Effects of Substitute Media on Development of Potted Cyclamen percicum Mill.

Liu Qing-chao, Wang Kui-ling, Liu Qing-hua*, Pan Hui-tang, and Zhang Qi-xiang

1Qingdao Agricultural University, Qingdao 266109, Shandong, China

2Beijing Forestry University, Beijing 100083, China

Effects of Substitute Media on Development of Potted Cyclamen percicum Mill.

Liu Qing-chao1, Wang Kui-ling1, Liu Qing-hua1*, Pan Hui-tang2, and Zhang Qi-xiang2

1Qingdao Agricultural University, Qingdao 266109, Shandong, China

2Beijing Forestry University, Beijing 100083, China

Five kinds of agricultural castoffs, such as sawdust and powder of coconut coir, were used as growing media to substitute the peat moss for potted Cyclamen percicum. It showed that most of the substitute media could fit for the growth of the root system without disturbing the spatial development of the root. The root activities of the plants in substitute media were all higher or not significantly lower than that in the contrast peat moss (PM). The substitute media might not make adverse effects on the biosynthesis of chlorophyll of C. percicum leaves, and the nutrient components contained in the substitute media itself was none of the content of mineral elements in the leaves. The morphological indexes of C. percicum plants growing in the substitute media except in the powder of coconut coir (PCC) were all better than those in the contrast PM. The synthetically evaluation index of the plant showed that the sawdust, the powder of maize core, the powder of soybean stalk, the powder of peanut hull could take place the peat moss totally in C. percicum industrialization cultivation.

agricultural castoff, Cyclamen percicum, substitute media, morphology, synthetically evaluation

Introduction

With the gradual improvement of soilless culture, greater attention has been given to the studies on the growing media. The peat moss is greatly used as a kind of perfect growing media which possesses very good physical and chemical characteristics, stable structure, and favorable application (Li et al., 1997; Kang et al., 2005). China is a big consumer of peat moss, the consumption is more than four million tons (Meng, 2004, 2006; Qiao, 2004), and the average price is about 200-260 RMB • m-3. There are three types of peat swamps: raised swamps, intermediate swamps and low level swamps, and in China the natural resources are mostly composed of the latter two types, which are not very fit for the growing media. So the imported peat moss is often used for protecting horticulture, and of course it ulteriorly increases the product cost.

After 1970s, with all the governments and researchers attaching weight to the ecological environment, it has become to the front research which focused on the field of facility horticulture to develop and utilize new types of substitute growing medium which is abundantly available, low cost, pollutionfree and easy to mass-production (Poole et al., 2003). According to Gerald (1991), we should mainly use the organic castoff as the substitute of the traditional growing medium to achieve recycled and sustainable utilization of the natural resources. Some foreign scholars used the compost, the agricultural castoff, the municipal sludge as the growing media to takeplace the peat moss partially or totally and made great achievement. The domestic researcheres (Liang et al., 1998; Ding et al., 1994; Li et al., 2002, 2003, 2004; Long et al., 2004) used the Non Woven, the reed dust, the sugarcane dust etc. as the media to grow Lycopersicun esculentum Mill, Capsicum frutescens L., Citrullus vulgaris Schrad and Cucumis melo L. and selected optimal corresponding culture medium to reduce the using of the peat moss at certain extent.

China is abundant of the rough materials, such as agricultural castoff, which can be used as soilless culture medium. Thus, we can reduce the consumption of the peat moss, release the pressure of environment conservation and promote the sustainable development of the socialist economy. In this paper, the sawdust (SD), the powder of coconut coir (PCC), the powder of maize core (PMC), the powder of soybean stalk (PSS), and the powder of peanut hull (PPH) were used as research materials to analyze the feasibility of being used as growing media for the potted C. percicum.

Materials and Methods

Facilities, materials and environments

The experiments were made in Multi-Span Greenhouse in Qingdao Agricultural University. This greenhouse has perfect equipments of automatic temperature control and gas exchange, which can provide a relatively steady growing environment.

