2024年7月21日 星期日
赤霉素和干旱胁迫单一处理对珍稀濒危植物小溪洞杜鹃种子萌发的影响
Effects of single treatments of gibberellin and drought stress on seed germination of rare and endangered plant Rhododendron xiaoxidongense
2022年 第31卷 第4期 页码[57-64]    下载全文[3.3MB]  
摘要

为了确定赤霉素和干旱胁迫对小溪洞杜鹃(Rhododendron xiaoxidongense W. K. Hu)种子萌发的影响,对江西井冈山野生小溪洞杜鹃的种实形态特征进行了观测,对质量浓度0~500 mg·L-1赤霉素3(GA3)和质量体积分数0%~20%聚乙二醇-6000(PEG-6000)处理下小溪洞杜鹃的种子萌发指标进行了比较,并对GA3和PEG-6000浓度与种子萌发指标进行了Pearson相关性分析。结果表明:小溪洞杜鹃的果实为蒴果,密被长腺毛;种子长和宽均值分别为3.15和1.40 mm,种子千粒质量均值为0.212 g,且种子具翅,种皮为黄褐色。与对照(0 mg·L-1 GA3)相比,50~200 mg·L-1 GA3处理组小溪洞杜鹃种子的萌发时滞、萌发高峰期和萌发持续时间均缩短,平均发芽速率显著减小,发芽率、发芽势和发芽指数均升高。总体来看,100 mg·L-1 GA3对小溪洞杜鹃种子萌发有明显的促进作用,而500 mg·L-1 GA3对其种子萌发有一定的抑制作用。质量体积分数5%PEG-6000处理组小溪洞杜鹃种子的萌发时滞较对照(质量体积分数0%PEG-6000)显著(p<0.05)缩短,幼苗中的可溶性蛋白质含量显著低于对照,其余指标与对照差异不显著;质量体积分数10%PEG-6000处理组仅萌发持续时间显著低于对照,其余指标与对照差异不显著;除发芽势外,质量体积分数20%PEG-6000处理组其余萌发指标均受到显著抑制。相关性分析结果显示:GA3质量浓度与小溪洞杜鹃种子的萌发高峰期和萌发持续时间分别呈极显著(p<0.01)和显著负相关,相关系数分别为-0.661和-0.554;与萌发时滞和可溶性蛋白质含量呈显著正相关,相关系数分别为0.584和0.627。PEG-6000质量体积分数与萌发时滞、萌发高峰期、平均发芽速率和可溶性蛋白质含量呈极显著正相关,相关系数分别为0.918、0.849、0.832和0.860;与发芽率和发芽指数分别呈显著和极显著负相关,相关系数分别为-0.620和-0.811。综合分析显示:小溪洞杜鹃种子具有较好的传播扩散能力。100 mg·L-1 GA3对小溪洞杜鹃种子萌发的促进作用明显,且小溪洞杜鹃种子具有一定的耐旱性,能够耐受低水平(质量体积分数5%~10%PEG-6000)的干旱胁迫。

Abstract

In order to determine the effects of gibberellin and drought stress on seed germination of Rhododendron xiaoxidongense W. K. Hu, the morphological characteristics of fruits and seeds of wild R. xiaoxidongense in Jinggang Mountain of Jiangxi were observed, the germination indexes of seeds of R. xiaoxidongense were compared under mass concentrations of 0-500 mg·L-1 gibberellin 3 (GA3) and mass volume fractions of 0%-20% polyethylene glycol6000 (PEG-6000), and Pearson correlation analysis was conducted for concentrations of GA3 and PEG-6000 and seed germination indexes. The results show that the fruits of R. xiaoxidongense are capsule, which densely covered with glandular hairs; the averages of seed length and width are 3.15 and 1.40 mm, respectively, the average of 1 000-grain mass of seeds is 0.212 g, and the seeds have wings, their episperm is yellowish brown. Compared with the control (0 mg·L-1 GA3), the germination time lag, germination peak period, and germination duration of seeds of R. xiaoxidongense in 50-200 mg·L-1 GA3 treatment groups are shortened, the average germination speed significantly decreases, and the germination rate, germination energy, and germination index increase. In general, 100 mg·L-1 GA3 has an evident promotion effect on seed germination of R. xiaoxidongense, while 500 mg·L-1 GA3 has a certain inhibitory effect on its seed germination. Compared with the control (mass volume fraction of 0% PEG-6000), the germination time lag of seeds of R. xiaoxidongense in mass volume fraction of 5% PEG-6000 treatment group is significantly (p<0.05) shortened, the soluble protein content in seedlings is significantly lower than that of the control, while the other indexes are not significantly different from those of the control; in mass volume fraction of 10% PEG-6000 treatment group, only the germination duration is significantly lower than that of the control, while the other indexes are not significantly different from those of the control;  except for germination energy, the other germination indexes in mass volume fraction of 20% PEG-6000 treatment group are significantly inhibited. The correlation analysis result shows that mass concentration of GA3 shows extremely significant and significant negative correlations with germination peak period and germination duration of seeds of R. xiaoxidongense, respectively, their correlation coefficients are -0.661 and -0.554, respectively, and shows significant positive correlations with germination time lag and soluble protein content, their correlation coefficients are 0.584 and 0.627, respectively. Mass volume fraction of PEG-6000 shows extremely significant positive correlations with germination time lag, germination peak period, average germination rate, and soluble protein content, their correlation coefficients are 0.918, 0.849, 0.832, and 0.860, respectively; it shows significant and extremely significant negative correlations with germination rate and germination index, their correlation coefficients are -0.620 and -0.811, respectively. It is suggested that R. xiaoxidongense seeds have a good dispersal ability. 100 mg·L-1 GA3 has an evident promotion effect on seed germination of R. xiaoxidongense, and R. xiaoxidongense seeds have a certain drought tolerance, which can tolerate low levels of drought stress (mass volume fractions of 5%-10% PEG-6000).

关键词小溪洞杜鹃; 形态特征; 萌发特性; 赤霉素; 干旱胁迫; Pearson相关性分析
Key wordsRhododendron xiaoxidongense W. K. Hu; morphological characteristics; germination characteristics; gibberellin; drought stress; Pearson correlation analysis
作者李丹丹1,2, 李晓花1,2, 刘杰1,2, 张乐华1,2
所在单位1. 中国科学院庐山植物园, 江西 庐山 332900; 2. 江西省植物迁地保护与利用重点实验室, 江西 九江 332015
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基金项目中国科学院科技服务网络计划(STS计划)区域重点项目(KFJ-STS-QYZD-178); 江西省自然科学基金项目(20212BAB215026)