Published online September 2, 2022
Journal of Ecology and Environment (2022) 46:23
© The Ecological Society of Korea.
1Department of Biology Education, Seoul National University, Seoul 08826, Republic of Korea
2Center for Education Research, Seoul National University, Seoul 08826, Republic of Korea
Correspondence to:Jae Geun Kim
#These authors equally contributed to this work.
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
Background: Mixed breeding herb
Results: The number of flowers, including chamogamous and cleistogamous flowers, was highest (5.65/pot) under 60% light and fertilized condition and lowest (1.41/pot) under 100% light and not-fertilized condition. However, above ground vegetative growth was highest (2.89 g/pot) under 100% light and fertilized condition and lowest (2.38 g/pot) under 60% light and not-fertilized condition. Above ground biomass to belowground biomass ratio was highest (1.50) under 60% light and fertilized condition and lowest (1.26) under 100% light and fertilized condition.
Conclusions: This study showed that high light and nutrient are responsible for the vegetative growth , though the effect of fertilizer was reduced due to allocation and retainment of nutrients. In addition, the low light is necessary to make flowers, especially chasmogamous flowers.
Keywords: chasmogamous flower, cleistogamous flower, plasticity, shade
Climate change, especially global warming, makes trees to sprout early and forest canopy to close earlier (Nam and Kim 2020). These environmental changes could impact more significantly to
Although there are several previous studies about
In this study, we focused on independent and potentially interacting effects of two principal environmental factors for the growth of mountainous herbaceous plants, shade and soil fertility, to understand the ecological characteristics of
The effects of shade and fertilizer on the growth of
We counted the numbers of leaves (2017), chasmogamous (2017) and cleistogamous (2016–2017) flowers, and fruits (2016–2017) of each plant in the interval of 1 or 2 weeks. The chlorophyll content of the leaves was measured as a Soil Plant Analysis Development (SPAD) value using a portable chlorophyll meter (SPAD-502; Konica Minolta, Inc., Osaka, Japan) at 3th August and 5th November 2016 and 28th August 2017. Three leaves were randomly selected per pot and SPAD values were measured and averaged for each measurement. The SPAD sensor was placed on leaf mesophyll tissue only with the main vein avoided. In addition, leaf area and weight of three randomly chosen leaves were measured to estimate the reproductive strategy and leaf functioning under varying light and fertilizer conditions. We measured coverage of each pot in order to estimate the growth rate of the plant, as the coverage is related to not only the size and density of the plant but also the amount of light that can be intercepted by plants. In the case of coverage, images of each plant were captured and analyzed using ImageJ (National Institutes of Health, Bethesda, MD, USA). At the end of the experiment (31 August, 2017), the aboveground materials were cut off at ground level, and the soil was carefully removed from the belowground materials. After each of these above-ground (AG) and below-ground (BG) components were harvested and oven-dried at 70˚C for at least 48 hours, dry weights of AG and BG biomass of each plant were measured. AG/BG ratio was calculated by dividing the dry weights of AG into the dry weights of BG.
The data were statistically analyzed by two-way ANOVA using the statistical software environment R ver. 3.3.3, and multiple comparisons were performed using the Duncan test (
The average number of leaves was significantly highest under shade and fertilized condition (98.65/pot), and lowest under light and not-fertilized condition (63.76/pot) (Fig. 3A). Although the average leaf area of 3 leaves was higher under shade conditions than light conditions, it was not statistically significant difference (Fig. 3B). The average weight of three leaves was highest under light and not- fertilized condition (0.49 g), followed by shade and not-fertilized (0.46 g), shade and fertilized (0.43 g), and light and fertilized (0.34 g) (Fig. 3C). Although the average coverage was higher under shade conditions than light conditions, it was not statistically significant difference (Fig. 3D). Leaf chlorophyll content was higher under shade conditions than light conditions (Fig. 3E).
The average aboveground dry weight showed no significant difference under light and fertilizer treatments (
Both light and fertilizer caused significant differences in reproductive and morphological traits of
Furthermore, production of
On the contrary, vegetative growth, especially morphological traits of leaves, significantly responded to different light and soil fertility conditions (Kim and Kim 2022). The number of leaves were affected by both light and fertilizer, whereas coverage and weight of leaves showed significant difference only under different light and soil fertility conditions, respectively. The number of leaves and coverage increased under shade condition. This can be understood as the result of shade tolerance as the maximization of light capture and photosynthesis in low light intensity conditions (Cooper and Qualls 1967). Leaf chlorophyll content was higher under shade conditions than light conditions. Higher leaf chlorophyll contents under low light intensity condition were widely accepted in previous studies (Cooper and Qualls 1967; Guenni et al. 2018). Higher leaf chlorophyll contents enhance the light use efficiency and thus improve carbon gain leading to the increase in shade tolerance (Givnish 1988; Valladares and Niinemets 2008).
In the case of AG and BG dry weights, the belowground dry weight decreased under shade conditions, and the ratio of AG and BG dry weight under shade conditions was comparatively greater than under light conditions (Fig. 4). This may be attributed to that more biomass was allocated to aboveground for higher carbon assimilation through photosynthesis under low light intensity conditions (Selzer et al. 2013), which has also been observed in other herbaceous species (Martina and von Ende 2012; Park et al. 2019). Although biomass allocation was shifted under different light treatments, it was not statistically significant difference. This is consistent with previous studies that a significantly lower biomass was attained only when light availability was reduced to 10% of full-sunlight intensity (Ryser and Eek 2000; Semchenko et al. 2012).
In the case of AG and BG dry weights, fertilizer treatment has resulted in non-significant change in their biomass (Fig. 4). This may be the result of retainment in phosphorus nutrients to support future growth (Fitter and Setters 1988). Fertilizer experiment in three
Fertilizer application could increase the allocation to aboveground organs and reduces allocation to belowground organs due to cheaply obtained nutrients (Bloom et al. 1985). However, this fertilizing could also result in increased leaf turnover, where keeping old leaves could be inefficient (Chabot and Hicks 1982). This could have suppressed the effect of fertilizer application to increase in above ground allocation and higher AG/BG ratio.
On the other hand, there was no significant interaction between light and soil fertility conditions in their effects on reproductive and vegetative growth of
HP did Investigation, data curation, writing - original draft preparation. GS did Investigation, data curation, writing - original draft preparation. JGK did conceptualization, methodology, writing - review & editing.
This research was supported by Korea Environmental Industry & Technology Institute (KEITI) through ‘Wetland Ecosystem Value Evaluation and Carbon Absorption Value Promotion Technology Development Project, funded by Korea Ministry of Environment (MOE) (2022003640003) and by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (NRF-2021R1I1A2041895).
The datasets used and analyzed during the current study are available from the corresponding author on reasonable request.
The authors declare that they have no competing interests.