双断根嫁接对西瓜苗根系生长、内源激素含量及营养元素吸收的影响

梁 欢1,刘 柯1,2,葛米红1,祝菊红1,王德欢1,张昭阳1,周谟兵1,胡江勇1,施先锋1*

1武汉市农业科学院作物研究所,武汉 430345;2华中农业大学,武汉 430070)

摘 要:【目的】双断根嫁接是目前瓜类嫁接机常采用的嫁接方式。研究双断根嫁接对西瓜苗根系生长、激素含量及营养元素吸收的影响,为双断根西瓜嫁接苗水肥管理提供理论指导,同时为机械化嫁接技术的推广提供技术支持。【方法】以西瓜品种早佳84-24为接穗,南瓜品种砧壮为砧木,采用单子叶贴接法嫁接,设砧木不断根常规嫁接和双断根嫁接2个处理,测定并分析嫁接苗根系形态、根系活力、激素含量以及根系和地上部矿质元素含量等的差异。【结果】双断根嫁接使西瓜苗根直径增粗,而根长、根表面积、根体积、根尖数、根鲜质量和根干质量等显著减少;在嫁接后18 d,西瓜双断根嫁接苗的散坨率符合移栽标准,比砧木不断根常规嫁接推迟了6 d;西瓜双断根嫁接苗根系活力在嫁接初期(嫁接后12 d)显著增大,与对照相比增大了34.0%,后期无显著差异。西瓜双断根嫁接苗根系吲哚乙酸(IAA)、细胞分裂素(CTK)和乙烯(ETH)含量升高,而GA和ABA含量降低。西瓜双断根嫁接苗茎叶和根N、P、K、Fe、Mg、B含量均表现出一定程度的增加,但Ca含量均显著降低。【结论】西瓜双断根嫁接苗根系活力增强和根直径增粗,但根量不足导致易散坨,在嫁接后18 d才能达到移栽标准,比不断根推迟6 d。双断根促进N、P、K、Fe、Mg、B的吸收,但Ca的吸收减少。

关键词:西瓜嫁接苗;双断根;根系生长;激素含量;营养元素吸收

嫁接是解决西瓜连作障碍问题的有效手段,同时可增强植株对低温、盐胁迫等逆境的抗性,提高产量、改善品质,已被广泛应用于西瓜生产[1-3]。西瓜的主要嫁接方法有顶插接、靠接和单子叶贴接[4]。双断根贴接是在原有单子叶贴接的基础上,将砧木根系去掉使根系重新生长的一种新型嫁接方法,能够有效解决传统嫁接方法中秧苗生长不一致、徒长严重等问题,而且是嫁接机主要采用的嫁接方法,日益受到广泛关注[5-8]

根系是植物活跃的吸收器官和合成器官,根的生长情况和活力水平对地上部的生长有着直接影响。蒋欣梅等[8-9]研究发现双断根嫁接的番茄和辣椒苗根系活力显著提高,崔青青等[10]研究发现断根降低了嫁接接合部细胞分裂素和生长素的含量,抑制番茄嫁接愈合。根系与营养元素的吸收能力和运输效率密切相关[11-12]。相关研究发现,嫁接换根后,西瓜植株的N、K、Ca、Fe、Mg等元素的含量增高,冬瓜叶片氮、磷、钾含量分别平均提高了8.74%、31.02%和12.06%,番茄氮磷钾的吸收量平均增加27.88%、28.21%和24.23%[13-15]。双断根嫁接后,嫁接苗的根系结构发生改变。近年来,关于双断根嫁接的研究,主要集中于生产管理技术方面,如砧木品种[16]、嫁接参数[17-21]、愈合环境[21-22]、促生长[23-25]等,双断根影响嫁接苗生长的作用机制少有报道。因此,笔者在本研究中以西瓜嫁接苗为研究对象,分析双断根嫁接与砧木不断根常规嫁接对根系生长、激素含量以及营养元素吸收的影响,以期为西瓜双断根嫁接苗水肥管理提供理论指导,同时为机械化嫁接技术的推广提供技术支持。

1 材料和方法

1.1 试验材料

供试西瓜接穗品种为早佳84-24,购于新疆明鑫科鸿农业科技有限责任公司;供试南瓜砧木品种为砧壮,购于京研益农(寿光)种业科技有限公司。

1.2 试验方法

试验于2022年8月至2023年3月在武汉市农业科学研究院作物所种苗研究室的人工气候室内进行。用62.5 g·L-1精甲·咯菌腈(亮盾)悬浮种衣剂包衣后将接穗和砧木种子分别直播于填充有混合基质的98孔和72孔穴盘中,播种深度1.5 cm。播种后覆盖薄膜,置于催芽室30 ℃催芽48~72 h,待种子拱土时移入人工气候室。混合基质为草炭:珍珠岩(VV)=3∶1,加入30%恶霉灵1000 倍液和58%甲霜∙锰锌600倍液的混合液进行消毒处理。人工气候室环境条件为:温度28 ℃/18 ℃(昼/夜),光周期12 h,光照度125 μmol·m-2·s-1,空气相对湿度60%~80%。每隔3 d浇1次100 mg·L-1的水溶肥(N∶P2O5∶K2O=20∶10∶20),砧木第一枚真叶长至一分硬币大小时采用贴接法进行嫁接(播种后10 d)。

