Pre-and post-pollination barriers between two exotic and five native Sagittaria species:Implications for species conservation

Anthropogenic introduction of species has resulted in a breakdown of geographical barriers and hybridization in previously allopatric species.Thus,examining hybridization proneness of exotic species contributes to revealing its potential threat.Moreover,reproductive barriers may be strengthened or weakened due to long-term geographical isolation for these newly sympatric species.However,few studies have evaluated multiple barriers between alien and native species.In this study,we quantified the importance of four pre-pollination barriers(phenological,floral traits,pollen production,and floral constancy)and four post-pollination barriers(pollen-pistil incompatibility,seed set,seed viability,and seedling survival)between two introduced and five native Sagittaria species.Results showed that introduced S.platyphylla was cross-compatible with two native species,whereas introduced S.montevidensis was incapable of hybridizing with any native species.Different barriers were asymmetric within species pairs and multiple barriers acted in concert to maintain species boundaries.Postpollination barriers contributed more to total reproductive isolation in native species,whereas prepollination barriers played a stronger role in total reproductive isolation for two introduced species.Seed set was the only barrier that was positively correlated with genetic distance.Our results provide a perspective to better understand reproductive barriers for secondary contact species.We highlight the importance of monitoring hybridization events before human introduction and the possible conservation strategies to remove invasive species with hybridization proneness.

Sex Expression and the Evolutionary Advantages of Male Flowers in an Andromonoecious Species, Sagittaria guyanensis subsp. lappula (Alismataceae)

Sex expression in Sagittaria guyanensis H.B.K. subsp. lappula (D. Don) Bojin is typically andromonoecious while the other species in the same genus are basically monoecious. The evolutionary advantages of male flowers and hermaphrodite flowers in S. guyanensis subsp. lappula were assessed by measuring sex allocation and pollen movements in two wild populations of the species. Two cultivated populations served as controls. The percentage of male flowers was very low in the two wild populations in Dongxiang, Jiangxi Province and Wuyishan, Fujian Province, viz., 2.48% and 0.96% respectively. In the two cultivated populations, male flower percentage significantly increased when the soil was of higher nutrient content. This indicates that the allocation to male versus female reproduction might change in response to environmental factors. Pollen production per male flower was 4.1 times higher than that of a hermaphrodite flower. The floral shape and size of male and hermaphrodite flowers were similar. No difference was observed between these dimorphological flowers in pollen germination rate in vitro and in the speed of pollen tube growth in vivo . Anthesis was only 4-5 h. Male flowers usually opened 0.5 h earlier than hermaphrodite flowers. An unexpected finding was that no pollen from the male flowers was found on the stigmas of the hermaphrodite flowers, in spite of the occasional visits by insects to both types of flowers in both wild and control populations. A consistent pattern of fruit development was found to exist in open pollinated flowers as well as in flowers that had been bagged. The sex ratios did not have significant influence on fruit set. Approximately 25% of the pistils in a gynoecium failed to develop into fruits because no pollen was deposited on them, indicating that the fruit set of this andromonoecious plant is mainly affected by pollen limitation rather than resource limitation. Reproduction in S. guyanensis subsp. lappula in the habitats was dependent on self_pollination in hermaphrodite flowers. The male flowers in this species might be a potential source of additional pollination and may facilitate cross_pollination. The fact that the flowers of monoecious species in Sagittaria pollinated by a wide diversity of insect visitors may contribute enormously to the diversification of sex expression in this genus.

A Preliminary Study on the Tissue Culture of Sagittaria trifolia L.

[Objective] This study was to optimize the experimental conditions for large scale propagation of Sagittaria trifolia L via tissue culture.[Method] The dominant S.trifolia cultivar Baoyingziyuan introduced from Jiangsu Province was used as experimental material to study the impacts of various culture conditions on tissue culture of its stem tips and induction of stolons.[Result] Hormone combination 0.10 mg/L 6-BA ＋0.05 mg/L NAA performed best in plantlet regeneration and 2.0 mg/L 6-BA ＋0.5 mg/L NAA best in induction of stolon.Various sucrose concentrations did not show significant difference in the impact on sprouted stolons.[Conclusion] Various culture conditions could to some extent impact plantlet regeneration and stolon induction,and our results reveal the optimal hormone combinations for regeneration and stolon induction of S.trifolia.

