Enemy Tolerance of Eupatorium Plants

Yingzhi Chen

1,2 a

, Shunbo Yang

1,3 b

, Ruiqiang Guo

, Xingcheng Zhang

, Gengyun Pan

1,* e

and Ruifang Wang

1,* f

College of Agriculture and Forestry, Puer University, Puer, Yunnan, 665000, China

College of Agriculture, Shanxi Agricultural University, Jinzhong, Shanxi, 030000, China

College of Agriculture, Yunnan Agricultural University, Kunming, Yunnan, 650000, China

Keywords:

Natural Enemy, Invasive Plant, Tolerance.

Abstract: Alien plants can tolerance the feeding of natural enemy by compensatory growth. In this study, the growth

responses of invasive Eupatorium adenophorum and native E. fortune plants to simulated insect feeding

were analyzed. The results showed that the total biomass of E. adenophorum had no significant change after

simulated insect feeding. The results indicated that E. adenophorum rapidly increasanges, but the leaf

biomass ratio increased significantly; the total biomass of E. fortune decreased signifed the biomass of

photozygous organs to cope with the simulated leaf loss. As a result, the invasive plant E. adenophorum is

more tolerant than the native plant E. fortune.

1 INTRODUCTION

E. adenophorum is native to Mexico in North

America and Costa Rica in Latin America (Qiang

1998). Due to its strong reproductive capacity,

adaptability and fast spread rate, it has caused

serious harm to human beings, livestock and even

the ecological environment (Xiao 2009). At present,

the control methods of E. adenophorum mainly

include three types: artificial mechanical control,

chemical control and biological control (Wang

2004).Among biological control, Procecidochares

utilis Stone, Orthezia quadrua, Dorylus orientalis

were reported to damage E. adenophorum.

Procecidochares utilis StoneProcecidochares

utilis Stone is the specialist enemy of E.

adenophorum , belonging to Diptera (Diptera:

Muscidae), and has certain inhibitory effect on the

growth and reproduction of E. adenophorum (Gao

2019, Lei 2014). In 1945, the United States

introduced Brasilia sinensis from Mexico to Maui

Island of Hawaii and established the population, and

https://orcid.org/0000-0001-8095-4848

https://orcid.org/0000-0002-8832-1604

https://orcid.org/0000-0002-8116-209X

https://orcid.org/0000-0003-2765-4090

https://orcid.org/0000-0002-9461-5158

https://orcid.org/0000-0003-4715-6240

succeeded in studying its biological characteristics

and the feasibility of using it to control the

population of E. adenophorum sinensis (Ming

2017). In July 1984, the Institute of Ecology of the

Chinese Academy of Sciences sent experts to

Yadong and Nyalam counties of Tibet, which are on

the border with Bhutan, Sikkim and Nepal, and

found the P. utili , which was introduced to some

areas of Yunnan, and then gradually spread to the

southwest of Sichuan, Guizhou and Guangxi (Wang

2013). It was found through experiments that the

oviposition only on the tender tips of E.

adenophorum plants, while the hatched larvae

crawled to the base of leaves, penetrated the

meristems, and entered the stems at the upper part of

the shoots, constantly feeding on the young parts at

the growth points of E. adenophorum, thus impeding

the circulation function of the three major vegetative

organs of E. adenophorum (Xin 1990). People make

full use of this habit to inhibit the normal growth and

development of E. adenophorum, and eventually

lead to the wilt of P. utili by E. adenophorum due to

malnutrition, so as to achieve the purpose of

biological control. In the course of its development

over the next 30 years, it was found everywhere, but

its control ability was very limited and it could not

achieve the desired effect.On the one hand, E.

adenophorum has the unique biological

characteristics of high seed yield, fast dispersal

Chen, Y., Yang, S., Guo, R., Zhang, X., Pan, G. and Wang, R.

Enemy Tolerance of Eupatorium Plants.