设置双断根嫁接(DRC)和砧木不断根的常规嫁接(对照)2 个处理。嫁接后嫁接苗覆盖薄膜进行愈合,愈合期管理为:温度28 ℃/18 ℃(昼/夜),光周期12 h,光照度55 μmol·m-2·s-1,空气相对湿度60%~80%。嫁接后第4 天开始揭膜,根据嫁接苗是否萎蔫调整揭膜时间,完全揭膜后调整光照度为125 μmol·m-2·s-1

1.3 测定指标

在嫁接后12、18、24 d,参考唐玉新等[26]的方法测定散坨率;使用万深根系扫描仪测定嫁接苗根长、根直径、根表面积、根尖数;使用电子天平测定根系鲜质量后,将样品放入烘箱,105 ℃杀青30 min 后,80 ℃烘干至质量恒定测定干质量;干物质研磨成粉后,参照鲍士旦[27]的方法,测定N、P、K、Ca、Mg、Fe、B等元素的含量。

采用TTC 染色法[28]测定根系活力,采用酶联免疫吸附法(Infinite F50,ELISA 检测试剂盒)测定乙烯(ETH)、吲哚乙酸(IAA)、脱落酸(ABA)、细胞分裂素(CTK)、赤霉素(GA)等激素的含量。

1.4 数据分析

采用Excel 2010 对数据进行整理,利用Origin 2019b 软件作图,采用SAS 9.4 软件ANOVA 程序对数据进行单因素方差分析,采用Duncan’s多重比较进行差异显著性分析(p<0.05)。

2 结果与分析

2.1 双断根嫁接对西瓜苗根系生长的影响

2.1.1 双断根嫁接对西瓜苗根系生长指标的影响由表1 和图1 可知,双断根西瓜苗的根直径显著增大,根长、根表面积、根体积、根尖数、根干质量均显著减少。双断根西瓜嫁接根尖数和根干质量的相对增长速率均高于常规嫁接苗,在嫁接后12~18 d,双断根西瓜嫁接苗的根尖数和根干质量分别相对增加54.45%和21.64%,比常规嫁接苗分别提高了21.09%和4.05%。双断根和常规嫁接的西瓜苗根系形态有明显差别。

图1 不同时期双断根嫁接和常规嫁接苗的根系形态
Fig.1 Observation of root growth of grafted seedlings with double-root-cutting grafting and conventional grafting in different periods

表1 不同时期双断根嫁接和常规嫁接苗的根系生长状况
Table 1 Root growth of double-root-cutting grafting and conventional grafting of grafted seedlings in different periods

注:不同小写字母代表同一时期不同处理在p<0.05 水平差异显著,下同。
Note:Different small letters indicate significant difference between different treatments at the same time(p<0.05).The same below.

时间Time/d 12 18 24根干质量Root dry mass/g 0.017 8±0.000 2 a 0.010 5±0.001 1 b 0.021 6±0.000 1 a 0.013 4±0.002 0 b 0.022 8±0.001 4 a 0.015 4±0.000 9 b处理Treatment对照Control DRC对照Control DRC对照Control DRC根长Root length/cm 268.40±23.29 a 195.79±11.94 b 514.79±20.90 a 377.97±5.37 b 610.93±15.65 a 414.80±25.01 b根表面积Root area/cm2 50.60±1.78 a 37.37±3.54 b 95.94±6.23 a 67.40±6.26 b 126.92±4.51 a 94.64±4.71 b根体积Root volume/cm3 1.43±0.01 a 1.13±0.06 b 3.66±0.31 a 2.18±0.22 b 5.28±0.13 a 4.76±0.11 b根直径Root diameter/mm 0.54±0.02 b 0.60±0.01 a 0.59±0.03 b 0.67±0.03 a 0.72±0.01 b 0.79±0.02 a根尖数Number of apex 890.00±16.37 a 447.44±29.92 b 1 335.53±21.48 a 982.39±10.78 b 1 475.50±9.82 a 1 138.78±2.59 b

2.1.2 双断根嫁接对西瓜苗散坨率的影响 散坨率表示根系成坨的程度,是移栽定植的重要评价指标,当散坨率低于20%时,幼苗满足移栽条件,可以移栽[26]。如图2 所示,嫁接后12 d,常规嫁接西瓜苗散坨率为13.3%,可以移栽;而双断根嫁接西瓜苗的散坨率为86.7%,直到嫁接后18 d,双断根嫁接西瓜苗的散坨率降为6.7%,符合移栽标准。

图2 双断根嫁接和常规嫁接对嫁接苗散坨率的影响
Fig.2 Effects of double-root-cutting grafting and conventional grafting on substrate decrease rate in grafted seedlings

2.1.3 双断根嫁接对西瓜苗根系激素含量的影响 植物激素是调控植物生长的信号分子,植物的生长发育通过激素表达水平的变化来体现[29]。由图3可知,双断根嫁接西瓜苗根系IAA、CTK和ETH含量显著升高,而GA 和ABA 含量显著降低。嫁接后12 和24 d,双断根嫁接西瓜苗根系IAA 含量分别比常规嫁接西瓜苗升高了11.5%和7.2%,CTK 含量分别升高了54.2%和19.8%,ETH 含量分别升高了24.8%和19.7%,GA 含量分别降低了19.3%和29.9%,ABA含量分别降低了52.5%和21.0%。

图3 双断根嫁接和常规嫁接对嫁接苗根系激素含量的影响
Fig.3 Effect of double-root-cutting grafting and conventional grafting on the phytohormone content in grafted seedlings