Effects of “3414” Fertilization Effect Test on the Yield and Economic Benefit of Sagittaria sagittifolia

[Objective] To screen the optimal fertilizer formula, and to lay foundation for the research on special fertilizer for Sagittaria sagittifolia production. [Method] Based on the ＂3414＂ fertilization design, the yield of S. sagittifolia in each treatment was determined, and the effects of N, P and K treatments on the yield and eco- nomic benefit of S. sagittifolia were investigated, obtaining the optimal fertilizer appli- cation ratio. [Result] N, P and K had relatively good effects on the yield of S. sagittifolia. Treatment of N2P2K3 showed the optimal fertilizer application ratio, with the yield of 18 397.80 kg/hm2, yield increasing rate of 104.77%, and net income in- crease of 80 317.35 Yuan/hm2. N fertilizer had the greatest impacts on the yield of S. sagittifolia, followed with K fertilizer; while P fertilizer showed the poorest impacts. [Conclusion] To achieve the highest yield of S. sagittifolia, the fertilizer application was as follows： N of 446.70 kg/hm2, P20 of 568.10 kg/hm2, K2O of 534.90 kg/hm2, when the highest yield was 18 612.75 kg/hm2. Fertilizer application for the optimal economic benefit was N of 420.60 kg/hm2, P2O5 of 70.50 kg/hm2, K2O of 492.15 kg/hm2, when the optimal yield was 18 579.00 kg/hm2.

Cd^(2+)和Cr^(6+)对慈姑(Sagittaria sagittifolia L．)的毒害效应

以水生经济植物慈姑(Sagittaria sagittifolia L．)为实验材料,通过模拟水体Cd2+和Cr6+污染环境,研究了两种单一离子处理对慈姑的毒害影响．结果表明:随着水体Cd2+、Cr6+浓度增大,慈姑叶绿素含量与根细胞质膜透性先升高后降低;Cd2+浓度增大,根和叶的POD活性,叶的SOD活性、丙二醛(MDA)含量及根的超氧阴离子(O2+)产生速率均是先升后降;根和叶的CAT活性、根的SOD活性、MDA含量和叶的O2-产生速率则逐渐升高;而Cr6+处理时,MDA含量、根的 SOD、CAT、POD活性均随浓度增大而升高,O2-产生速率和叶的SOD、CAT、POD活性则升高后降低;Cd2+和Cr6+污染都对慈姑产生毒害,其毒害的效应既有相似性又有差异,同浓度条件下根的受害程度比叶严重．

慈姑(Sagittaria trifolia)根系泌氧特征

借助高精度溶解氧微电极,研究了自然沉积物中慈姑(Sagittaria trifolia)根不同部位的泌氧能力差异以及光照对根系泌氧能力的影响。结果表明,慈姑根系不同部位的泌氧能力存在差异,光照和黑暗条件下根区氧气扩散层厚度由大到小依次为1/2根长(0.98、0.72 mm)、3/4根长(0.68、0.28 mm)、根尖(0.58、0.44 mm)和1/4根长(0.42、0.32 mm);光照条件下不同根长部位根表面溶解氧含量由大到小依次为1/2根长〔64.56%(以%空气饱和度计)〕、3/4根长(52.73%)、根尖(38.55%)和1/4根长(20.55%),这与根部泌氧屏障、通气组织发育程度和根组织呼吸代谢有关。无论有无光照,慈姑根均有泌氧产生,光照条件下根表面溶解氧含量和根区氧气扩散层厚度均高于黑暗条件;在光照和黑暗条件下1/2根长处根表面溶解氧含量均显著高于其他测定点(P<0.05);除1/2根长处以外的其他测定点,在光照条件下的根表面溶解氧含量差异显著(P<0.05),但在黑暗条件下趋于相同(P>0.05)。

Study on Extraction of Polysaccharides and Antioxidant Activity of Sagittaria sagittifolia L.Polysaccharide