DOI: 10.5220/0011281200003443

In Proceedings of the 4th International Conference on Biomedical Engineering and Bioinformatics (ICBEB 2022), pages 739-743

ISBN: 978-989-758-595-1

739

speed, strong ability to regenerate tillers, and

vegetative reproduction of plant organs such as roots

and stems. On the other hand, it is only an insect, so

it takes some time to fully display its biological

characteristics. It is impossible to reach the degree

that E. adenophorum will wither and die

immediately once it is parasitic.For these two

reasons, the diffusion rate of E. adenophorum was

much faster than the parasitic rate of P. utili, so the

expected control effect could not be achieved .

In addition to specialist enemy, the growth of

some native generalist enemies is also a threat for

E. adenophorum. In April 2007, Chinese researchers

discovered another insect feeding on E.

adenophorum, O. quadrua, on the way from

Yingjiang to Tongbiguan Nature Reserve in Yunnan

Province. At the time, the researchers observed

damage in the field: the E. adenophorum had been

severely damaged, the whole plant turned brown and

withered. This insect mainly concentrates on the

stem of E. adenophorum, and mostly concentrates

on the node of the stem to suck the plant juice (Xu

2011).

It was found that the D. orientalis, which would

bite the stems and roots of E. adenophorum, form

holes or eat them completely, and damage the

epidermis, cortex, phloem, root cambium and xylem

tissues of E. adenophorum, thus resulting in the

death of E. adenophorum due to the nutrient

exchange between the broken roots and buds (Yao

2008). D. orientalis have a certain selectivity in

foraging activities. They usually prefer food with

foul or aromatic odor, and the strong and unique

odor of E. adenophorum is the chemical signal that

attracts D. orientalis to forage (Chen 2012).

However, plants tend to resist insect feeding

through their own defense mechanisms, such as

tolerance.Plant tolerance is the ability of a plant to

prevent, reduce, or repair damage by compensatory

growth. For example, Ellison (1960) believed that

the compensatory effect of plants was that the

feeding of herbivores was beneficial to the growth of

plants (Ellson 1960).Belsky believed that the

compensatory effect of plants was a positive

response to plant injury, and defined compensatory

growth as "the increase of plant biomass and seed

yield due to foraging" (Belsky 1986). Therefore,

after the research and induction of many scholars,

the increased biomass or seed yield of plants under

stress was defined as the compensatory effect of

plants.

Although several insect have been found and

damaged on E. adenophorum, we don't know much

about how E. adenophorum responds to native

generalists. In this study,we investigated the biomass

allocation of invasive E. adenophorum and native E.

fortune under natural enemies feeding. The findings

of this study are expected to improve our

understanding of the compensatory growth of E.

adenophorum and native plant, and to evaluate the

role of native generalist enemies in the process of

alienplant invasion.

2 MATERIALS AND METHODS

2.1 Materials

2.1.1 Seed Collection

Seed collection was carried out one year before the

trial. Since the seeds of E. adenophorum and E.

fortune belong to achenes with small and light size,

and difficult to collect manually, in order to prevent

the early shedding of seeds and the mixing of other

unknown seeds, so as to obtain a large number of

healthy, complete seeds with high germination rate,

the method of isolated seed collection was adopted

in this experiment. Isolation method of seed in

flowering plants (E. adenophorum flowering in

November - the following April, E. fortune

flowering for 7 - November), selected out from the

need for seed plants grow strong, no plant diseases

and insect pests, variety of pure plant, and then

according to the shape of the flowers of the plant to

choose appropriate to the size of the yarn pockets of

bagged processing.

After the seeds of bagged plants mature and fall

off, the collected seeds should be stored in a

ventilated and cool place to dry in the shade, and

then stored in the envelope bag prepared in advance

to prevent the seeds from being dampened and

mildewed.

2.1.2 Seedlings

The whole seedling breeding process of this

experiment was carried out under the condition of

50% light intensity in the greenhouse. To raise

seedlings, the prepared humus soil (0-10 mm Danish

Pinclop trophic soil) and sandy soil were evenly

mixed in a 3:2 ratio to form a seedling substrate.