2.2 双断根嫁接对西瓜苗根系活力的影响

根系活力是反映根系生命力的重要指标,其值越高表示根系养分吸收能力越强[30]。由图4 可知,西瓜苗根系活力随着生长时间的推移,整体呈降低的趋势。在嫁接后12 d,双断根嫁接苗根系活力与对照相比增大了34.0%,且差异达显著水平,嫁接后18、24 d,双断根嫁接西瓜苗与常规嫁接西瓜苗根系活力差异不显著。

图4 双断根嫁接和常规嫁接对嫁接苗根系活力的影响
Fig.4 Effect of double-root-cutting grafting and conventional grafting on the root activity in grafted seedlings

2.3 双断根嫁接对西瓜苗养分吸收的影响

2.3.1 双断根嫁接对西瓜苗N、P、K 含量的影响由表2 可以看出,双断根嫁接西瓜苗根系和茎叶的N、K含量在嫁接后12和24 d均呈增高的趋势,除嫁接后24 d根系N含量差异不显著外,其余处理均存在显著差异。其中嫁接后12 d,双断根嫁接西瓜苗根系N、K 含量分别升高了23.8%和48.6%,茎叶N、K含量分别升高了4.7%和11.6%。双断根嫁接西瓜苗根系P含量在嫁接后12和24 d均显著升高,与常规嫁接西瓜苗相比,分别升高了7.6%和13.3%,但茎叶P 含量在嫁接后12 d 显著减少,与常规嫁接西瓜苗相比,减少了4.8%。

表2 双断根嫁接和常规嫁接苗N、P、K 含量
Table 2 The N,P,K content of grafted watermelon seedlings treated with double-root-cutting grafting and conventional grafting(g·kg-1

嫁接后时间Time after grafting/d 12 24处理Treatment对照Control DRC对照Control DRC根系Root w(N)39.12±0.32 b 48.45±0.03 a 43.75±0.28 a 44.22±0.38 a w(P)14.99±0.07 b 16.13±0.19 a 13.42±0.11 b 15.20±0.26 a w(K)31.62±0.31 b 46.98±0.47 a 27.70±0.11 b 39.21±0.56 a茎叶Shoot w(N)53.00±1.21 b 55.51±0.44 a 54.33±0.76 b 57.06±1.16 a w(P)11.50±0.19 a 10.95±0.22 a 10.73±0.06 b 12.13±0.05 a w(K)35.44±0.31 b 39.53±0.45 a 37.19±0.35 b 41.50±0.55 a

2.3.2 双断根嫁接对西瓜苗Ca、Mg含量的影响 如表3所示,双断根嫁接西瓜苗根系和茎叶Ca含量在嫁接后12和24 d均显著降低,与常规嫁接西瓜苗相比,嫁接后12 d双断根嫁接西瓜苗根系和茎叶Ca含量分别降低了68.4%和2.5%,嫁接后24 d 双断根嫁接西瓜苗根系和茎叶Ca 含量分别降低了3.4%和61.6%;双断根嫁接西瓜苗根系和茎叶Mg含量则相反,均显著增加,嫁接后12 d双断根嫁接西瓜苗根系和茎叶Mg 含量分别降低了166.7%和16.0%,嫁接后24 d双断根嫁接西瓜苗根系和茎叶Mg含量分别降低了9.1%和25.2%。

表3 双断根嫁接和常规嫁接苗Ca、Mg 含量
Table 3 The Ca,Mg content of grafted watermelon seedlings treated with double-root-cutting grafting and conventional grafting(g·kg-1

嫁接后时间Time after grafting/d 12 24处理Treatment对照Control DRC对照Control DRC根系Root w(Ca)3.58±0.06 a 1.13±0.05 b 5.24±0.07 a 5.06±0.03 b w(Mg)1.08±0.08 b 2.88±0.09 a 1.21±0.01 b 1.32±0.04 a茎叶Shoot w(Ca)8.64±0.05 a 8.43±0.01 b 8.42±0.05 a 3.24±0.08 b w(Mg)2.12±0.07 b 2.48±0.21 a 1.55±0.01 b 1.94±0.02 a

2.3.3 双断根嫁接对西瓜苗Fe、B 含量的影响 由表4 可以看出,双断根嫁接西瓜苗根系Fe 含量在嫁接后12 d显著增多,在嫁接后24 d显著减少,而双断根嫁接西瓜苗茎叶Fe 含量则相反。双断根嫁接西瓜苗根系B 含量在嫁接后12 d 显著减少,但嫁接后24 d显著增多。双断根嫁接苗茎叶B含量在嫁接后12和24 d均呈降低趋势,但嫁接后12 d双断根嫁接苗茎叶B 含量显著减少,比常规嫁接西瓜苗减少了16.3%,嫁接后24 d双断根嫁接苗茎叶B含量与常规嫁接西瓜苗无显著差异。

表4 双断根嫁接和常规嫁接苗Fe、B 含量
Table 4 The Fe,B content of grafted watermelon seedlings treated with double-root-cutting grafting and conventional grafting(mg·kg-1

嫁接后时间Time after grafting/d 12 24处理Treatment对照Control DRC对照Control DRC根系Root w(Fe)139.00±4.78 b 653.00±7.83 a 187.00±5.28 a 164.00±8.26 b w(B)28.90±0.18 a 11.00±0.36 b 13.80±0.13 b 15.80±0.23 a茎叶Shoot w(Fe)73.13±0.75 a 18.53±0.25 b 16.97±0.40 b 29.87±0.85 a w(B)24.00±0.53 a 20.10±0.85 b 37.03±0.46 a 36.03±0.58 a

