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岩生红豆(Ormosia saxatilis)隶属豆科(Leguminosae)红豆属(Ormosia)植物,常绿乔木,我国特有种,贵州省级保护树种 [1-3]。树形优美,为珍贵的庭院绿化观赏树种;其种子具有清热解毒、消肿除湿功效,为重要药材[4];树干通直,材质优良,纹理美观,为珍贵的红木类用材树种。据调查,现有资源不超过500株,多为伐桩萌蘖(或根蘖)幼苗幼树,成熟个体不足100株,天然个体数量极少,已达极危等级,其资源保护与拯救迫在眉睫[5-6]。目前,解决植物资源濒危问题主要是以建立自然保护区、森林公园等自然保护地的办法进行物种保护,这在一定程度上保存了濒危植物的现有资源数量,但要从根本上解决植物资源濒危稀少的问题关键在于扩大资源数量。提高濒危植物种群繁衍能力和数量,最有效的办法是开展植物种苗繁育研究。调查发现,野生的岩生红豆很少有实生树木,即使是在已结实的大树下也很少发现有实生幼苗,说明岩生红豆种子在自然状态下萌发困难,仅仅通过保护的办法很难实现资源数量的增加,最有效的办法是进行种子繁育研究。目前,针对岩生红豆的研究主要集中在种群与群落、生态位等方面[7-8],而在岩生红豆种苗繁育方面未见报道。植物种子萌发是种苗繁育的基础,开展种子萌发特性研究必将为种苗繁育奠定理论基础,为植物资源数量提供基础保障。本文以岩生红豆种子为试验材料,研究了岩生红豆种子萌发特性及种子萌发限制因子,以期为进一步提高岩生红豆种苗繁育提供理论依据,进而解决岩生红豆的濒危状况。
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岩生红豆种子物理性状如表1所示,岩生红豆种子平均长径为0.96 cm,长径范围为0.59~1.12 cm,变异系数为8.17%;种子平均短径为0.82 cm,短径范围为0.51~0.93 cm,变异系数为6.49%;种子千粒重为419.4 g,种子重量范围0.182~0.424 g,平均单粒重为0.407 g,单粒重变异系数为12.42%;含水率为12.68%。从岩生红豆种子物理性状测定结果看,该种子属于中粒种子,种子大小变化较大。千粒重与种子长短经大小呈正比,种子长短经越大,种子越重。
长径/cm Long diameter 短径/cm Short diameter 重量/g Weight 含水量/%
Water content变动范围
Variation range平均值
Mean变异系数/%
Variable coefficient变动范围
Variation range平均值
Mean变异系数/%
Variable coefficient千粒重
1000-seeds weight单粒重
变动范围
Variation range平均单粒重
Average single grain weight单粒重变
异系数/%
Variable coefficient0.59~1.12 0.96 8.17 0.51~0.93 0.82 6.49 419.4 0.182~0.424 0.407 12.42 12.68 Table 1. Determination of physical properties of Ormosia saxatilis seeds
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岩生红豆种子吸水率及累计吸水率如图1所示,岩生红豆种子吸水率处理组(B)与对照组(A)差异较大,未进行处理(A)的岩生红豆种子吸水率极低,用小刀划伤种子种皮后种子吸水率得到了很大的提高。说明岩生红豆种子种皮非常致密,透水性较差,划伤种皮后有助于岩生红豆种子吸水萌发。从处理组(B)来看,岩生红豆种子吸水率随时间的增加而增大,但在16 h内吸水率均较低,累计吸水率仅为15.35%,16 h后吸水率迅速提高,在36 h时吸水率达到最大值,吸水率为33.2%,在96 h时吸水率达到恒定,累计吸水率达63.63%,比为做处理的吸水率高60.56%。
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由表2可知,在不同预处理条件下,岩生红豆种子的发芽开始时间、发芽结束时间和发芽高峰期均产生了明显的变化。与未去皮处理(A1)相比,去皮处理(A3)的岩生红豆种子发芽开始时间、发芽结束时间和发芽高峰期均有所提前,发芽开始时间提前了4.3 d,发芽结束时间提前了13.7 d,发芽高峰期提前了5.5 d;三者开始发芽、发芽结束和发芽高峰期所用时间长短顺序均为A1>A2>A3。不同预处理的岩生红豆种子发芽率和发芽势差异显著(p < 0.01),
预处理
Pretratment温度处理
Temperature treatment发芽开始时间/d
Start time发芽结束时间/d
End time发芽高峰期/d
Fastigium发芽率/﹪
Germination percentage发芽势/﹪
Germination energyA1 B1 17 45 29 19.0 ± 1.3 f 17.0 ± 0.9 g B2 12 42 25 28.0 ± 1.1 d 22.0 ± 1.2 de B3 15 43 26 21.0 ± 1.2 e 19.0 ± 1.1 f B4 19 48 31 11.0 ± 1.0 g 18.0 ± 1.0 fg 平均值 15.3 44.5 27.8 19.8 ± 1.1 ef 19.0 ± 1.1 f A2 B1 13 40 27 32.0 ± 1.4 d 31.0 ± 1.7 d B2 9 37 22 41.0 ± 1.6 bc 49.0 ± 1.9 b B3 12 39 23 37.0 ± 1.3 c 41.0 ± 1.4 c B4 15 43 27 33.0 ± 1.3 d 31.0 ± 1.3 d 平均值 12.3 39.8 24.8 35.8 ± 1.4 cd 38.8 ± 1.4 d A3 B1 12 33 25 39.0 ± 1.9 c 33.0 ± 1.1 d B2 8 24 20 61.0 ±2.1 a 55.0 ±1.9 a B3 11 31 21 45.0 ± 1.7 b 49.0 ± 1.9 b B4 13 35 23 37.0 ± 2.1 c 27.0 ± 1.0 de 平均值 11 30.8 22.3 45.5 ± 1.4 b 41.0 ± 1.2 c 注:不同小写字母分别表示各处理分析指标间存在极显著差异。下同。