PCC was provided by Beijing Forestry University Forest Science Co., Ltd.; PPH was provided by Mr. Wu Zirong from Xinzheng City, Henan Province; PMC was provided by Mr. Hu Yingen from Weihai, Shandong Province; PSS was provided by Mr. Gao Kexian from Weifang, Shandong Province; SD (of Pinus koraiensis) came from Beijing MU-SEN-LIN Wood-working Factory.

SD and PCC were fermented for five months, PPH, PMC, and PSS were fermented for only four months. In order to keep the coherence fermentation treatment process, no fertilizer was added in. The peat moss (PM) from Shuangyashan City, Heilongjiang Province was used as the contrast.

C. percicum 'goldsmith' was used as model plant. When C. percicum seedling bearing 4-5 leaves, transplanted them into plastic pots which were 16 cm in diameter using the materials mentioned above as growing media. Kept one third of the height of bulbs above the surface of the growing media. There were 50 pots under each treatment and each pot with one plant. The fertilizer was supplied by the Hoagland nutrient solution and kept EC 2.0-2.5. The experiment was carried out for three times. The contents of mineral elements in PM and different substitute media were presented in Table 1.

Effects of different substitute media on root activity of potted C. percicum

The root activity of the potted C. percicum plant under different substitute media was tested by the method of 2, 3, 5-Triphenyl Tetrazolium Chloride (TTC) stain using the root tip as experimental material.

Table 1 Contents of mineral elements in PM and different substitute media

Effects of different substitute media on plant morphology of potted C. percicum

Ten plants were selected randomly under each treatment to determine the plant height (excluding the flower and the flower stalk), diameter of the plant crown, number of the mature leaf, the diameter of the bulb and mature leaf in the middle of their growth and initial flower stage separately.

Fifteen plants were selected randomly under each treatment to count the flower number every 10 days from October 19th, 2008 to December 19th, 2008.

Effects of different substitute media on biomass of potted C. percicum

Four plants were selected randomly under each treatment, the above ground fresh weight (AGFW), the fresh weight of the bulb (FWOB) and the under ground fresh weight (UGFW) were measured using the electronic balance (0.01 g). Afterwards, the plant was dried at 105℃, the dry biomass of corresponding parts of the plant also was measured, they were the above ground dry weight (AGDW), the dry weight of the bulb (DWOB) and the dry weight under ground (UGDW).

Effects of different substitute media on mineral elements and chlorophyll of potted C. percicum plant

In this experiment, the contents of mineral elements were all of full contents. The content of element nitrogen (N) was measured by kieldahl method; the content of element phosphorus (P) was measured by the method of High Resolution Continuum Source-Atomic Absorption Spectrometry; the content of elements potassium (K), calcium (Ca), magnesium (Mg), ferrum (Fe), zinc (Zn), cuprum (Cu) were tested by Shimadzu AA-6800 atomic absorption spectrophotometer.

The content of chlorophyll of the leaf was tested by Ultraviolet Visible pectrometer after being extracted by the mixed liquor of ethanol and acetone.

Effects of different substitute media on SPAD index of potted C. percicum plant's leaf

Ten plants were selected randomly under each treatment, and five mature leaves from different directions of each plant were chosen to be tested SPAD index by the portable SPAD-502 chlorophyll determinator.

Effects of substitute media on growth of potted C. percicum plant after blossoming without fertilization

On October 21st, 10 pots of plants were chosen at random from each treatment and placed in an empty room which without artificial temperature and humidity control. On October 22nd, the last time of Hoagland nutrients solution was provided to the plants and then just water provided every three days. And from October 22nd, SPAD index of the leaf under different treatments were tested every 15 days. Two months later, the leave number, crown width and biomass were surveyed and a contrast was made to the data of October 21st.