Then put the mixed seedling substrate into the

seedling tray (size: 40 cm * 40 cm), until it is only

about 1 cm away from the hole plate, stop adding

soil. Then, continue to fill 19 seedling plates in the

same way.The 20 seedlings were divided into 2

groups (E. adenophorum group andE. fortune

ICBEB 2022 - The International Conference on Biomedical Engineering and Bioinformatics

740

group), with 10 seedlings in each group, and

corresponding labels were made. Next, lay a piece of

kraft paper on the ground, remove the previously

collected seeds from the envelope bag, and gently

rub them with your hands so that the seeds are

removed from the other non-seed structures and fall

onto the kraft paper. After the separation of all the

seeds is completed, the separated seeds are evenly

dispersed into the seedlings tray of the different

groups, and the number of seeds in each seedling

tray is controlled at about 100. Finally, the substrate

from the sieve is gently sifted evenly into the tray so

that the seeds in each tray are thinly coated with the

substrate and cannot be blown away by the wind or

washed away by water. When all this is done, water

the two groups of seeds with a water bottle. After

that, water it regularly every two days.

2.1.3 Thinning

When the palnt had three or four leaf, in order to

avoid crowded seedlings, mutual shading, save soil

moisture and nutrient, and cultivate strong seedling

and guarantee the seedling size is consistent.Thus

thinning for plant and dish were required, finally

every dish reserved 50-70 seedlings.

2.1.4 Transplant

When the height of seedlings were 5 cm,

transplanting was started. First, prepare a new

nutrient bowl (model: 30 cm * 35 cm) and an

adequate substrate (a mixture of river sand and soil

in a 1:2 ratio). Then, the transplanting substrate was

placed upto two-thirds of the bowl, and the

nutritional bowls were arranged in a pattern of 10

units per row and 4 units per column, with a

flowerpot tray under the arranged nutritional bowls.

After that, seedlings were raised.

The two plants that transplanted to nutritional

bowls should be watered thoroughly one day in

advance. When seedlings are raised, the root system

of the uprooted plants should be intact and not

damaged. One third of the soil at the base of the

roots should be removed, and the rotten roots and

rotten roots should be removed. In the process of

transplanting, the seedlings are held by one hand,

and the roots are placed in the dug soil nest. The

roots of the seedlings can not be twisted, but should

be smoothed, and the spaces around them should be

filled and compacted with soil. Transplanting should

not be too deep, the root of the plant can be planted.

After planting, seedlings should be watered again to

ensure the survival of seedlings after transplantation.

Since then, watering were taken once every two

days.If the growth of seedlings were slowed, and or

did not survive, these seedlings should be timely

supplemented. After two weeks of adaptation to 36

% light, the transplanted seedlings began to grow

under full light conditions.

2.1.5 Fertilization Management

The growth rate of plant seedlings is accelerated

after transplanting, then the vigorous growth period

begins. At this time, the seedling plant nutrients

gradually accumulated, rapid thickening of rhizome,

leaf number gradually increased, the demand for

fertilizer and water increased significantly.

Therefore, in order to promote the growth of the

stem and leaves, to meet the growth needs of the

plant seedlings, in this period, the corresponding

fertilization management should be carried out.

Firstly, according to the dosage of 0.5 g fertilizer

(N, P, K available nutrient content ≥ 35%) per kg of

soil, thus 2 g fertilizer per bowl was weighed. Then

dig a hole 5-10 cm deep in each of the four

directions about 5 cm from the seedlings. Finally,

0.5 g fertilizer was applied to each hole and then

covered with soil to prevent the volatile of fertilizer

and reduce waste.

2.2 Methods

Twenty sample plants of E. adenophorum and E.

fortune were divided into two groups. One group

was treated as simulated insect feeding (MN), in

which all leaves (except the top 2-4 young leaves) of

a single plant were removed about 50% of the area

of the single leaf. Another control treatment (CK) to

eliminate natural enemies was to apply a compound

insecticide to the leaves of the plants. After the

treatment was completed, the whole plant was

covered with a gauze net bag of suitable size.