3 讨 论

3.1 双断根嫁接对西瓜苗根系生长的影响

良好的根系是保证植株正常生长的必要条件[31]。常规嫁接苗根系没有受损,而断根嫁接苗的根系是愈合期重新生长的,其根系形态参数肯定低于常规嫁接苗。但新生的根系长得更快,断根嫁接苗根系干物质生长一段时间后,可达到普通嫁接苗干物质水平[32]。番茄双断根苗在嫁接后20 d根系的干鲜质量、体积、根长显著高于常规嫁接苗和自根苗[9],甜瓜双断根嫁接苗的根长、根表面积、根体积和根干质量在一叶一心期显著低于常规嫁接苗,三叶一心期与常规嫁接苗无显著差异,但双断根贴接苗在三叶一心期的根系指标仍显著低于双断根插接苗[33],西瓜双断根嫁接苗在嫁接后28 d 表现出明显的生长优势[7]。笔者在本研究中发现,西瓜双断根嫁接苗根直径增粗,但根长、根表面积、根体积、根尖数、根干质量等根系指标均减小,在嫁接后24 d,仍未达到普通嫁接苗的水平。这可能与不同嫁接方法和作物类型根系生长速度不同有关。

3.2 双断根嫁接对西瓜苗根系激素含量的影响

植株根系的生长与内源激素含量密切相关。一般认为,IAA、GA 和CTK 属于生长促进型激素,而脱落酸属生长抑制型激素。郭素娟等[34]研究发现白皮松母树插穗生根率与IAA、玉米素(ZT)、GA的含量呈正相关关系,与脱落酸的含量呈负相关关系。邹晓霞等[35]对花生(Arachis hypogaea)的研究认为,根系IAA、GA、ZT含量与根系形态特征存在显著正相关性,而ABA含量则相反。王青等[36]研究发现低浓度ABA 有利于插穗生根与生长。笔者在本研究中发现,双断根嫁接西瓜苗的根系IAA、CTK 含量升高,ABA 含量降低,这可能是植株为了满足地上部生长的需要加速双断根嫁接苗根系生长的结果,在本研究中,双断根嫁接西瓜苗的根尖数和根干质量的相对增长速率均高于常规嫁接苗也印证了这一猜测。本研究结果显示双断根嫁接西瓜苗根系GA含量降低,这可能是因为内源激素对根系生长发育的调控不仅依赖于激素的含量,更重要的是激素间的平衡。GA/ABA、IAA/ABA 与ZT/ABA 比值反映植物的生长与休止状况,比值低表明抑制型激素ABA 占优势,比值高表明促进型激素占优势,在本研究中,虽然双断根嫁接西瓜苗根系GA含量降低,但GA/ABA 的比值在嫁接后12 d 明显高于常规嫁接苗。

3.3 双断根嫁接对西瓜苗矿质元素含量的影响

叶片矿质营养主要通过根系主动吸收获得,这与根系活力、根系结构、养分吸收面积等有关。研究发现,嫁接换根后可使甜瓜叶片中P 含量提高6%~58%、N 含量提高6%~81%,使西瓜叶片N、K、Ca 和Mg含量提升12%~28%、8%~36%、13%~81%和12%~300%,但P、Fe、Zn、Mn 和Cu 含量降低[37]。Cochavi等[38]研究发现侧根和不定根的增多可以促进养分的吸收。Mccormack等[39]研究发现双断根嫁接苗的不定根系具有更高的养分和水分吸收速率。Sallaku等[40]也发现双断根嫁接苗的Ca、Fe、K、Mg、Mn的吸收速率显著增大,而常规嫁接苗仅稍微增大。双断根嫁接在嫁接时将砧木根系去掉使根系重新生长,必然对植物矿质元素含量有很大影响,主要体现在根体积、总吸收面积低于常规嫁接苗,根系活力提高,根系吸收养分能力增强。笔者在本研究中发现双断根嫁接西瓜苗N、P、K、Fe、Mg、B含量均表现出一定程度的增加,但嫁接苗茎叶P、Fe、B含量在嫁接初期显著减少,这可能与双断根嫁接造成幼苗前期生长缓慢或生长初期砧木和接穗在某些生理机能方面不协调及营养元素在植物体内的运输、移动特性有关。

笔者在本研究中发现西瓜双断根嫁接苗Ca 含量降低,这可能与养分之间的相互作用有关,研究发现,土培条件下,B 缺乏降低了番茄叶片中Ca、Mg、Fe、Cu、Zn 的浓度;然而在水培系统中,B 缺乏和过量都能促进番茄中Ca、Mg、Zn、Mn、Fe 的吸收和转运,植株对N、P、K、Mg和Ca的吸收呈现极显著的负相关关系[41]。根系结构改变可能是Ca 吸收量降低的重要原因,但具体原因有待更深入的研究。

4 结 论

双断根嫁接苗在嫁接时去掉砧木的根系,西瓜苗的根长、根表面积、根体积、根尖数、根干质量等根系指标均显著减小,移栽适期比常规嫁接西瓜苗推迟了6 d。双断根嫁接西瓜苗根系内源激素含量发生显著变化,IAA、CTK 含量升高,GA、ABA 含量降低,提高根尖数和根干质量的相对增长速率,加快根系生长,但在嫁接后24 d 仍未达到普通嫁接苗的水平。双断根嫁接苗的根直径增粗,根系活力在嫁接苗生长前期显著升高,使N、P、K、Fe、Mg、B 含量均有一定程度的升高,但降低了对Ca的吸收。基于笔者在本研究中的发现,在生产双断根嫁接苗时,可以适当添加促根物质,合理补充钙肥。

参考文献References:

[1] DAVIS A R,PERKINS-VEAZIE P,SAKATA Y,LÓPEZGALARZA S,MAROTO J V,LEE S G,HUH Y C,SUN Z Y,MIGUEL A,KING S R,COHEN R,LEE J M. Cucurbit grafting[J]. Critical Reviews in Plant Sciences,2008,27(1):50-74.

