红色;花径大小、株高等特征与样地的生境间未表现出明显规律,生物学性状变化差异较大。总体来看,秦岭分布的萱草属植物在种间或种内均存在丰富的遗传多样性,也表现出聚类分析结果与种质资源地理分布间的不一致性,该结果对中国萱草属植物及其他地被植物种质资源的收集、保存和育种工作具有一定的借鉴意义。

生物炭和枯草芽孢杆菌对Cd污染土壤中萱草生长和土壤修复的影响

本研究旨在探讨生物炭和枯草芽孢杆菌对Cd污染土壤中大花萱草生长和土壤修复的影响。研究设置了四个处理组:(1)对照组(CK),不添加任何改良剂;(2)生物炭组(B),土壤添加3%生物炭;(3)枯草芽孢杆菌组(BS),土壤添加4×10~9CFU/kg土壤的枯草芽孢杆菌悬液;(4)生物炭+枯草芽孢杆菌组(B+BS),土壤同时添加3%生物炭和4×10~9CFU/kg土壤的枯草芽孢杆菌悬液。分别测定了各组大花萱草的农艺性状、净光合速率、蒸腾速率、生理指标、土壤p H、大花萱草中Cd含量以及土壤中有效态Cd含量。研究结果显示,相较于B组和BS组,B+BS组的大花萱草株高、叶面积、地上生物量和地下生物量显著增加(P<0.05)。与B组和BS组比较,B+BS组的净光合速率和蒸腾速率显著增加(P<0.05)。相较于B组和BS组,B+BS组的大花萱草含水量和叶绿素含量显著增加,而细胞膜透性、游离脯氨酸含量和可溶性糖含量显著降低(P<0.05)。与B组和BS组比较,B+BS组的土壤p H值显著增加(P<0.05)。与B组和BS组比较,B+BS组的大花萱草Cd含量和土壤中有效态Cd含量均显著降低(P<0.05)。综上所述,本研究表明,生物炭和枯草芽孢杆菌均能有效促进Cd污染土壤中大花萱草的生长,促进土壤修复,并且两者联用的效果最佳。

基于叶面温度和抗旱性评价等级的耐干旱萱草品种筛选方法的建立

中国干旱和半干旱地区面积较广大,选育耐干旱品种是当前包括萱草在内的园艺植物育种的重要目标之一。实验通过叶片表面温度测定的方法初步筛选,进而通过测定气孔导度、气孔密度、离体叶片失水率和相对含水量等耐干旱指标,并观察干旱处理及复水后的萱草地上部分外观形态,进行了抗旱性分级,建立了一套萱草耐干旱品种简单、快速的筛选方法。相关性分析表明萱草叶面温度与抗旱性呈正相关,本研究为从萱草引种或杂交后代群体中快速筛选耐旱萱草品种提供参考。