秤锤树种子中发芽抑制物初步研究

对秤锤树(Sinojackia xylocarpa Hu)种子的种皮和种仁(含胚和胚乳)进行水浸提和甲醇浸提,分别测定了浸提液对白菜种子萌发的抑制效应,探讨了秤锤树种子中萌发抑制物质存在类型和存在部位.结果表明:秤锤树种子种皮和种仁的水浸提液对白菜种子发芽率和幼苗的高生长、根生长均无显著抑制作用(P>0.05),而其甲醇浸提液对白菜种子发芽率和幼苗的高生长、根生长有显著或极显著抑制作用(P<0.05或P<0.01),且随浸提液质量分数的增大,抑制作用逐渐增强;且种仁甲醇浸提液对白菜种子发芽和生长的抑制效应极显著(P<0.01)大于种皮甲醇浸提液.表明秤锤树种子的种皮和种仁均含有抑制种子萌发和幼苗生长的酯溶性物质,且该类物质主要贮藏在种仁中.     

南方红豆杉叶浸提液对小麦种子萌发与幼苗生长的影响

采用滤纸培养皿法研究了南方红豆杉叶浸提液对小麦种子萌发与幼苗生长的影响。研究结果发现,红豆杉叶浸提液对小麦种子的萌发和幼苗生长存在不同程度的抑制作用。低浓度的南方红豆杉浸提液促进小麦种子的萌发,高浓度浸提液抑制小麦种子的萌发。当浸提液浓度为6g/mL时,小麦种子的萌发率达到最高。南方红豆杉叶浸提液对小麦幼苗根系生长产生显著抑制作用。随着浸提液浓度的升高,小麦须根的长度逐渐下降,但不定根的数目逐渐增加。当浸提液的浓度为10g/mL时,根长抑制率达到42.48%。方差分析结果表明,南方红豆杉叶浸提液对小麦的根生长产生显著的抑制作用。对小麦幼苗的茎生长、根的生物量和茎的生物量均表现为低浓度的浸提液促进茎的生长和生物量的增加,高浓度浸提液则抑制茎的生长和生物量增加。研究结果表明,南方红豆杉浸提液表现低浓度时促进种子的萌发、须根数目的增加、茎的生物及生物量的增加,高浓度时则产生一定的抑制作用,而对根长的生长表现为显著的抑制作用。     

林下枯落物浸提液对香果树种子萌发及幼苗生长影响的化感效应

研究了香果树的落叶、树枝、果皮及竹叶等4种林下枯落物浸提液对香果树种子萌发和幼苗生长的化感效应。结果表明:香果树落叶、树枝及竹叶浸提液对香果树种子萌发具有不同程度抑制作用,并随浓度升高抑制作用增强。对香果树幼苗生长的化感效应,香果树落叶和果皮浸提液具有显著抑制作用,随浓度升高抑制作用增强;香果树树枝浸提液总体趋势具有“低促高抑”的双浓度效应;竹叶浸提液对香果树幼苗不同部位化感效应不同,具有“促茎抑叶”的化感效应。     

华山姜浸提液对杉木种子萌发及幼苗生长的影响

为探讨杉木林下种植华山姜潜在的化感作用，采用水浸提法，用华山姜不同器官、不同浓度浸提液进行杉木种子发芽试验，比较不同处理对杉木种子萌发和幼苗生长指标的影响。结果表明：华山姜果实浸提液对杉木种子萌发和幼苗生长指标均表现出低促高抑的规律；干叶片浸提液对杉木种子萌发和幼苗生长指标均表现出抑制作用；新鲜叶片浸提液对杉木种子萌发和幼苗生长指标均无显著影响；根浸提液对杉木种子发芽率和发芽指数及幼苗叶片生长有促进作用，对幼苗茎生长有抑制作用，对幼苗根生长影响不显著。表明华山姜不同器官浸提液中具有化感活性物质，杉木林下种植华山姜时，需及时清理枯落叶、防止果实过度脱落并及时采摘。     