[Objective] This experiment was conducted to investigate the optimal ex- traction process and antioxidant activity of polysaccharide in Sagittaria sagittifo/ia L. [Method] The effects of extraction temperature, extraction time, extraction times and material-to-liquid ratio on content of polysaccharides in S. sagittifo/ia were investi- gated. On the basis of single-factor tests, an orthogonal test was carried out to de- termine the optimal process parameters. In addition, the in-vitro antioxidant activity of S. sagittifo/ia polysaccharides was evaluated on the basis of determination of their scavenging activities against DPPH and hydroxyl free radicals and reducing power. [Result] The results showed that the optimized process parameters were as follows： material-to-liquid ratio at 1：40 （g/ml）, extraction temperature at 90 ℃, extrac- tion time of 4 h, and extraction times of 3 times. Under this condition, the content of S. sagittifo/ia polysaccharides was 29.32%. For 1 mg/ml S. sagittifo/ia polysaccha- rides, the scavenging ratios of DPPH and hydroxyl free radicals were 70.62% and 35.82%, respectively, and in the determination of reducing power, the absorbance at 700 nm was 0.453 1. [Conclusion] It could be concluded that S. sagittifolia polysac- charides have strong antioxidant capacity to have free radicals scavenged in vitro.

Extraction and Anti-inflammatory Effects of Colchicine from Sagittaria sagittifolia

[Objective] This study was to study the optimal extraction technology and anti-inflammatory effects of colchicine from Sagittaria sagittifolia. [Method] The ef- fects of ethanol concentration, extraction time, extraction temperature and solid-liquid ratio on the extraction rate of colchicine from S. sagittifolia were investigated. On the basis of single-factor experiments, an L9 （34） orthogonal test was carried out to optimize the extraction process. According to the optimal extraction process, the content of colchicine in S. sagittifolia was determined by high performance liquid chromatography. The anti-inflammatory ability of colchicine was evaluated through an anti-inflammatory test in vitro. [Result] The optimal extraction process of colchicine from S. sagittifolia was as follows： ethanol concentration of 60%, extraction temper- ature of 50℃, extraction time of 30 min, and solid-liquid ratio of 1：25 （g/ml）. The content of colchicine in S. sagittifolia was determined as 40.58 μg/100 mg. Com- pared with the control, the colchicine from S. sagittifolia （9.0 and 4.5 g/kg） inhibited the increase in PGE2, TNF-α and IL-1β contents in pleural fluid （P〈0.05）. High-dose colchicine inhibited the increase in TNF-α, IL-1β and MDA contents in lung tissue （P〈0.01）, and middle-dose colchicine inhibited the increase in IL-1β content in lung tissue （P〈0.01）. [Conclusion] The colchicine in S. sagittifolia has a good anti-inflam- matory effect, which may be achieved through hindering the production of inflam- matory mediators and antioxidation.

High Efficiency of Propagation for Sagittaria sagittifolia Using a Temporary Immersion Bioreactor System

Although several studies have reported on the propagation of the Sagittaria sagittifolia to date, none of these methods have efficiently achieved the mass production of these plants. The present study aimed to investigate the propagation and growth of S. sagittifolia using a temporary immersion bioreactor system （TIBS） compared with conventional semi-solid and liquid culture. The effect of different immersion frequencies and immersion times together with supplementation of various plant growth regulators to the Murashige and Skoog （MS） medium was evaluated on shoot proliferation and plant growth. The results showed that the higher immersion frequency （every 6 h） and shorter immersion time （3 min and 10 rain） in medium containing 4 mg/L BA and 0.1 mg/L NAA produced the highest multiplication rate （23）, which are significantly higher than conventional semi-solid （3.6） and liquid （4.5） method, and the best plant growth parameter. While, the lower immersion frequency and longer immersion time （30 rain every 12 h and 60 min every 24 h） induced vitrification and pollution rate in shoot tips 16.6% and 19%, 42% and 37%, respectively. There is distinct decrease in pollution rate （8.3%） in TIBS （10 min every 6 h） compared with the conventional semi-solid and liquid cultures. Medium containing 4 mg/L BA and 0.5 mg/L NAA using 10 min immersion every 6 h showed satisfaction at the rooting stage, with high shoot proliferation rate （21.6）, 100% rooting and 94% plant survival. Therefore, applying TIBS in S. sagittifolia is an efficient method for scaling up the production of plantlets with high quality seedlings.

