Study on Seedling Techniques ofArtocarpus nanchuanensis

Xiaomei TAN，Yiquan ZHOU，Angui DENG，Yanting LlU，Yong PENG，Xiaozhou ZHOU

1.Chongqing Academy of Forestry，Chongqing 400036，China；

2.Chongqing Academy of Chinese Materia Medica，Chongqing 400065，China；

3.Forest Farm in Northern Qijiang District，Chongqing City，Chongqing 401420，China

Study on Seedling Techniques ofArtocarpus nanchuanensis

Xiaomei TAN1*，Yiquan ZHOU2，Angui DENG3，Yanting LlU3，Yong PENG3，Xiaozhou ZHOU1

1.Chongqing Academy of Forestry，Chongqing 400036，China；

2.Chongqing Academy of Chinese Materia Medica，Chongqing 400065，China；

3.Forest Farm in Northern Qijiang District，Chongqing City，Chongqing 401420，China

［Objective］This study aimed to solve the problems of low seed germination rate and difficult bareroot seedling transplanting in artificial cultivation ofArtocarpus nanchuanensis，a native species in China. ［Method］Under different seed treatment and seedling style，the seed germination rate and seedling emergence rate of A.nanchuanensis were investigated. ［Result］In both sand bed and direct sowing yellow soil，the seed germination rate，seedling survival rate and seedling emergence rate in the treatment II were all higher than those in the treatments I and III.The average seed germination rate，seedling survival rate and seedling emergence rate in sand beds were 1.5%，16.27%and 13.95%，respectively higher than those in direct sowing yellow soil.The average seedling emergence rate in sand beds was 2.46%higher than that in containers.Among the 8 kinds of light matrix formulas，the growth of seedlings in the formula VIII was best.In the three treatment groups，the seedling emergence rates，seedling heights and ground diameters in the formula VIII were all significantly different from those in the other formulas.The seedling growth in the formula I and III ranked second，while the seedling emergence rate，seedling height and ground diameter in the formula VII were the poorest.［Conclusion］If conditions allow，the formulas I（meadow soil∶vermiculite∶yellow soil=5∶3∶2），III （meadow soil∶perlite∶yellow soil=5∶3∶2）and VIII （peat∶forest top soil=6∶4）should be promoted in seedling with light matrixes.

Artocarpus nanchuanensis；Seed treatment；Seedbed seedling；Container seedling；Direct sowing yellow soil

A rtocarpus nanchuanensis S.S. Chang，S.H.Tan et z.Yu（Moraceae:Artocarpus）is a kind of tall arbor with fast growth.Its height can be up to 25 m，and diameter at breast height can be up to 60 cm.A.nanchuanensis was first discovered in the territory ofNanchuan County，Chongqing City in 1982.Due to fine and hard texture，as well as difficult cracking and warping， A. nanchuanensis has become excellent material for furniture.In addition，A. nanchuanensis has beautiful tree type with great ornamental value，so it is also excellent shade and landscaping tree.In 2008，A.nanchuanensis was listed in the Urban Planning of Landscape Trees in Chongqing City due to its robust growth and beautiful type. Thus，A.nanchuanensis becomes one of the nine tree species for urban landscaping.However，A.nanchuanensis has rare germplasm resources and low bareroot seedling transplant ing survival rate.This explains why A.nanchuanensis has not been pro moted in a large scale.The fruits of A.nanchuanensis have high nutritional value，and their fresh flesh is rich in trace elements and vitamins essential for human body.In addition，the fruits of A.nanchuanensis can also be used as medicine［1］.

A.nanchuanensis is rarely distributed in China，so it has become one dying species.Currently，there are only 6 existing wild populations，in-cluding 80 fruiting mother trees.The annual seed yield of A.nanchuanensis is less than 50 kg.Due to destroyed living environment and weak regeneration capacity，the population of A. nanchuanensis drops sharply.At present，A.nanchuanensis population has been on the verge of extinction，and has become a very small population.Therefore，it is urgent to carry out rescue work to protect the breeding of A.nanchuanensis.Artificial propagation and cultivation and offsite protection are inevitable choices to expand the population and solve the endangered status of A.nanchuanensis. There have been rare reportson seedling of A.nanchuanensis in China up to now［1-3］.The results showed that A.nanchuanensis had low seedling emergence rate，and this severely restricted the rescue work for the protection of A.nanchuanensis.To solve the problems of low seed germination rate and difficult bareroot seedling transplanting in artificial cultivation of A.nanchuanensis，a native species in China，a series of detailed researches on seedling of A.nanchuanensis were conducted in recent years，thereby providing technical support for artificial large-scale cultivation and breeding of A.nanchuanensis.