紫茎泽兰植株不同部位及浓度的水提液对蓝桉种子萌发和幼苗生长的化感效应

为探讨紫茎泽兰不同部位水提液对蓝桉的化感作用,用紫茎泽兰植株的鲜叶、花、枯叶、茎和根的不同浓度水提液对蓝桉种子进行处理.结果表明,花和鲜叶水提液对蓝桉种子的萌发和幼苗生长的抑制作用远大于枯叶、茎和根的水提液.浓度为0.067 g/mL时,对花和鲜叶的水提液来说,几乎是蓝桉种子萌发和幼苗生长的致死浓度,此浓度的枯叶、茎和根水提液对蓝桉种子萌发和幼苗生长有很强的抑制作用,导致发芽量明显下降及幼苗在形态上发生明显变形;浓度为0.020 g/mL时,花和鲜叶水提液对蓝桉种子萌发及幼苗生长仍有很强的抑制作用,表现在发芽量明显下降及幼苗明显变形,而枯叶、茎和根水提液对蓝桉种子萌发和幼苗生长的抑制作用明显下降,甚至有促进作用,幼苗变形已大为减轻.浓度为0.005 g/mL时,不同部位的水提液对蓝桉种子萌发及幼苗生长的抑制作用进一步下降,而促进作用增强,幼苗已能正常生长.     

北美鹅掌楸种子外种皮发芽抑制物研究

北美鹅掌楸(Liriodendron tulipifera L.)种子具有深休眠习性。以其种皮浸提液作为白菜种子的萌发液，结果表明浸提液对白菜种子的萌发没有影响，但对幼苗和根系生长有一定的抑制作用，表明北美鹅掌楸种子的休眠不是由外种皮引起的。     

水杨酸浸种处理对干旱胁迫下云南蓝果树种子萌发和早期幼苗生长的影响

利用不同浓度的水杨酸(0g/L、0.25g/L、0.5g/L、0.75g/L、1g/L)对云南蓝果树种子进行浸种处理和不同浓度的PEG-6000溶液(0、5%、10%、15%)模拟不同强度的干旱胁迫,研究水杨酸浸种处理对干旱胁迫下云南蓝果树种子萌发和早期幼苗生长的影响。结果表明,未经SA浸种处理时,轻度干旱胁迫就显著抑制了云南蓝果树种子的萌发,且随着PEG-6000胁迫浓度的增加,云南蓝果树种子的萌发率、发芽势、发芽指数、活力指数、幼苗根长、根冠比以及根干重、根鲜重、子叶鲜重和子叶干重都显著下降。SA溶液浸种后(SA溶液浓度范围为0.25~1.0g/L),在不同程度干旱胁迫条件下(PEG-6000浓度为5%~15%),云南蓝果树种子萌发率、发芽势、发芽指数、活力指数、根长、根干重、根鲜重、子叶鲜重和子叶干重都显著高于对照,并随着SA浓度的增加而显著增加,在SA浓度为0.75g/L时,增加幅度最显著。因此,云南蓝果树对干旱环境具有非常差的耐受性,但是SA的浸种处理可以缓解干旱胁迫对云南蓝果树种子萌发和早期幼苗生长的影响。建议育苗前对云南蓝果树种子进行SA预处理,最适浓度为0.75g/L。本研究为水杨酸在云南蓝果树保育中的应用提供了科学依据。     

银杏外种皮提取物对植物种子萌发及幼苗生长的影响

以萝卜和黄瓜种子为试验材料,研究了不同质量浓度的银杏外种皮提取物溶液对2种植物种子萌发及幼苗生长的影响。结果表明:提取物溶液在一定质量浓度范围内对萝卜、黄瓜种子萌发及幼苗生长具有显著抑制作用。当质量浓度20~100 g/L时对萝卜种子萌发具有显著的抑制作用,0.1~100 g/L时对萝卜根、茎生长显著抑制;当质量浓度0.02~25 g/L时对黄瓜种子萌发、根生长具有显著的抑制作用。     