慈姑(Sagittaria sagittifolia L．)对环境镉胁迫因子的应答

主要研究了水环境中Cd2+污染对慈姑(Sagittaria sagittifolia L.)根的毒害影响。结果表明:在Cd2+胁迫下,慈姑根出现不同程度的褐变、发黑,生长受到限制;叶和根尖细胞超微结构受损,叶绿体膨大、类囊体排列紊乱、线粒体嵴减少、空泡化、染色质凝集等;根尖细胞在扫描电镜下呈细胞壁增厚、细胞形状扭曲和排列不规则现象。能谱分析结果表明随外界Cd2+浓度增大,单个慈姑根尖中的Cd2+含量升高,其他营养元素的吸收受到不同程度的影响。Cd2+对慈姑的毒害有明显的剂量效应和时间效应。

Changes of Essential Mineral Elements Contents in Response to Cu²⁺Treatment in <i>Sagittaria sagittifolia</i>

Changes of various mineral elements (P, K, Ca, Mg, Fe, Mn, Zn and Na) contents in roots and leaves of S. sagittifolia were studied with treatment of different Cu2+ concentrations (5 μM, 10 μM, 20 μM and 40 μM) after 15 days. The results showed that: 1) Cu accumulated in roots of S. sagittifolia in large quantities, while Cu content in leaves showed no significant change;2) It can be seen from the changes of macroelements that Cu2+ treatments had inhibited the absorption of P, K, Ca, Mg in roots of S. sagittifolia, but the contents of P, K and Mg in leaves were higher than those in the roots in all Cu2+ treatment groups;3) It can be seen from the changes of microelements that Cu2+ treatment promoted the absorption of Fe, inhibited absorption of Mn, Zn and Na in roots of S. sagittifolia, and hindered the transport of various micro-elements from roots to leaves. In all the Cu2+ treatment groups, contents of Fe, Mn, Zn and Na in leaves were lower than those in the roots;4) The critical concentration of Cu2+ to S. sagittifolia was 5 μM. It could be seen from the above results that exogenous added Cu2+ of different concentrations broke the balance of various mineral elements in S. sagittifolia, which would exert a significant impact on numerous metabolic pathways and physiological processes.

野慈姑(Sagittaria trifolia)人工授粉的有效性:授粉工具与花粉保存

人工授粉作为一项关键性技术在生态研究与农业生产领域广泛应用,但是授粉过程中的工具有效性以及花粉保存尚未受到研究者的关注。以植物野慈姑为试验材料,研究了人工授粉方式和花粉保存条件对繁殖的影响。两年的结果表明,相较于直接接触式授粉,借助毛刷工具授粉显著降低了野慈姑的座果概率和种子数。花粉经过半小时野外高温保存后,其授粉的座果概率显著高于对照组,但单果种子数和种子大小保持稳定。综上,在野慈姑的人工授粉中应避免使用毛刷等工具,离体花粉可置于野外环境适当保存。在相关应用中,研究人员应当警惕工具授粉造成的负面影响,注意比较工具与其他授粉方式的等效性,保证实验的科学性。

Production of Sagittaria sagittifolia Beverage and Technological Condition Optimization

[Objectives] To develop a kind of antioxidant health drink which could also regulate blood sugar.[Methods]With Sagittaria sagittifolia,hawthorn and liquorice as raw materials,the orthogonal test was done to determine the optimum preparation ratio of each raw material,optimum flavor modulation ratio and optimum stabilizer type and amount.[Results]Under the conditions of 0. 4% crude polysaccharide powder amount of Sagittaria sagittifolia,10. 0 m L hawthorn extract,2. 5 m L liquorice extract,7. 0% white sugar amount,0. 5% citric acid amount,0. 2% cyclodextrine amount,0. 05 g/L sodium alginate amount,0. 5 g/L xanthan gum amount,2. 0 g/L agar amount and 20 MPa homogenization,the beverage had optimum flavor and stability.[Conclusions]The health drink obtained under these technological conditions had delicate sweet taste and rich nutrition.