Materials and Methods

Overview of test site

The test was conducted in the Ganlan MountainNurseryinGele MountainofShapingbaDistrict，Chongqing City （29°29′33″-29°44′58″N，106°14′40″-106°26′27″E）.The test site has a subtropical monsoon climate with altitude of 500 m，annual average temperature of 17.9℃，temperature in hottest month of 36-38.5℃，extremely high temperature of 44℃，extremely low temperature of-2.5℃，annual precipitation of 1 024.4 mm （the precipitation during June to September is 663.7 mm，accounting for more than 50%of the annual precipitation），annual evaporation of 1 024.16 mm，annual relative humidity of 79%，annual average fog period of 47.5 d and annual average sunshine rate of 27%.

Materials

The seeds of A.nanchuanensis were provided by the Forest Farm in Northern Qijiang District.In the nursing of container seedlings，the used matrixes included peat，rice husk，forest top soil and yellow soil.The peat was collected from Northeast China.The forest top soil referred to the surface humus under certain mason pine forest.The remaining materials were all locally sourced.The collected rich husk was fully moistened，and then mixed with urea（2 kg/m3）and calcium super phosphate （3 kg/m3）.The mixture was sealed with plastic film for more than 6 months.During the fermentation，the mixture was stirred 2-3 times.The composted rice husk was filled in container bags.

Methods

Seed storage and treatment

The purchased A.nanchuanensis seeds were preserved in sand with appropriate humidity.Before the seeding，the seeds were sieved to obtain full and large seeds.

Preparation of seedling beds，sand beds and containers

The seedbeds were deeply（25-30 cm）tilled in March，2014.During the tilling，adequate basal fertilizer（20 g compound fertilizer/m2）was applied. The seedbeds were in width of 1.0 m and height of 25-30 cm.The periphery of the seedbeds was built higher. Around the seedbeds，draining ditches were dug.The seedbeds were sprayed with 50% carbendazim（500×），and after 7 days，the sowing was conducted.Before the sowing，the seedbeds were completely irrigated.

The sandbeds were prepared on the ventilated and sunny sandy loam. The underlying layer of the sandbeds was paved with the mixture of ferrous sulfate powder and fine soil（1:20）. Subsequently，a layer（15-20 cm）of wet fine sand was paved.The prepared sandbeds were disinfected with 50%carbendazim （500×）and then mulched with film for 2-3 d.

The plastic nutrition bowls with specifications of 18 cm×16 cm were selected for the preparation of container bags，and there were seepage holes at the bottom and on the walls of the bowls.According to the designed formulas，the bowls were filled with matrixes.Subsequently，the matrixes in the bowls were disinfected thoroughly with 3% ferrous sulfate solution.

Test design

A total of three treatments were designed.In treatment I，the seeds were soaked in 50%carbendazim（1 000×）for 12 h.In treatment II，the sand-preserved seeds were soaked in 50%carbendazim （1 000×）for 12 h. Theywereplaced ongermination trays，and the germinated seeds with radiculas primarily exposed were selected for sowing.In treatment III，the sand-preserved seeds were sowed directly.The nursing was conducted in sandbeds，yellow soil and light matrixes，respectively［4-6］.

A total of 8 kinds of formulas were designed for the container seedling，including formula I（meadow soil:vermiculite:yellow soil=5:3:2），formula II（meadow soil:fungi bag:yellow soil=5: 3:2），formula III（meadow soil:perlite: yellow soil=5:3:2），formula IV（meadow soil:rice husk:yellow soil=5:3:2），formula V（meadow soil:rice husk:yellowsoil=5:4:1），formula VI（meadow soil:rice husk:yellow soil=4:4:2），formula VII（meadow soil:rice husk:yellow soil=3:4:3）and formula VIII（peat: forest top soil=6:4）［7-11］.The randomized complete block design was adopted，and there were four replicates for each treatment.There were total 20 container bags in each plot，and there were two seeds sowed in each container bag.During the container seedling，the matrixes should be always kept moist.The broad-spectrum fungicide was sprayed once every 10 days.Under the condition of high temperature in summer，the plots were shaded.

lndicator measurement and methods

The emergence time，germinated seed number，germination rate，emerged seedling number，seedling emergence rate，seedling heightand ground diameter were observed and recorded.

