香芹酮对马铃薯种薯发芽的调控机制

【目的】香芹酮是植物精油中常见的单萜类物质。从激素调控和膜脂过氧化方面探讨香芹酮对马铃薯种薯发芽调控的作用机制,为其在种薯上的实际应用提供理论依据。【方法】以‘青薯9号’微型薯为试验材料,采用香芹酮0.3 mL·kg^-1(药剂体积/块茎重量)的处理剂量,贮藏18周后进行停药6周的处理方式,同时以不做任何处理为对照,分别在贮藏0、6、18、20和24周,测定种薯芽长、失重率、脱落酸(ABA)、吲哚乙酸(IAA)、赤霉素(GA₃)、丙二醛(MDA)和脯氨酸(PRO)的含量,超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、过氧化物酶(POD)和多酚氧化酶(PPO)的活性,并定期对种薯芽分生组织进行切片和显微成像分析。【结果】香芹酮可调控种薯的发芽和芽长,降低种薯的失重率,贮藏24周时,处理种薯芽长为4.77 mm,显著低于对照芽长51.02 mm,且失重率比对照降低49.76%。香芹酮通过损伤种薯顶芽分生组织和维管束组织抑制顶芽的生长,但不影响腋芽的萌出。贮藏期间,香芹酮显著提高了种薯中ABA的含量,但抑制了IAA的含量,推迟了GA₃

Regulation Mechanism of Carvone on Seed Potato Sprouting

【Objective】 Carvone is a common monoterpene in plant essential oils. In this study, the partial regulation mechanism of carvone on seed potato sprouting was explored from the aspects of hormone regulation and membrane lipid peroxidation. 【Method】The cultivar Qingshu 9 was used as experimental material. The method of treatment was using 0.3 mL carvone per kilogram of tuber for 18 weeks, and then stopping chemical for 6 weeks before planting. At the same time, the treatment without using carvone was as control group. Sprout length, weight loss, abscisic acid (ABA), indoleacetic acid (IAA), gibberellic acid (GA₃), malondialdehyde (MDA) and proline (PRO) contents, superoxide dismutase (SOD), catalase (CAT), polyphenol oxidase (PPO) and peroxidase (POD) enzyme activities were determined under different storage periods (at 0, 6, 18, 20 and 24 week). Meanwhile, the bud meristem of seed potato was sectioned and analyzed by microimaging regularly. 【Result】 Carvone treatment could regulate potato sprouting and the sprout length, and reduce the weight loss of seed potatoes. After 24 weeks of storage, the sprout length of the treated seed potatoes was 4.77 mm, significantly lower than that of the control group (51.02 mm), and the weight loss was reduced by 49.76%. Carvone treatment inhibited the growth of apical buds by damaging apical meristem and vascular tissue, which did not affect the emergence of axillary buds. During storage, carvone treatment significantly increased the ABA content, inhibited the IAA content, delayed the peak of GA₃ content and the appearance of (GA₃+IAA) /ABA >1 inflection point. For the carvone reated potatoes, MDA content in potato was 15.04%-25.90% lower than control group; PRO content was 24.59%-54.45% higher than control group; the activities of SOD, CAT and PPO were 18.86%-35.56%, 14.34%-31.97% and 26.00%-36.41% higher than control group, respectively; POD activity of treated potatoes was 1.87-3.07 times that of control group. 【Conclusion】 Carvone treatment adjusted the ABA, IAA and GA₃ contents of seed potatoes by promoting/inhibiting 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMG-CoA reductase) in the mevalonate pathway, and regulated the inhibition of the apical bud. In addition, it increased antioxidant enzymes activities, reduced the degree of membrane lipid peroxidation and alleviated seed potato aging.