[2] BAHADUR A,SINGH P M,RAI N,SINGH A K,SINGH A K,KARKUTE S G,BEHERA T K. Grafting in vegetables to improve abiotic stress tolerance,yield and quality[J]. The Journal of Horticultural Science and Biotechnology,2024,99(4):385-403.

[3] LOUPIT G,BROCARD L,OLLAT N,COOKSON S J. Grafting in plants:Recent discoveries and new applications[J]. Journal of Experimental Botany,2023,74(8):2433-2447.

[4] DEVI P,LUKAS S,MILES C. Advances in watermelon grafting to increase efficiency and automation[J]. Horticulturae,2020,6(4):88.

[5] BALLIU A,SALLAKU G,ISLAMI E. Root pruning effects on seedlings’growth and plant stand establishment rate of watermelon grafted seedlings[J].Acta Horticulturae,2014(1033):19-24.

[6] GUAN W J,ZHAO X.Effects of grafting methods and root excision on growth characteristics of grafted muskmelon plants[J].HortTechnology,2015,25(6):706-713.

[7] 刘叶琼,赵彬,汤伟华,冯英娜,孙朋朋,蔡善亚.不同嫁接方法对西瓜幼苗生长的影响[J]. 江苏农业科学,2020,48(19):134-137.LIU Yeqiong,ZHAO Bin,TANG Weihua,FENG Yingna,SUN Pengpeng,CAI Shanya.Effects of different grafting methods on growth of watermelon seedlings[J]. Jiangsu Agricultural Sciences,2020,48(19):134-137.

[8] 蒋欣梅,田雪,陈映彤,张雪,吴凤芝,于锡宏.双断根嫁接对辣椒嫁接苗愈合及生长的影响[J].北方园艺,2021(2):10-16.JIANG Xinmei,TIAN Xue,CHEN Yingtong,ZHANG Xue,WU Fengzhi,YU Xihong. Effects of both-root-cut grafting on the wound healing and growth of grafting seedling of pepper[J].Northern Horticulture,2021(2):10-16.

[9] 蒋欣梅,王波,于锡宏,吴凤芝,张修国,杨光鹏,王欣.双断根套管嫁接方法对番茄苗愈合及根系再生的影响[J].东北农业大学学报,2017,48(9):21-27.JIANG Xinmei,WANG Bo,YU Xihong,WU Fengzhi,ZHANG Xiuguo,YANG Guangpeng,WANG Xin. Effect of both-rootcut tube grafting method on coalscence responses and root regenerated of tomato seeding[J]. Journal of Northeast Agricultural University,2017,48(9):21-27.

[10] 崔青青,孟宪敏,段韫丹,庄团结,董春娟,高丽红,尚庆茂.断根与打顶对番茄嫁接愈合的抑制作用[J]. 中国农业科学,2022,55(2):365-377.CUI Qingqing,MENG Xianmin,DUAN Yundan,ZHUANG Tuanjie,DONG Chunjuan,GAO Lihong,SHANG Qingmao.Inhibiting effect of root-cutting and top-pinching on graft healing of tomato[J].Scientia Agricultura Sinica,2022,55(2):365-377.

[11] 郑丽,樊剑波,何园球,郑学博,许小伟.不同供磷水平对旱作条件下水稻生长、根系形态和养分吸收的影响[J].土壤,2015,47(4):664-669.ZHENG Li,FAN Jianbo,HE Yuanqiu,ZHENG Xuebo,XU Xiaowei. Effects of phosphorus on growth,root morphology,phosphorus uptake and utilization efficiency of rice seedlings[J].Soils,2015,47(4):664-669.

[12] 张晓英,梁新书,张振贤,佟二建,高丽红.异根嫁接对黄瓜适度水分亏缺下营养生长和养分吸收的影响[J].中国农业大学学报,2014,19(3):137-144.ZHANG Xiaoying,LIANG Xinshu,ZHANG Zhenxian,TONG Erjian,GAO Lihong. Influence of grafting on cucumber growth and nutrient absorption under water-deficient condition[J]. Journal of China Agricultural University,2014,19(3):137-144.

[13] HUANG Y,ZHAO L Q,KONG Q S,CHENG F,NIU M L,XIE J J,MUHAMMAD A N,BIE Z L. Comprehensive mineral nutrition analysis of watermelon grafted onto two different rootstocks[J].Horticultural Plant Journal,2016,2(2):105-113.

[14] 廖道龙,张文,王小娟,云天海,胡艳平,陈贻诵.嫁接冬瓜干物质以及氮、磷、钾养分累积与分配特性研究[J].热带作物学报,2021,42(3):754-760.LIAO Daolong,ZHANG Wen,WANG Xiaojuan,YUN Tianhai,HU Yanping,CHEN Yisong. Dry matter and nutrient accumulation and distribution characteristics of N,P and K in grafted wax gourd[J]. Chinese Journal of Tropical Crops,2021,42(3):754-760.

