CAJ | 학술논문

薇甘菊Mikania micrantha Kunth为原产中南美洲的入侵藤本植物，现已在全球热带和亚热带地区照成严重的生态问题。野外观察发现薇甘菊已在珠三角沿海植被中滋生。为揭示薇甘菊的耐盐能力及其对滨海盐生植被的潜在危害性，分别对薇甘菊种子、根系和茎干在不同盐度胁迫下的响应进行了测定。在珠三角地区采集了薇甘菊3个批次的种子，并选取珠江三角洲6种常见植物（菊科假臭草Eupatorium catarium、藿香蓟Ageratum conyzoides、野茼蒿Crassocephalum crepidioides、鬼针草Bidens pilosa、翅果菊Pterocypsela indica和旋花科小花假番薯Ipomoea triloba）作为对照，测定了它们在不同NaCl盐度（质量分数）胁迫下的萌发率和幼苗生长；为揭示薇甘菊种子是否可由海水传播，将薇甘菊和对照植物假臭草、藿香蓟和鬼针草在不同盐度条件下浸泡不同时间后解除胁迫再观测其种子萌发率；为确定薇甘菊能否在滨海盐土中无性繁殖，分别对薇甘菊的根系和茎干在盐水浸泡下的植株生长进行了测定。研究结果表明：1）总体而言，薇甘菊3个种群在≤0.6%盐度胁迫下的种子萌发率均与对照组无显著差异，个别种群的这一阈值可高达1.5%，明显高于其他对照植物；同一盐度胁迫条件下，薇甘菊幼苗根系和苗高生长受抑制程度明显低于对照植物。2）即使经高达3.0%盐度胁迫浸泡长达12 d后，薇甘菊、藿香蓟和假臭草种子的萌发率也没有受到显著影响，而鬼针草种子的萌发率有明显下降；四种植物受浸泡后萌芽的幼苗生长均正常。3）薇甘菊根系受0.5%盐度胁迫时没有植株死亡，但苗高增长仅为对照组的53.3%；根系在1.0%盐度胁迫下有95%的植株能存活至少25 d，但苗高增长仅为对照的18.9%；根系在≥1.5%盐度胁迫下薇甘菊无法存活。4）被清水浸泡的薇甘菊茎茎叶均能存活且在全部被浸泡的节上萌芽。当薇甘菊茎干受≥1.0%盐水浸泡时，受浸泡的叶片全部死亡，在1.0%、2.0%和3.0%盐度胁迫下受试茎第21天的死亡率分别为42.9%、40.9%和86.4%。以上结果表明薇甘菊对盐生生境具一定的适应能力，可能通过种子萌发或无性繁殖扩张的方式对滨海盐生植被构成威胁，应当引起重视。薇甘菊Mikania micrantha Kunth為原產中南美洲的入侵籐本植物，現已在全毬熱帶和亞熱帶地區照成嚴重的生態問題。野外觀察髮現薇甘菊已在珠三角沿海植被中滋生。為揭示薇甘菊的耐鹽能力及其對濱海鹽生植被的潛在危害性，分彆對薇甘菊種子、根繫和莖榦在不同鹽度脅迫下的響應進行瞭測定。在珠三角地區採集瞭薇甘菊3箇批次的種子，併選取珠江三角洲6種常見植物（菊科假臭草Eupatorium catarium、藿香薊Ageratum conyzoides、野茼蒿Crassocephalum crepidioides、鬼針草Bidens pilosa、翅果菊Pterocypsela indica和鏇花科小花假番藷Ipomoea triloba）作為對照，測定瞭它們在不同NaCl鹽度（質量分數）脅迫下的萌髮率和幼苗生長；為揭示薇甘菊種子是否可由海水傳播，將薇甘菊和對照植物假臭草、藿香薊和鬼針草在不同鹽度條件下浸泡不同時間後解除脅迫再觀測其種子萌髮率；為確定薇甘菊能否在濱海鹽土中無性繁殖，分彆對薇甘菊的根繫和莖榦在鹽水浸泡下的植株生長進行瞭測定。研究結果錶明：1）總體而言，薇甘菊3箇種群在≤0.6%鹽度脅迫下的種子萌髮率均與對照組無顯著差異，箇彆種群的這一閾值可高達1.5%，明顯高于其他對照植物；同一鹽度脅迫條件下，薇甘菊幼苗根繫和苗高生長受抑製程度明顯低于對照植物。2）即使經高達3.0%鹽度脅迫浸泡長達12 d後，薇甘菊、藿香薊和假臭草種子的萌髮率也沒有受到顯著影響，而鬼針草種子的萌髮率有明顯下降；四種植物受浸泡後萌芽的幼苗生長均正常。3）薇甘菊根繫受0.5%鹽度脅迫時沒有植株死亡，但苗高增長僅為對照組的53.3%；根繫在1.0%鹽度脅迫下有95%的植株能存活至少25 d，但苗高增長僅為對照的18.9%；根繫在≥1.5%鹽度脅迫下薇甘菊無法存活。4）被清水浸泡的薇甘菊莖莖葉均能存活且在全部被浸泡的節上萌芽。噹薇甘菊莖榦受≥1.0%鹽水浸泡時，受浸泡的葉片全部死亡，在1.0%、2.0%和3.0%鹽度脅迫下受試莖第21天的死亡率分彆為42.9%、40.9%和86.4%。以上結果錶明薇甘菊對鹽生生境具一定的適應能力，可能通過種子萌髮或無性繁殖擴張的方式對濱海鹽生植被構成威脅，應噹引起重視。
미감국Mikania micrantha Kunth위원산중남미주적입침등본식물，현이재전구열대화아열대지구조성엄중적생태문제。야외관찰발현미감국이재주삼각연해식피중자생。위게시미감국적내염능력급기대빈해염생식피적잠재위해성，분별대미감국충자、근계화경간재불동염도협박하적향응진행료측정。재주삼각지구채집료미감국3개비차적충자，병선취주강삼각주6충상견식물（국과가취초Eupatorium catarium、곽향계Ageratum conyzoides、야동호Crassocephalum crepidioides、귀침초Bidens pilosa、시과국Pterocypsela indica화선화과소화가번서Ipomoea triloba）작위대조，측정료타문재불동NaCl염도（질량분수）협박하적맹발솔화유묘생장；위게시미감국충자시부가유해수전파，장미감국화대조식물가취초、곽향계화귀침초재불동염도조건하침포불동시간후해제협박재관측기충자맹발솔；위학정미감국능부재빈해염토중무성번식，분별대미감국적근계화경간재염수침포하적식주생장진행료측정。연구결과표명：1）총체이언，미감국3개충군재≤0.6%염도협박하적충자맹발솔균여대조조무현저차이，개별충군적저일역치가고체1.5%，명현고우기타대조식물；동일염도협박조건하，미감국유묘근계화묘고생장수억제정도명현저우대조식물。2）즉사경고체3.0%염도협박침포장체12 d후，미감국、곽향계화가취초충자적맹발솔야몰유수도현저영향，이귀침초충자적맹발솔유명현하강；사충식물수침포후맹아적유묘생장균정상。3）미감국근계수0.5%염도협박시몰유식주사망，단묘고증장부위대조조적53.3%；근계재1.0%염도협박하유95%적식주능존활지소25 d，단묘고증장부위대조적18.9%；근계재≥1.5%염도협박하미감국무법존활。4）피청수침포적미감국경경협균능존활차재전부피침포적절상맹아。당미감국경간수≥1.0%염수침포시，수침포적협편전부사망，재1.0%、2.0%화3.0%염도협박하수시경제21천적사망솔분별위42.9%、40.9%화86.4%。이상결과표명미감국대염생생경구일정적괄응능력，가능통과충자맹발혹무성번식확장적방식대빈해염생식피구성위협，응당인기중시。