慈菇(Sagittaria safittifolia)α-半乳糖苷酶的纯化与性质

以对硝基苯糖苷基为底物，测定了慈菇的１２种糖苷酶，其中α－甘露糖苷酶、α－和β－半乳糖苷酶活力较高；经硫酸铵分级沉淀，ＳｅｐｈａｄｅｘＧ－１５０分子筛层析，ＣｏｎＡＳｅｐｈａｒｏｓｅ４Ｂ亲和层析，ＤＥＡＥ－ＳｅｐｈａｒｏｓｅＣＬ－６Ｂ离子交换层析，从慈菇抽提液纯化了α－半乳糖苷酶。纯化酶的比活提高１０７２倍，活力回收１５．６％，在圆盘聚丙烯酰胺凝胶电泳和ＳＤＳ－ＰＡＧＥ上均显示１条蛋白质带，在α－半乳糖苷酶浓度为１５０ｍＵ／ｍｌ的溶液中测不到其他糖苷酶的活力。慈菇α－半乳糖苷酶的分子量用ＳｅｐｈａｄｅｘＧ－１００凝胶过滤柱测定或在ＳＤＳ－ＰＡＧＥ上测定均为６０ｋＤ，酶反应的最适ｐＨ在５．８附近，最适温度为６０℃。该酶分解对硝基苯基－α－半乳糖苷的Ｋ＿ｍ值为３．７×１０￣（－４）ｍｏｌ／Ｌ，Ｖ＿ｍ值为２．１×１０￣（－４）ｍｏｌ／Ｌ。银离子、汞离子显著抑制酶活力，Ｄ－半乳糖和密二糖均竞争性地抑制该酶水解对硝基苯基α－Ｄ－半乳糖苷的活力，根据Ｄｉｘｏｎ作图求得其Ｋ＿ｉ值分别为０．９２×１０￣（－３）ｍｏｌ／Ｌ和１．９８×１０￣（－３）ｍｏｌ／Ｌ。２－脱氧－Ｄ－半乳糖和Ｌ－岩藻糖为酶活力的非竞争性抑制剂。化学修饰?

Growth inhibition and oxidative damage of Microcystis aeruginosa induced by crude extract of Sagittaria trifolia tubers

Aquatic macrophytes are considered to be promising in controlling harmful cyanobacterial blooms. In this research, an aqueous extract of Sagittaria trifolia tubers was prepared to study its inhibitory effect on Microcystis aeruginosa in the laboratory. Several physiological indices of M. aeruginosa, in response to the environmental stress, were analyzed. Results showed that S. trifolia tuber aqueous extract significantly inhibited the growth of M. aeruginosa in a concentration-dependent way. The highest inhibition rate reached 90% after 6 day treatment. The Chlorophyll-a concentration of M. aeruginosa cells decreased from 343.1 to314.2 μg/L in the treatment group. The activities of superoxide dismutase and peroxidase and the content of reduced glutathione in M. aeruginosa cells initially increased as a response to the oxidative stress posed by S. trifolia tuber aqueous extract, but then decreased as time prolonged. The lipid peroxidation damage of the cyanobacterial cell membranes was reflected by the malondialdehyde level, which was notably higher in the treatment group compared with the controls. It was concluded that the oxidative damage of M. aeruginosa induced by S.trifolia tuber aqueous extract might be one of the mechanisms for the inhibitory effects.

