黄菊对油茶林2种杂草萌发和幼苗生长的化感作用

【目的】探究黄菊对杂草的化感作用,为降低油茶林除草成本、增加效益提供参考。【方法】选取白茅和狗尾草作为受体,采用培养皿滤纸法进行种子萌发试验,以黄菊茎叶和根际土不同质量浓度浸提液处理受体种子,测定各处理下种子萌发指标和幼苗生长指标。【结果】黄菊根际土浸提液对白茅种子萌发表现为低质量浓度(≤0.02 g/mL)促进、高质量浓度(≥0.06 g/mL)抑制,而对狗尾草种子萌发均表现为抑制作用。0.02、0.06、0.10 g/mL根际土浸提液对白茅幼苗鲜质量、干质量、苗高和根长4个指标均表现为促进作用,但对其鲜质量和苗高的影响表现出随质量浓度升高促进作用减弱的趋势,而对其干质量和根长的影响表现为随质量浓度升高促进作用增强,在0.1 g/mL处理组中干质量和根长达到最大,分别显著高出对照29.94%和53.74%(P <0.05)。根际土浸提液对狗尾草干质量和根长的影响规律与对白茅的影响相同,在0.1 g/mL处理组中分别高出对照47.67%(P <0.05)和6.59%,但其对狗尾草鲜质量和苗高的影响表现为"低抑高促"。0.02、0.06、0.10 g/mL黄菊茎叶浸提液对2种受体种子的萌发均表现为随质量浓度升高抑制作用增强,且处理间差异达到显著水平(P <0.05),并在0.10 g/mL处理中完全抑制白茅种子萌发,狗尾草发芽率较对照降低了78.33百分点。黄菊茎叶浸提液对白茅的鲜质量、干质量和苗高均表现为低质量浓度(≤0.02 g/mL)促进、高质量浓度(≥0.06 g/mL)抑制,在0.02 g/mL处理组中鲜质量、干质量和苗高分别高出对照78.23%(P <0.05)、9.55%和26.27%(P <0.05)。黄菊茎叶浸提液对狗尾草的干质量和鲜质量同样表现为"低促高抑",但临界点不同,其对狗尾草苗高的影响表现为浓度越高抑制作用越强,在0.10 g/mL处理组中低于对照78.78%。随黄菊茎叶浸提液质量浓度升高,白茅和狗尾草的根长受到强烈的抑制作用,在0.06 g/mL处理组显著低于对照96.43%和79.81%(P <0.05)。黄菊茎叶浸提液对2种杂草的综合化感效应均表现为抑制作用。【结论】黄菊能对白茅和狗尾草产生抑制作用,在油茶林下间作黄菊可降低除草成本,增加效益。

Allelopathic effects of Chrysanthemum morifolium on seed germination and seedling growth of two weed species in Camellia oleifera forest

【Objective】To explore allelopathic effects of Chrysanthemum morifolium on weeds,and to provide a reference for reducing weeding costs and enhancing benefits in Camellia oleifera forest.【Method】Imperata cylindrica and Setaria viridi were used as recipients.Seed germination was tested by using Petri dish filter paper method.Seeds were treated by using different mass concentrations of leaching solutions from C.morifolium stem-leaf and its rhizosphere soil.Seed germination indexes and seedling growth indexes were measured in different treatments.【Result】In C.morifolium rhizosphere soil leaching solution treatments,seed germination in I.cylindrica is promoted under condition of low mass concentration(≤0.02 g/mL)and inhibited under condition of high mass concentration(≥0.06 g/mL),but seed germination in S.viridi is inhibited under condition of each concentration.Rhizosphere soil leaching solution(0.02,0.06 and 0.10 g/mL)can promote fresh mass,dry mass,height and root length in I.cylindrica seedlings.As mass concentration of rhizosphere soil leaching solution increased,its promoting effects on fresh mass and height show a weaken tendency,and its promoting effects on dry mass and root length are increased.Dry mass and root length reach the maximum values in 0.1 g/mL treatments,which are significantly higher than CK by 29.94%and 53.74%,respectively(P<0.05).Rhizosphere soil leaching solution has the same effects on dry mass and root length in S.viridi seedlings as those in I.cylindrica,which are higher than CK by 47.67%(P<0.05)and 6.59%in 0.10 g/mL treatments.But its effects on fresh mass and height in S.viridi seedlings show promoting under condition of low mass concentration and inhibiting under condition of high mass concentration.In C.morifolium stem-leaf leaching solution treatments(0.02,0.06 and 0.10 g/mL),its inhibition effect on seed germination of both recipients is increased with increase of mass concentration,and differences between treatments are significant(P<0.05).In 0.10 g/mL treatments,seed germination of I.cylindrica is completely inhibited,and seed germination rate in S.viridi is lower than CK by 78.33 percent points.Effects of C.morifolium stem-leaf leaching solution on fresh mass and height in S.viridi seedlings show promoting under condition of low mass concentration(≤0.02 g/mL)and inhibiting under condition of high mass concentration(≥0.06 g/mL).In 0.02 g/mL treatments,fresh mass,dry mass,and height in I.cylindrica seedlings are higher than CK by 78.23%(P<0.05),9.55%,and 26.27%(P<0.05).C.morifolium stem-leaf leaching solution has the same effects on dry mass and root length in S.viridi seedlings as those in I.cylindrica,but critical points are different.Its inhibition effect on height in S.viridi seedlings is higher with increase of mass concentration,which is lower than CK by 78.78%in 0.10 g/mL treatments.Root lengths of both weed species are strongly inhibited with increase of mass concentration of C.morifolium stem-leaf leaching solution,and are significantly lower than CK by 96.43%and 79.81%(P<0.05)in 0.06 g/mL treatments.Comprehensive allelopathic effects of C.morifolium stem-leaf leaching solution on both weed species show inhibition effects.【Conclusion】C.morifolium can inhibit I.cylindrica and S.viridi,and intercropping C.morifolium in Camellia oleifera forest can reduce weeding costs and enhance benefits.