Mikania micrantha Kunth is a noxious invasive species in tropical and subtropical regions. This weed has been found to grow on the coast of the Pearl River Delta and off-coast islands in China. In the present study, we assessed the salt tolerance of M. micrantha seeds, roots, and stems separately. Seed germination and seedling growth in different concentrations of NaCl were tested for three M. micrantha populations and six common species (Eupatorium catarium, Ageratum conyzoides, Crassocephalum crepidioides, Bidens pilosa, Pterocypsela indica, and Ipomoea triloba) in the Pearl River Delta. Seed germination of M. micrantha, E. catarium, A. conyzoides, and B. pilosa were tested after 3, 6, and 12 days of submergence in different concentrations of NaCl to determine whether seeds can be transferred by seawater. Responses of submerged cultured M. micrantha root and stem in different concentrations of NaCl were also recorded to determine whether the weed can disperse by vegetative propagation in coastal saline soils. Experiments produced the following results. 1) In general, the seed germination rates of M. micrantha did not differ significantly from those of the controls at ≤0.6% salinity, and the highest threshold value of 1.5% was greater than those for all control species. Radicle and seedling height growth rates of M. micrantha were less suppressed than those of control plants under the same salinity stress. 2) In comparison with controls, no significant decline in germination rate was observed in treated (submerged in up to 3.0%NaCl for up to 12 days) M. micrantha, A. conyzoides, or E. catarium, whereas submergence in 3.0%NaCl for 12 days caused a significant decline in B. pilosa. However, seedlings of all four tested species grew well. 3) All tested M. micrantha plants survived 0.5%salinity stress to root systems, with a decline in the average seedling height growth rate to 53.3%those of controls;95%of tested plants survived up to 1.0%salinity stress to root systems for at least 25 days, with a decline in the average seedling height growth rate to 18.9%;no M. micrantha plant survived 1.5%salinity stress to the root system. 4) All leaves of M. micrantha survived stem submergence in water, with sprouting observed in all submerged nodes, whereas all submerged leaves died when stems were exposed to ≥1.0%salinity stress. Mortality rates of the tested stems at day 21 were 42.9%, 40.9%, and 86.4%for 1.0%, 2.0%, and 3.0% salinity stress, respectively. We conclude that M. micrantha can disperse in coastal saline soils by seed and vegetative propagation. More attention should be paid to the potential threat of M. micrantha populations near coastal halophytic vegetation.