Note: Different lowercase letters indicate significant differences among different treatments. The same below.Table 2. Analysis of seed germination of Ormosia saxatilis under different pretreatment and temperature combinations
发芽率和发芽势均以A3最大,分别为45.5%和41.0%,其次是A2,A1处理的种子发芽率和发芽势均最小,比A1处理的种子发芽率高25.7%。为25.7%。在变温30℃/25℃(B1)下,A3发芽率与A1发芽率之差为20%,发芽势之差为16%;在变温25℃/20℃(B2)条件下,A3发芽率与A1发芽率之差为33%,发芽势之差为33%;在恒温25℃(B3)下,A3发芽率与A1发芽率之差为24%,发芽势之差为20%;在恒温20℃(B4)下,A3发芽率与A1发芽率之差为26%,发芽势之差为9%。说明岩生红豆种子种皮致密,透水透气性差,影响其萌发对水分和氧气的吸收,导致岩生红豆种子发芽受阻,在去除种皮或部分去皮的情况下,岩生红豆种子吸收水分和氧气的限制因素得到了缓解,进而促进种子发芽。
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由表2可知,温度也是影响岩生红豆种子发芽开始时间、发芽结束时间和发芽高峰期的一个关键因子,在变温25℃/20℃条件下,岩生红豆种子发芽开始时间、发芽结束时间和发芽高峰期均为最短,其次是恒温25℃条件下的种子,变温30℃/25℃和恒温20℃条件下时间最长。从发芽率和发芽势来看,在同一预处理条件下不同温度处理的岩生红豆发芽率和发芽势差异显著(p<0.01)。在变温25℃/20℃(B2)条件下岩生红豆种子发芽率和发芽势均为最高,分别为61.0%和55.0%;其次为恒温25℃(B3)处理的种子,分别为45.0%和49%;变温30℃/25℃和恒温20℃处理的种子发芽率和发芽势均为最低。在A3处理下B2与B4发芽率、发芽势之差分别为24%、28%;在A2处理下B2与B4发芽率、发芽势之差分别为8%、18%;在A1处理下B2与B4发芽率、发芽势之差分别为17%、4%。表明,岩生红豆种子最佳发芽温度为25℃/20℃(B2)。
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由表2可知,在种皮和温度处理的2个组合中,A3B2组合条件下岩生红豆种子发芽率和发芽势均为最高,分别为61.0%和55.0%;A3B3次之,分别为45.0%和49.0%;组合处理表现最差的是A1B4,分别为11.0%和18.0%;说明岩生红豆种子发芽以全部去除种皮,变温25℃/20℃发芽效果最好。
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由表3可知,与对照组相比,种皮浸提液和种胚浸提液均对白菜种子的萌发具有抑制作用。对于同种浸提液而言,不同浓度处理对白菜种子发芽率和萌发抑制率均存在显著差异(p<0.01),且随着浓度的增加种子发芽率逐渐降低,萌发抑制率逐渐增大。种皮浸提液在0.01 g·mL–1、0.05 g·mL–1和0.1 g·mL–1浓度时的白菜种子发芽率分别比对照组降低20.0%、42.0%和64.0%,萌发抑制率增加25.6%、53.9%和84.6%;种胚浸提液浓度为0.01 g·mL–1、0.05 g·mL–1和0.1 g·mL–1时的白菜种子发芽率分别比对照组降低8.0%、16.0%和38.0%,萌发抑制率增加10.3%、20.5%和48.7%;此外,在相同浸提液浓度下,种皮浸提液对白菜种子萌发的抑制作用明显高于种胚,浸提液浓度为0.01 g·mL–1时,种皮浸提液处理的萌发抑制率比种胚高15.3%; 浸提液浓度为0.05 g·mL–1时,种皮浸提液处理的萌发抑制率比种胚高33.4%, 浸提液浓度为0.1 g·mL–1时,种皮浸提液处理的萌发抑制率比种胚高35.9%,说明岩生红豆种皮浸提液中抑制种子萌发的物质明显高于种胚。
抑制处理
Inhibition treatment白菜种子发芽数
Germination number of
Brassica campestris白菜种子发芽率/%
Germination rate of
Brassica campestris萌发抑制率/%
Germination inhibition rateCK(蒸馏水) 39 78.0 ± 2.1 a 0.0 ± 0.0 f 种皮浸提液
Seed coat extract0.01 g·mL–1 29 58.0 ± 1.2 d 25.6 ± 2.7 d 0.05 g·mL–1 18 36.0 ± 1.1 e 53.9 ± 3.0 c 0.1 g·mL–1 6 12.0 ± 1.0 f 84.6 ± 3.1 a 种胚浸提液
