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须弥红豆杉(Taxus wallichiana)又称为喜马拉雅红豆杉,其原变种曾称为云南红豆(Taxus yunnanensis)[1-2],是红豆杉科红豆杉属植物,有植物界的“活化石”之称,属国家一级保护植物, 1995年被濒危野生动植物物种国际贸易公约列入濒危物种[3-4]。红豆杉属植物的叶片、嫩枝、树皮、根部均含有紫杉醇成分[5],是天然的抗癌植物。广泛运用于医药领域,用于临床治疗晚期乳腺癌、肺癌、卵巢癌及头颈部癌、软组织癌和消化道癌等多种疾病[6]。目前以红豆杉为原料的生物提取方法是生产紫杉醇的重要途径,但近年来由于经济利益的驱使,红豆杉资源遭受掠夺式的开采,导致野外红豆杉种群遭受破坏严重,天然资源锐减,造成紫杉醇原料短缺的现状。须弥红豆杉是我国红豆杉属植物中紫杉醇含量最高的1种[7],其含量接近曼地亚红豆杉(Taxus media cv.'Hicksii')和欧洲红豆杉(Taxus baccata)[8],具有良好的开发利用前景。通过人工培育红豆杉是实现红豆杉资源可持续利用的重要生产手段,目前红豆杉生长速度缓慢是实现其规模化生产的主要阻力,寻找一种能有效促进红豆杉幼苗生长,缩短其生长周期的施肥方法显得尤为重要。
叶面施肥打破了土壤根部施肥的传统方式,是一种直接、高效的施肥措施,具有养分利用率高、环境污染小、针对性强、施用方法简便等特点[9]。近年来,有关红豆杉叶面施肥的研究已有报道,王琛[10]发现红豆杉叶面施氮可以促进红豆杉生物量的增长和提高其光合效率,仝川等[11]研究发现叶面喷施稀土混合肥可以明显提高了紫杉醇和10-DAB的含量且其持续作用时间较长,李志良等[12]亦有研究表明不同叶面肥处理对红豆杉枝条生长均具有促进作用。赤霉素(Gibberellin,GA)是5大类常见植物激素之一,是林木生产过程中广泛使用的植物生长调节剂,有促进植物种子萌发和幼苗生长、提前开花结果、增强植物抗逆性、提高作物产量、延缓植物衰老等作用[13-14]。大量研究表明,通过喷施外源赤霉素,可以增加作物产量[15],促进植株株高、地径、叶片的生长,促进植物根系的发育和开花结实,促进光合作用和内源激素的积累[16-18]。赤霉素在红豆杉苗木培育的应用主要集中在种子萌发、扦插育苗等方面[19-20],而对多年生苗木生理和生长的研究较少。通过对须弥红豆杉叶面喷施不同浓度的赤霉素溶液,测定须弥红豆杉生长指标及其叶片生理指标,旨在探究喷施外源赤霉素对须弥红豆杉生长和生理的影响,以期为缩短人工栽培红豆杉的生长周期提供参考。
Effects of exogenous gibberellin on growth physiological indicators of Taxus wallichiana
doi: 10.12172/202305130001
- Received Date: 2023-05-13
- Available Online: 2023-10-25
- Publish Date: 2024-02-25
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Key words:
- Taxus wallichiana /
- gibberellin /
- malondialdehyde /
- proline /
- superoxide dismutase
Abstract: In order to investigate the effects of spraying exogenous gibberellin (GA3) on the growth and physiological status of Taxus wallichiana. 5-year-old potted cuttings of Taxus wallichiana were used as experimental materials, and the leaves were sprayed with gibberellin of 0, 20, 40, 60, 80, and 100 mg·L−1 for 2 months. The plant height and ground diameter were measured regularly, and the contents of chlorophyll, malondialdehyde (MDA), proline (Pro) and superoxide dismutase (SOD) in leaves were measured at the end of the test. The results showed that: (1) With the increase of GA3 concentration, the growth of plant height and ground diameter of Taxus wallichiana showed a trend of first increasing and then decreasing, and the growth effect of 60 mg·L−1 treatment being was the best. (2) With the increase of GA3 concentration, the contents of chlorophyll a, chlorophyll b, and total chlorophyll showed a trend of first increasing and then decreasing, with the highest content of chlorophyll a and total chlorophyll was observed in the 60 mg·L−1 treatment, and the highest content of chlorophyll b was observed in the 40 mg·L−1 treatment, while the chlorophyll a content was much higher than the chlorophyll b content. (3) With the increase of GA3 concentration, the content of MDA increased first and then decreased, and the treatment of 60 mg ·L−1 was the highest, indicating the most severe stress. The contents of Pro and SOD decreased first and then increased, and both of which were the lowest in the treatment of 60 mg·L−1. In summary, the resluts showed that spraying exogenous GA3 could promote plant growth and chlorophyll accumulation during the transitional period from growth to dormancy of Taxus wallichiana. However, excessive concentration could stress the plant growth, leading to the increase of MDA content and the decrease of Pro and SOD contents in leaves, which would create stress and weaken stress resistance.