杨树对紫花苜蓿种子萌发的化感效应

该文研究了中辽1号杨叶片、根系、根际土浸提液对紫花苜蓿种子萌发的化感效应。结果表明:杨树叶片、根系浸提液对紫花苜蓿种子萌发及幼苗生长的化感效应为负效应,起抑制作用,且质量浓度越大抑制效果越明显,相同质量浓度的叶片浸提液抑制作用大于根系浸提液的抑制作用;高质量浓度杨树根际土浸提液对紫花苜蓿种子萌发及幼苗生长的化感效应为负效应,起到了抑制作用,但低质量浓度杨树根际土浸提液的化感效应为正效应,起到了促进作用。初步认为,杨树林下适宜种植紫花苜蓿。     

薄壳山核桃叶不同溶剂浸提物对高丹草的化感效应比较

为探究薄壳山核桃叶中的化感物质对植物生长的影响,采用室内种子发芽的方法,通过生物测定研究了石油醚相、氯仿相、乙酸乙酯相、甲醇相浸提液对高丹草种子萌发和幼苗生长的影响。结果表明,不同溶剂提取液对高丹草种子萌发和生长的影响不同。甲醇相对种子发芽率、发芽势、发芽指数、茎长起极显著的抑制作用,抑制指数分别达到0.13、0.13、0.23、0.61;对幼苗鲜重和根长起显著性抑制作用,抑制指数分别达到0.13、0.31。乙酸乙酯相对种子发芽指数也起到极显著抑制作用,抑制指数为0.13。而石油醚相、氯仿相对种子发芽势、平均发芽速度、根长、茎长等指标都有不同程度的影响,但差异都不显著。各相态对种子发芽率和可溶性蛋白质合成起抑制作用。其中甲醇相对发芽率抑制作用最大,抑制指数达到0.13;乙酸乙酯相对幼苗体内可溶性蛋白质合成抑制作用最大,抑制指数达到0.84。不同溶剂浸提薄壳山核桃叶获得的化感物质对高丹草种子萌发和幼苗生长影响不同,可能与其体内不同种类的蛋白质合成与表达变化有关。     

无瓣海桑对乡土红树植物的化感作用

以外来种无瓣海桑为供体,通过室内栽培实验探讨了无瓣海桑各器官水浸液的不同浓度(即0 1、0 2、0 3、0 4、0 5g·mL-1)对我国4个乡土红树植物的化感作用。结果表明:无瓣海桑对各乡土红树植物均存在化感作用,对胚轴萌发的影响大于对幼苗生长的影响;除最低浓度外,不同浓度的各器官水浸液均能明显抑制各乡土红树植物的萌发,且随着浓度增大抑制作用增强;所有水浸液均表现出高浓度下抑制幼苗生长,随着浓度的降低抑制作用减弱,甚至转为促进的规律;各器官的水浸液对各乡土红树植物的萌发和幼苗生长的抑制作用为:果>根>凋落叶;高浓度时,无瓣海桑的各器官水浸液对不同受体红树植物的幼苗生长抑制强度不同。     

Germination and early seedling growth of <Emphasis Type="Italic">Pinus densata</Emphasis> Mast. provenances

We studied seed germination and early seedling growth of Pinus densata to explore the range of variability within the species and to inform afforestation practices. Phenotypes were evaluated at a forest tree nursery under conditions that support Pinus yunnanensis, one of the presumed parental species of P. densata. Seeds were collected from 20 open-pollinated trees within each of eight autochthonous populations representing the natural distribution of P. densata in China to assess variation in germination traits and early seedling growth, and to examine the relationships among these traits. Results showed that seeds from all populations germinated and seedlings established successfully. There were significant differences among populations in 13 of 14 traits evaluated. Seed germination and early seedling growth were strongly related to seed size and seed weight. Bigger seeds germinated earlier and faster than small seeds, and seedling size was positively correlated with seed size. Some germination traits were strongly and significantly correlated with climatic variables associated with the provenance of the studied populations. Based on these observations, we conclude there were large, significant, and biologically important differences among P. densata populations in seed germination and seedling growth traits. The observed variability probably reflects a high degree of adaptive differentiation among populations that is likely to be relevant for future afforestation.     