[15] 袁亭亭,宋小艺,王忠宾,杨建平,徐坤.嫁接与施肥对番茄产量及氮、磷、钾吸收利用效率的影响[J].植物营养与肥料学报,2011,17(1):131-136.YUAN Tingting,SONG Xiaoyi,WANG Zhongbin,YANG Jianping,XU Kun. Effect of grafting cultivation and fertilization on the yield,NPK uptake and utilization of tomatoes[J].Plant Nutrition and Fertilizer Science,2011,17(1):131-136.

[16] 任慧转,周海姣,尧甜,潘文博,丁明.不同砧木对西瓜断根嫁接苗生长发育的影响[J].中国瓜菜,2024,37(7):107-110.REN Huizhuan,ZHOU Haijiao,YAO Tian,PAN Wenbo,DING Ming.Effects of different rootstocks on the growth and development of root-cutting grafted watermelon seedlings[J]. China Cucurbits and Vegetables,2024,37(7):107-110.

[17] 丁晓晨,李梦竹,丰崇然,别之龙,成金桃.砧穗生理苗龄对断根贴接薄皮甜瓜幼苗质量的影响[J].中国瓜菜,2023,36(12):64-70.DING Xiaochen,LI Mengzhu,FENG Chongran,BIE Zhilong,CHENG Jintao. Effects of rootstock and scion physiological seedling age on the quality of oriental melon root-cut splice grafted seedlings[J]. China Cucurbits and Vegetables,2023,36(12):64-70.

[18] 陈昊,王波,毛同艳,张倩,雷杨,蒋欣梅.砧木、接穗不同苗龄对茄子双断根嫁接苗愈合及根系再生的影响[J].长江蔬菜,2018(12):17-20.CHEN Hao,WANG Bo,MAO Tongyan,ZHANG Qian,LEI Yang,JIANG Xinmei. Effects of stock and scion with different seedling age on concrescence and root regeneration of double root-cutting grafting eggplant seedlings[J]. Journal of Changjiang Vegetables,2018(12):17-20.

[19] 方伟,张青,孙永生.砧木插入基质深度对黄瓜双断根嫁接苗前期生长的影响[J].北方园艺,2016(16):50-52.FANG Wei,ZHANG Qing,SUN Yongsheng. Effect of depth of rootstock inserted matrix on early growth of cucumber seedling by double-root-cut grafting pattern[J]. Northern Horticulture,2016(16):50-52.

[20] 方伟,张青,惠成章,刘爱群.接穗不同切面长度对黄瓜双断根嫁接苗前期生长的影响[J].北方园艺,2016(10):38-40.FANG Wei,ZHANG Qing,HUI Chengzhang,LIU Aiqun. Effect of different facets length scion on the early growth of grafted cucumber double uprooting seedling[J]. Northern Horticulture,2016(10):38-40.

[21] 王芽芽,张帆,石玉,鲍恩财,曹凯,吴雪,张毅.不同R/FR 比值对双断根西瓜嫁接苗生理及光合荧光特性的影响[J].中国农业大学学报,2024,29(3):87-98.WANG Yaya,ZHANG Fan,SHI Yu,BAO Encai,CAO Kai,WU Xue,ZHANG Yi.Effects of different R/FR ratios on physiological and photosynthetic fluorescence characteristics of double-rootcutting grafted watermelon seedlings[J]. Journal of China Agricultural University,2024,29(3):87-98.

[22] 刘方园,黄远,万正杰,黎煊,孔秋生,别之龙.不同温度和光照处理对西瓜嫁接苗生长的影响[J].北方园艺,2016(2):1-5.LIU Fangyuan,HUANG Yuan,WAN Zhengjie,LI Xuan,KONG Qiusheng,BIE Zhilong. Effect of different temperature and light combination treatments on the growth of grafted watermelon seedlings[J].Northern Horticulture,2016(2):1-5.

[23] 吴帼秀,吴长江,董垚欣,牛旭旭,李阳,李严曼,李胜利.外源H2S 对番茄双断根嫁接砧木及嫁接苗生长的影响[J].中国蔬菜,2023(3):65-72.WU Guoxiu,WU Changjiang,DONG Yaoxin,NIU Xuxu,LI Yang,LI Yanman,LI Shengli. Effects of exogenous H2S on growth of tomato double-root-cutting grafted rootstocks and seedlings[J].China Vegetables,2023(3):65-72.

[24] BALLIU A,SALLAKU G.Exogenous auxin improves root morphology and restores growth of grafted cucumber seedlings[J].Horticultural Science,2017,44:82-90.

[25] JEONG H W,LEE H R,KIM J Y,KIM G G,NA C I,HWANG S J.Assessment of growing media and fertigation for production of root pruning splice-grafted cucumber seedlings[J]. Korean Journal of Horticultural Science and Technology,2021,39(3):294-304

[26] 唐玉新,曲萍,陆岱鹏,李辉,易中懿.适合机械化移栽的番茄穴盘育苗基质配方筛选[J].江苏农业学报,2017,33(6):1342-1348.TANG Yuxin,QU Ping,LU Daipeng,LI Hui,YI Zhongyi.Screening of tomato plug seedling substrates proportion suitable for mechanized transplanting[J]. Jiangsu Journal of Agricultural Sciences,2017,33(6):1342-1348.

[27] 鲍士旦. 土壤农化分析[M]. 3 版. 北京:中国农业出版社,2000.BAO Shidan. Soil and agricultural chemistry analysis[M]. 3rd ed.Beijing:China Agriculture Press,2000.

