Seed and Fruiting Phenology Plasticity and Offspring Seed Germination Rate in Two Asteraceae Herbs Growing in Karst Soils with Varying Thickness and Water Availability

doi:10.5814/j.issn.1674-764x.2022.02.014

Abstract

Abstract:

Shallow soil with low water availability is the key limiting factor for plant growth and reproduction in vulnerable karst regions. Annual herbs are pioneers adapted to these areas; however, little is known about the responses of their seeds and infructescence, and the germination of their offspring to these limited water and soil resources. In this study, we investigated how the seed and fruiting phenology plasticity and offspring seed germination rates of two annual Asteraceae herbs (Xanthium sibiricum and Bidens pilosa) respond to the harsh karst soil environment, by assessing the seed number, seed biomass and offspring seed germination rate. X. sibiricum and B. pilosa were grown under three soil thicknesses and three water availability levels in a full two-way randomized block design. The key results were as follows: (1) The number and biomass of progenies (infructescence and seeds) of X. sibiricum decreased with the decline of soil thickness and/or water availability (P <0.05). The infructescence and seed biomass of B. pilosa increased with the decline of water availability. (2) Seed quantity and seed biomass of X. sibiricum showed no correlation after their parents experienced resource reductions. A significant positive relationship between seed number and seed biomass was observed in B. pilosa (P <0.05). (3) The offspring seed germination rate of X. sibiricum did not change with the decrease of soil thickness under three levels of water treatment. However, the offspring seed germination rate of B. pilosa decreased significantly with the decrease of soil thickness under the control water level (P<0.05). The results show that X. sibiricum tends to improve its competitiveness by ensuring the quantity and quality of offspring in order to adapt to the shallow karst soils and dry karst habitats. In contrast, B. pilosa adapts to the unfavorable karst habitats by a risk-sharing strategy. B. pilosa produces more and bigger seeds to in an attempt to expand its survival range and escape from the unfavorable living environment, but this results in a lower seed number and germination rate of its progeny under the karst soil resource reduction.

Key words: karst drought, shallow soil, seed number, parental environment, seed biomass

LIU Junting, LI Suhui, SONG Haiyan, LEI Ying, CHEN Jinyi, WANG Jiamin, GUO Xuman, LIU Jinchun. Seed and Fruiting Phenology Plasticity and Offspring Seed Germination Rate in Two Asteraceae Herbs Growing in Karst Soils with Varying Thickness and Water Availability[J]. Journal of Resources and Ecology, 2022, 13(2): 319-327.

Figures/Tables 6

Table 1 Water design during the test

Months	W_CK	W_M	W_L
Apr.-Jun.	130 ml (3 d)^-1	65 ml (3 d)^-1	43 ml (3 d)^-1
Jul.-Sept.	125 ml (3 d)^-1	63 ml (3 d)^-1	38 ml (3 d)^-1
Oct.-Dec.	56 ml (3 d)^-1	28 ml (3 d)^-1	19 ml (3 d)^-1

Table 2 Relative soil water content under different treatments

	Water application
The thickness of the soil	W_CK		W_M		W_L
The thickness of the soil	Soil moisture content (%)	Relative water content	Soil moisture content (%)	Relative water content	Soil moisture content (%)	Relative water content
S_CK	19.16±0.71Aa	48%FC	14.13±0.32Ba	36%FC	10.81±0.33Ca	27%FC
S_M	20.55±0.53Aa	51%FC	12.86±0.46Ba	32%FC	9.36±0.70Ca	24%FC
S_L	21.05±0.57Aa	52%FC	12.60±0.71Ba	32%FC	7.47±0.38Cb	19%FC

Fig. 1 Effects of different thicknesses of the soil and water availability on infructescence (and seed) number and biomass of X. sibiricum and B. pilosa (M±SE) Notes: WCK, WM and WL: high (no reduction in water), moderate (50% reduction in water) and low (70% reduction in water) water availability, respectively. SCK, SM and SL: deep (70 cm), moderate (40 cm) and shallow (10 cm) thickness of the soil, respectively. Different lowercase letters indicate significant differences between different thicknesses of the soil under the same water availability (P < 0.05). Different uppercase letters indicate significant differences between different water availability levels under the same thickness of the soil.