Data statistics and analysis

The variance analyses and multiple comparisons（LSD）were conducted using SPSS 13.0.

Results and Analysis

Seedling emergence rates in different seed treatment groups

The seeds were treated on March 6，2014，and they were sowedin sandbeds，yellow soil and containers，respectively.The results showed that the seed germination rate，seedling survival rate and seedling emergence rate of A.nanchuanensis were 82.17%，80.11%and 65.2%，respectively（Table 1）.

The seed germination rates，seedling survival rates and seedling emergence rates of A.nanchuanensis in sandbeds and yellow soil were measured.Due to conditional restriction，only the seedling emergence rate was measured in the container seedling.The results showed that under different seedling style，the seed germination rate and seedling emergence rate of A.nanchuanensis in seedbeds were higher than those in the other two seedling styles.The average seedling emergence rate in seedbeds was 73.33%，which was 14.83%and 5.36%higher than those in yellow soil and containers.The seedling emergence condition in the yellow soil was worst，which might be due to poorer poriness and waterholding capacity of yellow soil.

Under different seedling style，the germinated seed number，seed germination rate，seedling survival rate and seedling emergence rate in the treatment II were all higher than those in treatments I and III.In the seedbeds，the seed germination rate in the treatment II was 89.5%，and the seedling emergence rate was 78%.The emergence time of A.nanchuanensis seeds in the treatment II of the sandbed seedling style was 20-35 d shorter than those in the other treatment groups of the seedbed and yellow soil seedling styles.The seedling emergence condition of the sand-preserved A.nanchuanensis seeds which were directly sowed in yellow soil was worst. In the production，the transplanting survivalrate ofA.nanchuanensis bareroot seedlings is usually low due to their fleshy roots.Therefore，to improve the transplanting survival rate of A.nanchuanensis，container seedlings are required by mountain afforestation. This study found that the seedling emergence rate of A.nanchuanensis in light matrix containers was lower than that in sandbeds.However，after the germination promotion treatment，the seedling emergence rate of A.nanchuanensis was equivalent between the two seedling styles.Therefore，in the production，if conditions allow，the A.nanchuanensis seedlings can be transplanted into container bags after the germination promotion treatment；if conditions disallow，the A.nanchuanensis seeds can be first sowed in sandbeds， and their seedlings can be then transplanted into container bags.Thus，the survival rate of A.nanchuanensis seedlings in afforestation is ensured，and the operation costs in the production are reduced as well.

Table 1 Seedling emergence conditions ofA.nanchuanensisin different treatment groups

Seedling emergence rate and growth status in light matrix

The container seedling test was conducted in March，2014.The seedling emergence rates，seedling heights and ground diameters of A.nanchuanensis in different seed treatmentgroups were measured. The results of variance analyses and multiple comparisons were shown in Table 2.

As shown in Table 2，there were great differences in seedling emergence rate，seedling height and ground diameter among different seed treatment groups.Among the three seed treatment groups，the seedling emergence rate and seedling growth in the treatment II were higher than those in the othertwo treatment groups.The average seedling emergence rate of A.nanchuanensis in the treatment II was 75.55%，which was 8.21%and 14.53%higher than those in the othertwo treatment groups.The average seedling height of A.nanchuanensis in the treatment II was 2.06 and 4.44 cm higher than those in the othertwo treatment groups.The average ground diameter of A.nanchuanensis in the treatment II was 0.021 and 0.061 mm higher than those in the othertwo treatment groups.Among the 8 kinds of light matrix formulas，the seed germination rate and seedling growth were best in the formula VIII，followed by formulas I and III，while in the formula VII were worst.

The variance analysisshowed that there were significant differences in seedling emergence rate and seedling growth among different light matrix formulas.In the three treatment groups，the seedling emergence rate and seedling growth in the formula VIIIwere all better those in the other formulas.The seedling emergence rate and seedling height，instead of ground diameter，in the formula VII were all lower than those in the other formulas. There were no significant differences in seedling emergence rate，seedling height or ground diameter among formulas IV，V and VI，or between formulas I and III，but there were significant differences between formulas IV，V，VI and I，III.

Based on the analysis above，it could be concluded that treatment II was the best for seed treatment of container seedling，and formulas I，III and VIII were the best for the container seedling of A.nanchuanensis.