慈姑基因组大小鉴定及核型分析

【目的】慈姑是中国重要的园艺经济作物,其基因组大小的鉴定和核型分析对慈姑基因组学研究及分子遗传学研究必不可少,现阶段慈姑的基因组大小及染色体形态未知,本研究将为慈姑的育种和物种进化研究提供更多细胞学的参考。【方法】采用流式细胞技术、荧光原位杂交技术,参考裂解液配方、探针配置,对慈姑品种‘紫金星’(ZJX)的根尖基因组大小进行鉴定,并对其染色体形态进行分析观察。【结果】(1)所测慈姑为二倍体植物,‘紫金星’慈姑基因组为16 Gb左右。(2)用DAPI荧光染色获得其染色体数目稳定,且与端粒荧光原位杂交的结果完全吻合,均为22条;染色体类型有中部着丝粒、近中部着丝粒以及近端部着丝粒,近端部着丝粒最多,且未发现随体;核型公式为:2n=2x=22=6m+4sm+12st,属于Stebbins类型中的3B型,核型不对称系数为99.13。【结论】慈姑基因组大小中等,核型极不对称,进化程度较高。

水田慈姑植保无人机施药装置设计与试验

针对水田慈姑蚜虫虫害防治的低量定向施药需求,在对水田环境、慈姑植株特性以及慈姑蚜虫防治等调研的基础上,设计了水田慈姑植保无人机施药装置。利用有限元软件进行四旋翼植保无人机旋翼下风场和施药场数值模拟,并对平台进行不同工况的喷雾试验研究。结果表明:悬停高度提高,旋翼下流场强度分布层次丰富,更容易产生雾滴偏移;飞行速度降低,来流造成的雾滴飘移减小;喷头流量为20mL/min、压力增加达到0.07MPa时,喷头雾化达到最佳工况。无人机高度降低,喷洒雾滴附着率增加,无人机速度降低,喷洒雾滴附着率增加。因此,低空低速条件下雾滴叶片附着率更高、施药效果更佳,可实现可靠高效的慈姑病虫害防治。

培养基配方对慈姑花粉萌发与花粉贮藏寿命的影响

比较筛选了慈姑(Sagittaria trifolia)花粉萌发培养基配方,观测了不同慈姑品种花粉在室温(25℃)和低温(4℃)贮藏条件下活力变化动态。结果表明,慈姑花粉萌发最适培养基配方为10%蔗糖+50μg/mL硼酸;慈姑花粉室温(25℃)条件下贮藏24 h、低温(4℃)条件下贮藏30 h时其活力较低,6 h内花粉具有较高活力;不同慈姑品种花粉活力存在一定差异。

典型的草甸和冠层型沉水植物对内源污染物削减效果研究

【目的】探究不同生长模式的沉水植物对内源污染物的削减效果。【方法】选取典型的草甸型和冠层型沉水植物矮慈姑和轮叶黑藻,利用采自重污染水体的底泥和两种沉水植物分别构建实验模拟系统,研究分析矮慈姑和轮叶黑藻在污染底泥中的生长扩增、各系统底泥和上覆水中主要污染物的浓度变化及表层底泥微生物群落结构的特点。【结果】两种沉水植物均能耐受污染底泥并生长扩增,矮慈姑茎、叶和根系的生物量均扩增10倍,但主要集中在水底泥界面上下10 cm范围;轮叶黑藻茎、叶的生物量在整个上覆水空间扩增也达到10倍,但根系生物量不变。矮慈姑系统表层底泥(0~10 cm)的酸可挥发性硫化物(AVS)、亚铁和氨氮,去除率分别达到80.57%、67.43%和72.48%,轮叶黑藻系统亚铁和氨氮去除率只有24.75%和61.41%,AVS上升13.6%。矮慈姑和轮叶黑藻系统上覆水中叶绿素a的浓度分别为9.61、9.39μg/L。16S rRNA高通量测序结果显示,两类系统表层底泥微生物群落中属的组成差异显著,矮慈姑系统优势属为硫曲菌属(Sulfurifustis)和硝化螺旋菌属(Nitrospira),而轮叶黑藻系统中Cyanobium_PCC-6307、螺旋体菌属(Spirochaeta_2)、假平胞菌属(Sphingomonas)和地杆菌属(Geothermobacter)的相对丰度更高。【结论】矮慈姑对表层底泥中还原性污染物AVS、亚铁和氨氮具有更好的去除效果,而轮叶黑藻则对于上覆水藻类的生长具有更好的控制效果。矮慈姑发达的根系促进了硫和氨氮代谢微生物类群的发育。