[28] 邓永兴,王文亮,周苏玫,詹克慧,徐利利,付锦州,郭芳芳,韩亚倩,杨习文,贺德先.小麦根际解钾微生物与土壤钾含量、钾素利用率及根系活力的关系[J]. 植物营养与肥料学报,2021,27(6):1027-1043.DENG Yongxing,WANG Wenliang,ZHOU Sumei,ZHAN Kehui,XU Lili,FU Jinzhou,GUO Fangfang,HAN Yaqian,YANG Xiwen,HE Dexian. Relationships of potassium-releasing rhizosphere microorganisms with soil potassium content,potassium use efficiency and root vigor in wheat (Triticum aestivum L.)[J].Journal of Plant Nutrition and Fertilizers,2021,27(6):1027-1043.

[29] 彭澳林,郑蓉,舒波,罗纯.园艺植物果实大小调控机制研究进展[J/OL]. 分子植物育种,2025:1-20. (2025-01-07)[2025-01-13].https://link.cnki.net/urlid/46.1068.S.20250107.1530.006.PENG Aolin,ZHENG Rong,SHU Bo,LUO Chun. Research progress on molecular regulation of fruit size in horticultural plants[J/OL].China Industrial Economics,2025:1-20.(2025-01-07) [2025- 01- 13].https://link.cnki.net/urlid/46.1068.S.20250107.1530.006.

[30] ZHANG Z H,LIU Y,CAO B L,CHEN Z J,XU K. The effectiveness of grafting to improve drought tolerance in tomato[J].Plant Growth Regulation,2020,91(1):157-167.

[31] LESKOVAR D I,STOFFELLA P J.Vegetable seedling root systems:Morphology,development,and importance[J]. Hort-Science,1995,30(6):1153-1159.

[32] BABAJ I,SALLAKU G,BALLIU A. Splice grafting versus root pruning splice grafting:Stand establishment and productivity issues in Cucurbitacea vegetables[J].Journal of Food Agriculture&Environment,2014,12:165-168.

[33] 刘明,李梦竹,孙齐宇,黄远,别之龙.四种嫁接方法对甜瓜嫁接苗生长的影响[J].北方园艺,2021(4):40-45.LIU Ming,LI Mengzhu,SUN Qiyu,HUANG Yuan,BIE Zhilong. Effects of four grafting methods on the growth of melon seedlings[J].Northern Horticulture,2021(4):40-45.

[34] 郭素娟,凌宏勤,潘万春,李凤兰.白皮松插穗的生根特性与其解剖构造的关系[J].北京林业大学学报,2004,26(5):43-46.GUO Sujuan,LING Hongqin,PAN Wanchun,LI Fenglan. Relationship between rooting characteristics and anatomical structure of Pinus bungeana cuttings[J]. Journal of Beijing Forestry University,2004,26(5):43-46.

[35] 邹晓霞,张晓军,王铭伦,王月福.土壤容重对花生根系生长性状和内源激素含量的影响[J].植物生理学报,2018,54(6):1130-1136.ZOU Xiaoxia,ZHANG Xiaojun,WANG Minglun,WANG Yuefu.Effects of soil bulk density on root growth traits and endogenous hormones contents in peanut (Arachis hypogaea)[J]. Plant Physiology Journal,2018,54(6):1130-1136.

[36] 王青,张捷,仲崇禄,张勇,魏永成,孟景祥.麻楝扦插生根进程中内源激素和营养物质含量的变化[J].中南林业科技大学学报,2020,40(4):111-119.WANG Qing,ZHANG Jie,ZHONG Chonglu,ZHANG Yong,WEI Yongcheng,MENG Jingxiang. Variation of endogenesis hormone and nutritive matter concentration in Chukrasia tabularis cuttings during rooting[J].Journal of Central South University of Forestry&Technology,2020,40(4):111-119.

[37] NAWAZ M A,IMTIAZ M,KONG Q S,CHENG F,AHMED W,HUANG Y,BIE Z L. Grafting:A technique to modify ion accumulation in horticultural crops[J]. Frontiers in Plant Science,2016,7:1457.

[38] COCHAVI A,COHEN I H,RACHMILEVITCH S. The role of different root orders in nutrient uptake[J]. Environmental and Experimental Botany,2020,179:104212.

[39] MCCORMACK M L,DICKIE I A,EISSENSTAT D M,FAHEY T J,FERNANDEZ C W,GUO D L,HELMISAARI H S,HOBBIE E A,IVERSEN C M,JACKSON R B,LEPPÄLAMMI-KUJANSUU J,NORBY R J,PHILLIPS R P,PREGITZER K S,PRITCHARD S G,REWALD B,ZADWORNY M. Redefining fine roots improves understanding of below-ground contributions to terrestrial biosphere processes[J]. New Phytologist,2015,207(3):505-518.

[40] SALLAKU G,SANDÉN H,BABAJ I,KACIU S,BALLIU A,REWALD B. Specific nutrient absorption rates of transplanted cucumber seedlings are highly related to RGR and influenced by grafting method,AMF inoculation and salinity[J].Scientia Horticulturae,2019,243:177-188.

[41] 刘玲,段贤杰,徐芳森,汪社亮.植物硼高效吸收利用调控生长的研究进展[J]. 华中农业大学学报(自然科学版),2022,41(2):1-8.LIU Ling,DUAN Xianjie,XU Fangsen,WANG Sheliang.Progress on growth regulation of high boron efficiency absorption,utilization in plants[J].Journal of Huazhong Agricultural University(Natural Science Edition),2022,41(2):1-8.