外来树种火炬树化感作用的研究

以盐肤木和黄栌为参照树种,用火炬树树叶水浸提液、林下土壤水浸提液浸种24 h,研究了浸提液对侧柏、油松、香椿、臭椿、小麦、小白菜种子萌发及幼苗生长的影响,研究了火炬树的化感作用。结果表明:火炬树完整鲜叶水浸提液处理小白菜种子,其发芽率和发芽势分别为88.0%、82.5%,与对照发芽率(94.0%)和发芽势(91.5%)无显著差异,而破碎鲜叶水浸液则极显著影响小白菜的发芽率和发芽势,分别降低为24.8%和5.0%;火炬树完整鲜叶和破碎鲜叶水浸液都能促进小白菜苗高生长,但都抑制小白菜胚根的伸长。与鲜叶相比,火炬树干叶水浸提液的化感作用明显降低。火炬树破碎鲜叶水浸提液极显著影响小麦发芽率,分别比对照的发芽率和发芽势降低11.0%和83.5%,干叶水浸提液则不影响小麦的发芽率,为95.0%,但发芽势比对照降低23.0%。与盐肤木和黄栌相比,火炬树破碎鲜叶水浸提液对小麦幼茎及胚根生长的抑制作用最强。火炬树破碎鲜叶水浸提液对4个乡土树种的种子萌发产生了不同程度的抑制作用,对香椿及臭椿发芽率的抑制作用极显著。火炬树破碎鲜叶水浸提液对4个树种的苗高以及油松苗胚根的伸长没有显著影响,但却极显著地抑制了侧柏、香椿及臭椿胚根的伸长。火炬树林下表层土壤水浸提液对小麦幼苗的生长没有抑制作用,能明极显著促进香椿的生长;处理55 d时,香椿苗平均高为8.63 cm,极其显著高于对照(5.14 cm)。     

Variation in seed and seedling traits and their relations to geo-climatic factors among populations in Yunnan Pine (<Emphasis Type="Italic">Pinus yunnanensis</Emphasis>)

Differences in seed germination and seedling growth among populations of Pinus yunnanensis Franch. were quantified to provide information for use in the regeneration, reforestation, and improvement of this species. Seed germination and seedling growth traits at the nursery stage were investigated at the population level. We evaluated relationships between pairs of measured traits as well as the association between measured traits and geo-climatic variables including longitude, latitude, elevation, temperature and precipitation. Seedling growth showed significant differences although a low magnitude of variation was found in the seed germination traits among the populations. Some populations with strong and stable growth (e.g., the Baoshan population) may be selected as superior seed sources for regeneration and reforestation. Germination percentage was negatively correlated with elevation, and positively with precipitation. In addition, germination index, vigor index and seedling height were positively correlated with precipitation. Seed germination index, cotyledon number and length, and seedling diameter were significantly and positively correlated with seed weight. Strong correlations between pairs of traits will be helpful in early evaluations for the selection of certain prominent traits.     

卷叶黄精根不同极性化感物质的化感作用

化感作用是植物通过淋溶、挥发、残茬降解和根系分泌向环境中释放化学物质,从而对自身或周围其他植物的生长产生影响的现象(孔垂华等,2001;董卓杭等,2001;翟明普等,1993;林文雄等,2001;马茂华等,1999;彭少麟等,2001).化感作用普遍存在于自然界,对其深入研究将有利于复合系统中植物配置、耕作制度和栽培措施的科学化,在植物间加强促进作用,降低抑制作用,促进生物多样性和农业可持续发展.     