Synthetical evaluation on growth index of C. persicum in different media

There were often in contradiction and even selfcontradictory of the single growth indexes when they were used to evaluate the development of the plant. So synthetical evaluations were used to investigate objectively and thoroughly the growth reaction of C. persicum plant in different substitute media. The following formula was used to account the subordinate function values. In the formula, M meant the quantitative value of the certain indicator in certain medium. Mmaxand Mminrepresented as the maximum and minimum value of the certain indicator. The average of the subordinate function values was considered the comprehensive index of the plant. The bigger the index, the better the plant developed.

Results

Effects of different substitute media on root activity of potted C. percicum plant

Data from Table 2 revealed that the root activity of the potted C. percicum in PCC was the lowest one, which was 42.8 μg • g-1FW • h-1, significantly lower than that in PMC, PSS and PPH, but there was no significant difference to that in PM and SD. The root activities of the plants in PM and SD were significantly lower than those in PSS and PPH, but the data also indicated that root activities of the plants in substitute media were all significantly higher or not significantly lower than those in the contrast PM.

Table 2 Effect of different media on root activity of C. persicum (μg • g-1FW • h-1)

Effects of different substitute media on plant morphology of potted C. percicum

It showed that at middle growth stage of the experiment, there was no significant difference of the plant heights between different substitute media and the contrast PM (Fig. 1). While, as to the crown diameter, C. percicum plant in PCC was 16.1 cm, significantly lower than that in the contrast PM and other substitute media. The crown diameter of the plant in SD was 22.6 cm, which was the biggest one and significantly higher than that in PM and other substitute media. The crown diameter of the plants in PPH, PMC and PSS was higher than that in the contrast PM, but there was no significant difference (Fig. 2).

Fig. 1 Height of C. persicum in different media

Fig. 2 Crown diameter of C. persicum in different media

The leaf numbers of C. percicum plant in substitute media were all significantly higher than that in the contrast PM, but the leaf number of the plants in PCC significantly lower than that in other substitute media which just had 18.6 leaves per plant (Fig. 3). As to the diameter of leaves, the plant in PCC was 8.8 cm, significantly higher than that in the contrast PM and SD, but there was no significant difference to other substitute media.

At the initial flower stage, the growth indexes of the plants in PCC were lower than that in other media. Among them, the plant heights and the crown diameters were significantly lower than those in the contrast PM and other substitute media, while the leaf number and leaf diameter of the plants in PCC were of no significant differences to the contrastPM, but significantly lower than those in other substitute media. The growth indexes of the plants in other substitute media were all significantly or not significantly higher than those in the contrast PM.

Fig. 3 Leaf numbers of C. persicum in different media

Fig. 4 Leaf diameter of C. persicum in different media

According to international general standards, the potted C. persicum might not be on sale unless it has more than seven flowers. In the cultivation process of C. persicum, it bloomed successively from early October. Up to November 19th, it achieved more than seven flowers per plant, and arrived to the selling standard in the media of SD, PMC and PSS. The plants in PPH and the contrast PM arrived to the selling standard at November 29th. But the plants in PCC still had few flowers. By the time of December 9th, the plants in all the growing media including the contrast PM and the substitute media arrived the selling standard, and in which, the flower numbers of the plants in SD, PMC and PSS were higher than those in the contrast PM, PCC and PPH. The flower numbers of the plants in PCC were significantly lower than those in the contrast PM, and there was no significant difference of that between PPH and the contrast PM.

Fig. 5 Flower numbers of C. persicum in different media

Effects of different substitute media on biomass of potted C. percicum

At the initial flower stage, the leaf of C. percicum in PCC was in abnormal state, which was rumpled and large. The data indicated that the total fresh biomass of the plants in PCC was 108.1 g, significantly lower than that in the contrast PM and other substitute media. The total fresh biomasses of the plants in media SD, PMC, PSS and PPH were of no significant differences between each other, but all significantly higher than those in the contrast PM. Among them, the fresh biomass of the plants in the media SD was the most highly one, which was 234.3 g (Table 3).