Effects of double-root-cutting grafting on root growth,endogenous hormone content and nutrient uptake in watermelon seedlings

LIANG Huan1, LIU Ke1,2, GE Mihong1, ZHU Juhong1, WANG Dehuan1, ZHANG Zhaoyang1, ZHOU Mobing1,HU Jiangyong1,SHI Xianfeng1*
(1Institute of Crop, Wuhan Academy of Agricultural Sciences, Wuhan 430345, Hubei, China;2Huazhong Agricultural University, Wuhan 430070,Hubei,China)

Abstract:【Objective】Grafting has many advantages,such as increasing yield,improving nutrition and water uptake,and raising resistance to soil-borne diseases and damage caused by biotic or abiotic stressors. It has become a common practice in watermelon.Although the utilization of watermelon grafting has been steadily increasing over time and 95%of commercial watermelon productions actually rely on it in some regions of the world, the higher cost of grafted watermelon transplants is still one of the primary factors limiting application in regions with medium and large-scale production.The labor-efficient automation of grafting has been recognized as a key factor in the wider adoption of grafting.In growing cucurbits, the root-one-cotyledon-removing grafting method is the most commonly used with grafting machines. For root-cutting-one-cotyledon grafting method, root development is an important factor for seedling quality. Because acquiring strong roots is the main purpose for grafting, it is important to understand the root development of grafted seedlings. However, there is little information on the root growth of root-cutting grafted seedlings.In order to apply this grafting technology efficiently,the influence of root-cutting grafting on the root growth and mineral nutrient absorption of watermelon seedlings was studied.【Methods】The watermelon variety Zaojia 84-24 was used as the scion, and the pumpkin variety Zhenzhuang was used as the rootstock.The scion and rootstock seeds were respectively sown into 98- and 72-cell trays with one seed in one cell filled with mixed seedling substrate (peat moss and pearlite at a volume ratio of 3∶1). The seeds of rootstock and scion were sown on the same day to meet the requirements for grafting experiments.The plants were cultivated in an artificial chamber with a day/night (12 h/12 h) cycle at 28 ℃/18 ℃with 60%-80% relative humidity. Grafting was performed after the first true leaf developed on the rootstock and scion at 10th day after sowing.When grafting,the seedlings were divided into two groups.One group was grafted using root-cutting-one-cotyledon grafting method (DRC).After grafting, the plants were transplanted into 72-cell tray-plug with mixed seedling substrate.The other group was grafted using one-cotyledon splice grafting method(CK),in that rootstock had intact root system. The grafted seedlings were placed under a plastic film with a day/night cycle at 28 ℃/18 ℃with more than 90%humidity under low light intensity(75 μmol·m-2·s-1,12 h/12 h photoperiod) for healing. The grafted plants were exposed to the air 1-3 h per day until the scions were alive and grew.After the healing process,the root growth parameters such as root morphology indexes, root activity and scattered lump rate were measured at 6-day interval.At the same time,samples were also harvested for examining the hormone and mineral contents.【Results】The root diameter of grafted watermelon seedlings with pumpkin root-cutting was thick while the root length,root surface area, root volume, root tip number, root fresh weight and root dry weight were significantly reduced.The scattering lump rate of grafted watermelon seedlings with pumpkin root-cutting was 86.7%while the scattering rate of grafted watermelon seedlings with the control was only 13.3% on the 12th day after grafting.The contents of IAA,CTK and ETH in the root of grafted watermelon seedlings with pumpkin root-cutting significantly increased while the contents of GA and ABA significantly decreased.The contents of N, P, K, Mg, Fe and B in stems and roots of grafted watermelon seedlings with pumpkin root-cutting showing a certain degree of increase.However,the contents of Ca in stems and roots of grafted watermelon seedlings with pumpkin root-cutting decreased significantly.【Conclusion】A welldeveloped root system induced vigorous stem growth and plant development,and root growth was also influenced by stem. The root of watermelon seedlings grafted by root-cutting grafting method was regenerated with adventitious roots.The regenerated root system had higher root activity and mineral absorption capacity. The contents of N, P, K, Fe, Mg and B increased in grafted watermelon seedlings with pumpkin root-cutting.At the same time, the seedlings increased the IAA, CTK and ETH contents of root to promote the root growth. However, the seedlings by using this grafting method had not enough root system at the early stage,which decreased the accumulation of mineral elements.The content of Ca was reduced in grafted watermelon seedlings with pumpkin root-cutting,which may be related to the difference in root architecture,but further research is needed to understand the decrease of Ca absorption. The results of this study can provide theoretical guidance for the fertilizer management of watermelon grafting seedlings, and promote the popularization and application of mechanized grafting technology.

Key words:Grafted watermelon seedlings;Double-root-cutting;Root growth;Hormone content;Nutrient absorption

中图分类号:S651

文献标志码:A

文章编号:1009-9980(2025)04-0864-10

DOI:10.13925/j.cnki.gsxb.20240435

收稿日期:2024-09-05

接受日期:2025-02-07

基金项目:湖北省重点研发计划(2023BBB033);武汉市科技计划项目(2023110201030690);武汉市知识创新专项曙光项目(2022020801020418)

作者简介:梁欢,女,农艺师,硕士,研究方向为蔬菜苗期发育调控。Tel:027-65388593,E-mail:lianghuanconf@126.com

*通信作者Author for correspondence. E-mail:821648773@qq.com