Conclusions and Discussion

The average seed germination rate，seeding survival rate and seedling emergence rate of A.nanchuanensis in seedbeds，yellow soil and container bags were 82.17%，80.11%and 65.92%，respectively.Among the three seedling styles，the seed germination rate （84.17%）and seedling emergence rate（73.33%）in sandbeds were the highest，while the seed germination rate and seedling survival rate in direct sowing yellow soil were the lowest.The survival rate of transplanted A.nanchuanensis bareroot seedlings is low due to their fleshy roots.Therefore，in the production，container seedling is required to improve the survival rate of A.nanchuanensis in afforestation.This study found that the seedling emergence rate of A.nanchuanensis in container bags was lower than that in sandbeds，but after the germination-promoted treatment，the seed germination rate was equivalent between the two seedling styles. Therefore，in the production，if conditionsallow，the A.nanchuanensis seedlings can be transplanted into container bags after the germination promotion treatment；if conditions disallow，the A.nanchuanensis seeds can be first sowed in sandbeds，and their seedlings can be then transplanted into container bags.Thus，the survival rate of A.nanchuanensis seedlings in afforestation is ensured，and the operation costs in the production are reduced as well.

After the seed soaking and germination-promoted treatment， the seed germination rate and seedling survival rate of A.nanchuanensis were 89.5%and 78%，respectively，which were higher than those in the soaking and direct sowing，and non-soaking and direct sowing treatment groups. The directly-sowed sand-preserved seeds of A.nanchuanensis showed the lowest germination rate.

In the containerseedling，the seedling emergence rate of A.nanchuanensis in the treatment II was 75.55%，which was 8.21%and 14.53% higher than those in the treatments I and III.In addition，the seedling height and ground diameter of A.nanchuanensis in the treatment II were also higher than those in the other two treatment groups.

The seedling emergence rate and growth of A.nanchuanensis were different among different light matrix formula.Among the 8 kinds of light matrix formulas，the growth of A.nanchuanensis seedlings was best in the formula VIII，followed by formulas I and III.The seedling emergence rate，seedling height and ground diameter of A.nanchuanensis in the formula VIII were all higher than those in the other formulas，while in the formula VII were the lowest.If production conditions allow，the light matrix formulas I（meadow soil∶vermiculite∶yellow soil= 5∶3∶2），III（meadow soil∶perlite∶yellow soil=5∶3∶2）and VIII（peat:forest top soil=6:4）should be adopted in container seedling of A.nanchuanensis.

Table 2 Seedling emergence and growth conditions of A.nanchuanensis in different light matrix formulas

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Responsible editor：Tingting XU

Responsible proofreader：Xiaoyan WU

南川木波罗育苗技术研究

谭小梅1*，周益权2，邓安桂3，刘燕庭3，彭勇3，周小舟1（1.重庆市林业科学研究院，重庆400036；2.重庆市中药研究院，重庆400065；3.重庆市綦江区北部林场，重庆401420）

［目的］解决我国特有物种南川木波罗人工栽培过程中种子发芽率低，裸根苗移栽困难的难题，为实现南川木波罗较大规模的人工繁育栽培提供技术支撑。［方法］试验通过采用不同的种子处理方式和不同的育苗方式研究了南川木波罗的种子发芽率和出苗率情况。［结果］不管在沙床还是直播黄壤，处理Ⅱ的种子的发芽率、成苗率和总出苗率均高于处理Ⅰ和处理Ⅲ，其比直播黄壤高出分别为1.5%、16.27%和13.95%，相比轻基质容器育苗的总出苗率高2.46%。8种轻基质配方育苗结果显示，配方8的苗木生长情况最好，其出苗率和苗高、地径生长均与其他配方差异显著，其次是配方1和3，配方7的出苗率和苗高、地径生长情况最差。［结论］建议生产条件允许情况下，采用泥炭+森林表土=6：4（8号处理）或草甸土+蛭石+黄心土=5：3：2（1号处理）、草甸土+珍珠岩+黄心土=5：3：2（3号处理）开展轻基质育苗。

南川木波罗；种子处理；沙床育苗；容器育苗；直播黄壤

重庆市2013年野生动植物保护及自然保护区建设项目"南川木波罗繁育关键技术研究"。

谭小梅（1980-），女，四川眉山人，博士，副高，从事林木遗传育种研究。*通讯作者，E-mail：txmzyq2006@126.com。

2015-11-01

Supported by Wildlife Conservation and Nature Reserve Construction Projects of Chongqing City in 2013.

*Corresponding author.E-mail:txmzyq2006@126.com

Received:November 1，2015 Accepted:December 8，2015

修回日期 2015-12-08