Seed embryo extract0.01 g·mL–1 35 70.0 ± 2.6 b 10.3 ± 1.0 e 0.05 g·mL–1 31 62.0 ± 2.2 c 20.5 ± 1.0 d 0.1 g·mL–1 20 40.0 ± 1.2 e 48.7 ± 2.0 b Table 3. Analysis on seed germination of Brassica campestris under different extracts treatment conditions
Study on Seed Germination Characteristics of Endangered Tree Species Ormosia saxatilis in Guizhou Province
doi: 10.12172/202010100001
- Received Date: 2020-10-10
- Available Online: 2022-01-13
- Publish Date: 2022-03-02
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Key words:
- Ormosia saxatilis /
- Seed germination /
- Bioassay /
- Germination inhibitory substance /
- Germination rate
Abstract: In order to explore the germination characteristics of Ormosia saxatilis seeds and limiting factors affecting seed germination, the physical properties and water absorption of Ormosia saxatilis seeds were measured, and two combinations of seed coat pretreatment and germination temperature treatment were carried out, and the methanol extracts of seed coat and embryo were measured by bioassay. The results showed that the seeds of Ormosia saxatilis were dormant, and the seed coat was hard and compact, less permeable breathability. Scratching the Ormosia saxatilis seed coat with a knife could effectively improve the permeability of the seed coat, and the cumulative water absorption rate in 96 h reached 63.63%, which was 60.56% higher than that of untreated seeds. The germination rate of peeled Ormosia saxatilis seeds was the highest, reaching 45.5%, which was 25.7% higher than that of non-peeled seeds. The germination of Ormosia saxatilis was limited by seed coat, and the combination of seed coat removal and temperature change at 25℃/20℃ had the best germination effect, with the gemination rate as high as 61.0%. The seed coat extract and embryo extract of Ormosia saxatilis could inhibit the gemination of Brassicca campestris seeds. With the increases of extract solution concentration, the germination inhibition rate gradually increased and the seed germination rate gradually decreased. The inhibitory effect of seed coat extract was significantly higher than that of embryo. Compared with the control, the germination rate of Brassicca campestris seeds treated with 0.01g·mL−1, 0.05g·mL−1 and 0.1g·mL−1 seed coat methanol extract decreased by 20.0%, 42.0% and 64.0% respectively, and the germination inhibition rate increased by 25.6%, 53.9% and 84.6% respectively. It was preliminarily considered that the reasons for seed dormancy of Ormosia saxatilis was poor seed coat permeability, and the inhibitory substances contained in seed coat and embryo.