The dry biomass of different parts of C. percicum plants in different growing media was of significant difference. Among them, AGDW and DWOB of the plants in PCC, which were 7.56 g and 0.56 g, significantly lower than those in the contrast PM and other substitute media, while UGDW was significantly higher than that in contrast PM, but significantly lower than that in other substitute media. AGDW and UGDW of the plants in SD reached to 15.30 g and 2.72 g, which were the most highly ones. DWOB of the plants in PPH was 1.10 g, higher than that in the contrast PM and other substitute media (Table 3).

From Table 4, we knew that there were no significant differences of the contents of the elements K,Mn and Cu among the plants which were in different growing media. Comparatively speaking, the contents of the elements Ca, Mg, Zn, and Fe of C. persicum plant in PCC were relatively low, and were significantly different to the plants in PM and other substitute media. The correlativity analyses between the elements contents of C. persicum leaves and the unused growing media showed that the relativities of N and Mg were 0.4569 and 0.4688. But to other elements, the relativities were very low and even negative correlations were found. So according to the author, there was no noticeable effect of the growing medium itself on the element contents of the plants. The determinant might be the nutrient solution.

At the middle growth stage, the chlorophyll content of the plants in PCC was significantly lower than that in PM, SD and PPH, SPAD index of the plants in PCC was significantly lower than that in SD, PMC and PPH, but was not significantly different to the plants growing in the contrast PM. The chlorophyll content of the plant in SD was 1.086 mg • g-1FW which was the highest one, according to SPAD indexes, the highest one was the plant in PPH and SD, which were 51.2 and 50.2. At the initial flower stage, there were no significant differences of the chlorophyll content of C. persicum plants between other growing media. There was no significant difference of SPAD index of the plants in PCC and PSS, but was both significantly lower than that in the contrast PM. SPAD indexes of the plants in the substitute media of SD, PMC, PPH and the contrast PM were of no significant difference (Table 5).

Table 3 Biomass of C. percicum in different growing media

Table 4 Contents of mineral elements of C. persicum in different media

Effects of substitute media on growth of potted C. percicum plant after blossoming without fertilization

The results from Table 6 indicated that after two months of no fertilization, the above ground biomass (AGFW) of all the plants in the contrast PM and substitute media obviously increased by about 10%. AGFW of the plants in SD increased by 9.9%, which was the lowest one, significantly lower than that inthe contrast PM, but that not proved that SD was disadvantageous to the increasing of AGFW of the potted C. percicum plant without fertilization, for AGFW of the plants in SD was almost two times of that in the contrast PM at the time of beginning to stop fertilization. Although AGFW of the plants in SD increased a lesser extent than that in the contrast PM, the absolute increment of the plants was still higher than that in PM. The rises of crown diameter and leaf number of the plants in PCC were significantly lower than those in the contrast PM, and there were no significant differences of the same growth indexes among other substitute media and other substitute media between PM (Figs. 6-8).

Table 5 SPAD index and Chlorophyll content of C. persicum

Fig. 6 C. persicum in middle period of growth in different media

Fig. 7 C. persicum in flowering period in different media

Fig. 8 C. persicum root system in different media

In the long period of no fertilization, SPAD indexes of the plants in all the substitute media except PCC were higher or not significantly lower than those in PM. At the time of 60 days of no fertilization, SPAD indexes of the plants in PM and all the substitute media except PCC were of no significant differences. And with the increasing of the days of no fertilization, SPAD indexes of the plants in all the growing media were improved at different degrees. That was probably the result of experimental error, because there was 60 days of interval between the first and the last time of measurements. But the experimental results at least indicated that compared with the contrast PM, the substitute media could not make further bad effects on the growth of C. persicum plants in the long period of no fertilization. Furthermore, a lot of nutrients had been stored up in the inflated bulbs, which could provide enough nutritions for the development of the plants (Table 7) .