Table 3 Results of Two-way ANOVA on the infructescence and seed number and biomass of X. sibiricum and B. pilosa

Species	Treatment	F-value
Species	Treatment	Infructescence number	Seed number	Infructescence biomass	Seed biomass
X. sibiricum	Water	5.36^**	11.72^**	15.26^**	6.29^**
	Soil	58.43^**	78.79^**	85.97^**	118.18^**
	Water × Soil	3.18^*	5.11^**	3.26^*	2.95^*
B. pilosa	Water	7.55^**	4.56^*	4.83^*	4.97^*
	Soil	216.49^**	142.38^**	212.94^**	162.22^**
	Water × Soil	4.10^**	0.34ns	1.36ns	0.38ns

Fig. 2 The relationship between seed number and seed biomass of X. sibiricum (a) and B. pilosa (b) Note: r: Pearson’s correlation coefficient; α: Regression slope. WCK, WM and WL: high (no reduction in water), moderate (50% reduction in water) and low (70% reduction in water) water availability, respectively. SCK, SM and SL: deep (70 cm), moderate (40 cm) and shallow (10 cm) thickness of the soil, respectively; *, ** and *** indicate significant differences at P < 0.05, P < 0.01 and P < 0.001, respectively; ns: no significant difference at the 0.05 level.

Fig. 3 The effect of different thicknesses of soil and water availability levels on offspring seed germination rates of X. sibiricum and B. pilosa Note: WCK, WM and WL: high (no reduction in water), moderate (50% reduction in water) and low (70% reduction in water) water availability, respectively. SCK, SM and SL: deep (70 cm), moderate (40 cm) and shallow (10 cm) thickness of the soil, respectively. Different lowercase letters indicate significant differences between the different thicknesses of soil under the same water availability level (P < 0.05).

