《植物生理学报》 2018, 54(3): 483-490
通信作者：沈向；E-mail: guanshangguoshu@163.com
摘 要：
研究不定根向重力性定点角(GSA)不同的苹果(Malus spp.)自根砧木在嫩枝扦插生根过程中的插穗中内源激素含量动态变化, 为通过外源激素调控不定根GSA提供理论依据。以八年生苹果‘国光’ (M. pumila cv. Ralls)与海棠(M. sp.)杂交实生苗的当年生枝条为试验材料, 于5月中旬进行嫩枝扦插, 筛选出不定根GSA不同的株系, 并于次年再次进行嫩枝扦插, 在扦插后0、8、16、24和32 d随机取插穗基部检测内源激素含量。试验结果表明: (1)按照扦插苗不定根GSA的不同, 可把苹果自根砧苗木分为3类: 30°≤GSA≤60°的不定根比例不小于50%, 且GSA<30°的不定根比例大于GSA>60°的比例的自根砧, 属于深层根型(DRT); 30°≤GSA≤60°的不定根比例不小于50%, 且GSA<30°的不定根比例小于GSA>60°的比例的自根砧, 属于中间根型(IRT); GSA>60°的不定根比例不小于50%, 且30°≤GSA≤60°的不定根比例大于GSA<30°的比例的自根砧, 属于浅层根型(SRT)。(2)在苹果自根砧嫩枝扦插生根过程中, 3种根型插穗内吲哚乙酸(IAA)含量的变化趋势呈“倒V”形, 脱落酸(ABA)和异戊烯基腺嘌呤(iPA)含量呈下降趋势, 玉米素核苷(ZR)含量呈“下降-上升-下降”的趋势; 赤霉素(GA3)含量在中间根型插穗中的变化趋势呈“倒V”形, 在深、浅层根型的则呈“V”形; 扦插16 d后, 插穗中IAA含量表现为深层根型<中间根型<浅层根型, ZR和GA3含量表现为深层根型>中间根型>浅层根型, ABA和iPA含量表现为中间根型<浅层根型<深层根型, IAA/GA3、IAA/ZR和IAA/iPA比值表现为深层根型<中间根型<浅层根型。扦插16 d后, 不定根GSA越小, 插穗中IAA含量越少, ZR和GA3含量越多, IAA/GA3、IAA/ZR和IAA/iPA比值越小。生长素是参与不定根GSA形成的主要激素, 其在从茎尖向不定根的极性运输过程中与细胞分裂素相互作用, 共同调节不定根GSA的形成。关键词：自根砧; 向重力性定点角; 嫩枝扦插; 内源激素
收稿：2017-07-10 修定：2018-01-10
资助：国家现代农业产业技术体系专项(CARS-28)、农业部科技教育司公益性行业(农业)科研专项(201303093)和支撑计划专项(2014BAD16B02)，以及山东省果品创新团队项目(sdait-06-07)。
Corresponding author: SHEN Xiang; E-mail: guanshangguoshu@163.com
Abstract:
To provide theoretical basis for the regulation of adventitious root gravitropic setpoint angle (GSA) by endogenous hormones, dynamic changes in endogenous hormone contents in cuttings of different adventitious root GSA, during rooting of softwood cuttings, was studied. The annual shoots of eight years hybrid seedlings of Malus pumila ‘Ralls’ and M. sp. were used as experimental materials, and softwood cutting was carried out in mid-May. Different strains of adventitious root GSA were screened and shoot cuttings were carried out again the following year. The cuttings were randomly selected at 0, 8, 16, 24 and 32 d after cutting, and the endogenous hormones contents of cutting bases were measured. The results show that: (1) according to the difference of adventitious root GSA of cutting seedlings, the seedlings of apple rootstock were divided into 3 groups. Rootstocks with the ratio of adventitious root (30°≤GSA≤60°) not less than 50% and the ratio of adventitious root (GSA<30°) more than the adventitious root (GSA>60°) ratio belong to the deep root type (DRT). Rootstocks with the ratio of adventitious root (30°≤GSA≤60°) not less than 50% and the ratio of adventitious root (GSA<30°) less than the adventitious root (GSA>60°) ratio belong to the intermediate root type (IRT). Rootstocks with the ratio of adventitious root (GSA>60°) not less than 50% and the adventitious root (30°≤GSA≤60°) ratio more than the ratio of adventitious root (GSA<30°) belongs to the shallow root type (SRT). (2) In the rooting process of apple rootstock softwood cuttings, changes in endogenous hormone contents in the 3 root types were as follows: indoleacetic acid (IAA) contents showed “inverted V” shape, abscisic acid (ABA) and isopentenyladenine (iPA) contents decreased continuously, and zeatin riboside (ZR) contents showed a trend of “falling-rising-falling”. As for gibberellin (GA3) content, the change trend of the IRT cuttings was “inverted V” shape, and the DRT and SRT cuttings showed “V” shape. At 16 d after cutting, the smaller the adventitious root GSA was, the less IAA content, the more ZR and GA3 content, and the smaller the ratio of IAA/GA3, IAA/ZR and IAA/iPA were. Auxin is the major hormone involved in the formation of adventitious root GSA. In the auxin polar transport process from the stem tip to the adventitious root, auxin and cytokinin interact to regulate the formation of adventitious root GSA.Key words: self-rooted rootstock; gravitropic setpoint angle; softwood cuttings; endogenous hormones
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