Synthetical evaluation on growth index of C. persicum in different media

There are so many evaluation indexes to indicate the state of plant growing, but the single index is unilateral to illustrate the comprehensive character of the plant. So we used comprehensive index to estimate the plants. It showed that comprehensive indexes of the plants in SD, PMC, PSS, and PPH were 0.882, 0.832, 0.762 and 0.742, which were higher than those in the contrast PM. While comprehensive index of the plants in PCC was 0.04, lower than those in PM. This suggested that PCC was not a very good cultivating medium for C. persicum. Those four kinds of substitutes could be used to take place of the peat moss totally as soilless growing media. As to PCC, it should be first adjusted appropriately before using (Table 8) .

Table 7 SPAD indexes of C. persicum leaves in different media without fertilization

Table 8 Synthetical evaluation on growth index of C. persicum in different media

Discussion

The root is the vegetative organ of the plant underground, and it's also an active organ specialized for sucking and compounding nourishment. Together with the organ of aboveground, they make up a production system. The physical and chemical characteristics of the growing media greatly affect the developing of the root system, and then indirectly affect the morphogenesis of the aboveground. There is a physical contact between the root system and the growing medium, the medium of superior quality can afford a favorable root rhizosphere and steady supplying of the water and nutrients. From the cultivating experiment, we knew that in the growth process of C. persicum, most of the production of photosynthesis were transported to the above ground, so the biomass of the leaves of the plant took 80% biomass. Under the same condition, all the substitute media except PCC, could provide enough nutritive material and perfect environment for C. persicum plant. At the middle growth stage, C. persicum plant in PCC had a poor development. At the flowering period, the plant height, crown diameter, leaf number, and leaf diameter of the plant in PCC were all lower than those in other media, and made a poor stuff. The synthetically evaluation indexes of the plants in all the substitute media except PCC were higher than those in the contrast PM.

In the middle of October, the plants in all the treatments came into blossom in succession. By November 19, the plants in SD, PMC and PSS reached marketable size (possess seven flowers), which were about 10 days in advance than that in PM. By December 9, the plants in all the treatments achieved listing standard. Of the blooming situation, the plants in all the substitute media except in PCC were better than those in the contrast PM.

The chlorophyll content is an important indicator to represent the plant growth, and also can provide reliable reference to monitor the nitrogen level of the plants and to quantitatively fertilization. The environmental factors, such as mineral element, illumination, temperature and even air humidity, have great influence on the biosynthesis of chlorophyll. This research showed that the Hoagland nutrient solution could provide stable and balanced source of nutrition for C. persicum plant, and the substitute media could not make adverse effects to the biosynthesis of chlorophyll of the plants compared to the contrast PM.

C. persicum plant is sensitive to nutrient deficiency or nutrient excess, the former researches have indicated that the total fertilization concentration should be about 2 g • L-1(Tang et al., 2006; Mao et al., 2010). After two months of no fertilization, the plant height, crown diameter, and leaf number of the plants in all media have increased at different levels, but it increased smaller in PCC, and that proved PCC was not a good growing medium for C. persicumplant. The growth indexes of C. persicum plants in other substitute media were all no significant or significantly higher than those in the contrast PM. It had accumulated a lot of nutritions in C. persicum bulb by the time of the initial flower stage, compared with the contrast PM, the substitute media will not lead to nutrient deficiency in the growth process.

Conclusions

Based on the above data analyses, it is suggested that most plant fibrous materials could be used as substitute media to take place of PM totally or partially in cultivation for C. persicum and the growth potentials were generally better than those in PM. But the substitute media had lower performance of preserving moisture and fertility, under normal cultivating conditions, the plants developed well, but in order to keep the plants in good conditions, the substitute media depended more on extraneous nutrients from the nutrient solution than PM.

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S682.2+62

A

1006-8104(2014)-02-0028-10

Received 8 November 2013

Liu Qing-chao (1972-), male, Ph. D, associate professor, engaged in the research of garden plant cultivation. E-mail: liuqingchao7205@126.com

* Corresponding author. Liu Qing-hua, Ph. D, professor, engaged in the research of garden plant cultivation. E-mail: lqh6205@163.com