At the end of the experiment, 5 samples out of 10

single plant replicates were randomly harvested in

both treatments (MN and CK) of E. adenophorum.

After the roots, stems and leaves of the plants were

thoroughly rinsed and dried, each plant was divided

into three parts: root, stem and leaves, and the

weight of root, stem and leaves was weighed by an

electronic balance (accurate to 0.001g). Then put the

weighed roots, stems and leaves into three different

envelope bags, and mark the corresponding numbers

under different treatment methods on the envelope

bags. After completion, all the envelope bags were

put into an oven, which was first dried at 105 ℃ for

1 h, and then baked at 65 ℃ for 48 h until the

Enemy Tolerance of Eupatorium Plants

741

sample was constant weight. Finally, after standing

for 10 h, the samples in each envelope bag were

weighed again. E. fortune did the same thing.

Total biomass (total biomass = root weight +

stem weight + leaf weight), root biomass ratio

(RMR, root weight/plant total weight), stem biomass

ratio (SBR, supporting structure biomass/plant total

weight), leaf biomass ratio (LMR, leaf weight/plant

total weight), root/shoot ratio (R/C, underground

biomass/aboveground biomass), tolerance

(BMN-BCK)/BCK).

3 RESULTS AND ANALYSIS

3.1 Dry Biomass Allocation

The root biomass ratio and root-shoot ratio of E.

adenophorum in the control group were significantly

lower than those of the same native plant, E. fortune.

While the leaf biomass ratio was significantly higher

than that of E. fortune. The root biomass ratio and

root-shoot ratio of E. adenophorum in the simulated

insect feeding group were significantly lower than

those of the native plant, while the total dry weight

and leaf biomass ratio of E. adenophorum were

significantly higher than those of the native plant.

The results showed that the total dry weight of the

native plant E. fortune decreased significantly, while

the leaf biomass ratio of the invasive plant E.

adenophorum increased significantly after the

simulated insect feeding treatment.

Figure. 1. Dry biomass allocation

3.2 Fresh Biomass Allocation

Figure 2: Toal fresh weight of biomass (TFW).

Figure 3: Fresh biomass allocation.

The root biomass ratio and root-shoot ratio of E.

adenophorum in the control group were significantly

lower than those of the same native plant, E. fortune.

While the leaf biomass ratio was significantly higher

than that of E. fortune. The root biomass ratio and

root-shoot ratio of E. adenophorum in the simulated

insect feeding group were significantly lower than

those of the native plant, while the total fresh weight

and leaf biomass ratio of E. adenophorum were

significantly higher than those of the native plant.

The results showed that the total fresh weight of the

plant decreased significantly, while the leaf biomass

ratio of E. adenophorum increased significantly after

simulated insect feeding.

3.3 Tolerance

There were no significant differences in the changes

of fresh stem water content and root-shoot ratio

water content of E. adenophorum and E. fortune.

While the changes of total water content, fresh root

water content and fresh leaf water content of E.

adenophorum were significantly lower than those of

E. fortune, the tolerance of E. adenophorum was

significantly higher than that of E. fortune.

ICBEB 2022 - The International Conference on Biomedical Engineering and Bioinformatics

742

Figure 4: Tolerance in different plants.

4 DISCUSSION AND

CONCLUSION

The growth strategies in the biomass allocation

were different between E. adenophorum and E.

fortune under herbivory. More biomass of E.

adenophorum were allocated to leaf compared to E.

fortune, which can confer its higher carbon income

and tolerance for biomass accumulation than native

E. fortune. thus its total biomass was significantly

higher than E. fortune after herbivory. Therefore, the

biomass allocation pattern made a great contribution

to the tolerance and invasion ability of the invasive

plant E. adenophorum.

ACKNOWLEDGEMENTS

This work was supported by the National Natural

Science Foundation of China (31660170) and

Outstanding Young Teacher program

(2020GGJS006).

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