高山栲水提液对云南松种子发芽的化感效应

为了解混交树种高山栲对云南松的化感作用,用高山栲各器官水提液对云南松种子的发芽进行处理。结果表明,高山栲鲜叶、枝干、树皮、树根,枯落叶水提液对云南松种子的发芽和芽的生长均有一定的影响。所有样品的水提液均表现出在高浓度下对云南松种子发芽和芽的生长有明显抑制作用,随着水提液浓度减小,抑制作用减弱、消失甚至转变为促进作用的规律;其中枝干和鲜叶水提液对云南松种子发芽和芽的生长作用强度最大;发芽效果不同指标对高山栲各器官水提液作用的敏感性次序是:鲜重>根长>发芽率>胚轴长。说明在营造云南松和高山栲混交林时,高山栲比例适当减小将有利于云南松的天然更新和生长。     

紫茎泽兰水浸提液对慈竹种子萌发及幼苗生长的影响

以浓度为0(对照)、0.25%、1.00%、2.00%、3.00%的紫茎泽兰水浸提液处理慈竹种子,研究其水浸提液对慈竹种子萌发和幼苗生长的化感作用。研究结果表明,紫茎泽兰水浸提液对慈竹种子的萌发和生长都起到显著影响。在低浓度处理下,浸提液具有低剂量刺激效应,可提高慈竹种子的发芽率、发芽势;随着浓度的升高,慈竹种子发芽率、发芽势显著降低,同时,幼苗的鲜重、根冠比先增加后降低;丙二醛含量、SOD酶活性与浸提液的浓度呈正相关;POD酶活性则先上升,后下降,但均高于对照组。这说明较高浓度的紫茎泽兰水浸提液可显著抑制慈竹种子萌发和幼苗的生长,其入侵林地后对竹林的生产和经营存在潜在威胁。     

飞机草水提液对任豆种子萌发和幼苗生长的影响

以任豆为受体植物,研究了飞机草根、茎和叶的水提液对任豆种子萌发和幼苗生长的化感效应。结果表明,不同浓度水提液对任豆的化感作用强度不同,在100%高浓度下才能明显延缓任豆种子发芽速率和显著抑制幼苗根的生长;在不同部位水提液中,叶水提液的化感作用最强,且表现出低促高抑的现象;而各部位、各浓度的飞机草水提液对任豆的发芽率、苗高和干重等重要指标均无显著抑制作用,表明任豆对飞机草的化感作用具有较强抵抗力。     

Allelopathic effects of invasive Eucalyptus camaldulensis on germination and early growth of four native species in the Western Cape,South Africa

Eucalyptus camaldulensis Dehnh. (red river gum; Myrtaceae) is an invasive tree in riparian habitats of the Western Cape, South Africa, where it replaces indigenous vegetation and affects ecosystem functioning. These invasions lead to changes in river geomorphology and reduction in stream flow. The mechanisms that drive these effects are poorly understood. The potential for allelopathic effects of aqueous extracts of E. camaldulensis tissues and of soil and litter collected beneath E. camaldulensis trees on the germination and seedling growth of four selected native plant species was investigated in a greenhouse experiment. Soils collected beneath E. camaldulensis trees were used in three treatments: untreated soils, sterilised soils and sterilised soils overlaid with a eucalypt litter layer. In addition, soils collected from underneath native species were used in two treatments: untreated soils and soils overlaid with a eucalypt litter layer. All soil treatments were watered with three E. camaldulensis leaf, bark and root aqueous treatments. Compounds present in the aqueous extracts and fresh samples were identified using gas chromatography. Soil and aqueous treatments showed varying effects on germination and seedling growth of the four native species. Germination and seedling growth of Olea europaea subsp. africana and Dimorphotheca pluvialis were significantly reduced by E. camaldulensis root and bark aqueous extracts as well as by the soils treatments. The addition of eucalypt litter to native and sterilised soils reduced shoot and root growth of all four native species. Compounds such as -phellandrene, eucalyptol, p-menth-1-en-8-ol and -pinene, which have the potential to inhibit germination and plant growth, were identified in E. camaldulensis aqueous extracts and fresh samples. Although the methods applied in this study had limitations (e.g. lack of control treatment to litter addition), the results provide an additional motivation to prioritise removal of invasive E. camaldulensis stands from riparian ecosystems. Restoration initiatives should target native species that are not negatively affected by allelopathy.