References 45

[1]	Bruno C, Roberta M C, Marco C, et al. 2003. Seed size, shape and persistence in soil: A test on Italian flora from Alps to Mediterranean coasts. Seed Science Research, 13(1): 75-85. DOI URL
[2]	Chen H S, Feng T, Li Z C, et al. 2018. Characteristics of soil erosion in the karst regions of Southwest China: Research advance and prospective. Journal of Soil and Water Conservation, 32(1): 10-16. (in Chinese)
[3]	Chen L R, Li Y Y. 2018. Responses of seed production and vigor in Caragana korshinskii to simulated precipitation variation. Journal of Northwest Forestry University, 33(6): 26-31. (in Chinese)
[4]	Coomes D A, Grubb P J. 2003. Colonization, tolerance, competition and seed-size variation within functional groups. Trends in Ecology & Evolution, 18(6): 263-291. DOI URL
[5]	Dilixiati H, Wu H Q, Maimaitijiang T, et al. 2014. Module biomass structure of two Xanthium species in different ecological environment habitats. Xinjiang Agricultural Sciences, 51(4): 708-713. (in Chinese)
[6]	Edwards B R, Burghardt L T, Zapata-Garcia M, et al. 2016. Maternal temperature effects on dormancy influence germination responses to water availability in Arabidopsis thaliana. Environmental and Experimental Botany, 126: 55-67. DOI URL
[7]	Ellers J, Stuefer J F. 2010. Frontiers in phenotypic plasticity research: New questions about mechanisms, induced responses and ecological impact. Evolutionary Ecology, 24(3): 523-526. DOI URL
[8]	Eric I, Ophélie R. 2001. Phenotypic plasticity for dispersal ability in the seed heteromorphic Crepis sancta (Asteraceae). Oikos, 93(1): 126-134. DOI URL
[9]	Galloway L F. 2005. Maternal effects provide phenotypic adaptation to local environmental conditions. New Phytologist, 166(1): 93-100. PMID
[10]	Greipsson S, Davy A J. 1995. Seed mass and germination behaviour in populations of the dune-building grass Leymus arenarius. Annals of Botany, 76(5): 493-501. DOI URL
[11]	He J Y, Zhang M J, Wang P, et al. 2011. Climate characteristics of the extreme drought events in Southwest China during recent 50 years. Acta Geographica Sinica, 66(9): 1179-1190. (in Chinese)
[12]	Jiang M, Lin Y, Chan T O, et al. 2020. Geologic factors leadingly drawing the macroecological pattern of rocky desertification in southwest China. Scientific Reports, 10(1): 465-474. DOI URL
[13]	Jiang Z C, Lian Y Q, Qin X Q. 2014. Rocky desertification in Southwest China: Impacts, causes, and restoration. Earth-Science Reviews, 132(3): 1-12. DOI URL
[14]	Kathleen D. 2009. Completing the cycle: Maternal effects as the missing link in plant life histories. Philosophical Transactions of the Royal Society B-Biological Sciences, 364(1520): 1059-1074. DOI URL
[15]	Lai L M, Tian Y, Wang Y J, et al. 2015. Distribution of three congeneric shrub species along an aridity gradient is related to seed germination and seedling emergence. AoB Plants, 7(1): 1-9.
[16]	Li S H, Liu J T, Li J M, et al. 2021. Reproductive strategies involving biomass allocation, reproductive phenology and seed production in two Asteraceae herbs growing in Karst soil varying in depth and water availability. Plant Ecology, 222(6): 737-747. DOI URL
[17]	Li S H, Zhao Y J, Wang L, et al. 2019. Growth and biomass allocation strategies of two different photosynthetic plants in rocky desertification habitats. Journal of Chongqing Normal University (Natural Science), 36(4): 106-111. (in Chinese)
[18]	Li X L, Wen H R, Wang X S, et al. 2018a. Phenotypic plasticity of Distylium chinense leaves in relation to soil environmental factors in heterogeneous habitats in the Three Gorges Reservoir Region. Acta Ecologica Sinica, 38(10): 3581-3591. (in Chinese)
[19]	Li Z, Liu J C, Zhao Y J, et al. 2017. Adaption of two grasses to soil thickness variation under different water treatments in a Karst region. Acta Ecologica Sinica, 37(5): 298-306. (in Chinese) DOI URL
[20]	Li Z, Zhao Y J, Song H Y, et al. 2018b. Effects of karst soil thickness heterogeneity on the leaf anatomical structure and photosynthetic traits of two grasses under different water treatments. Acta Ecologica Sinica, 38(2): 721-732. (in Chinese)
[21]	Lin H. 2018. The comparison study on reproductive ecology of Xanthium italicum Moretti and Xanthium sibiricum Patr.ex Widd. Diss., Shihezi, China: Shihezi University. (in Chinese)
[22]	Liu J Y, Du J C, Wang Z L, et al. 2018. Response of Medicago sativa L. and M. falcata L. to PEG drought stress in seed germination period. Chinese Journal of Grassland, 40(3): 27-34. (in Chinese)
[23]	Liu R H, Chen L, Tu H R, et al. 2020. Niche and interspecific association of main species in shrub layer of Cyclobalanopsis glauca community in karst hills of Guilin, southwest China. Acta Ecologica Sinica, 40(6): 2057-2071. (in Chinese)
[24]	Liu Y, El-Kassaby Y A. 2015. Timing of seed germination correlated with temperature-based environmental conditions during seed development in conifers. Seed Science Research, 25(1): 29-45. DOI URL
[25]	Luo W R, Hu G Z, Ganjurjav H, et al. 2021. Effects of simulated drought on plant phenology and productivity in an alpine meadow in Northern Tibet. Acta Prataculturae Sinica, 30(2): 82-92. (in Chinese)
[26]	Lv H C. 2015. Comprehend the life cycle of green flowering plants from the life of specific plants-teaching suggestions on “the life of green flowering plants”. Biology Teaching Journal, 40(11): 29-30. (in Chinese)
[27]	Mark W, Michelle L, Janice L, et al. 1996. Comparative ecology of seed size and dispersal [and discussion]. Philosophical Transactions of the Royal Society B-Biological Sciences, 351(1345): 1309-1318. DOI URL
[28]	Megumi K K, Inoue M, Ryoma K, et al. 2020. Seed size and weight of 129 tree species in Japan. Ecological Research, 35(5): 787-791. DOI URL
[29]	Ove E. 1999. Seed size variation and its effect on germination and seedling performance in the clonal herb Convallaria majalis. Acta Oecologica, 20(1): 61-66.
[30]	Pake C E, Venable D L. 1996. Seed banks in desert annuals: Implications for persistence and coexistence in variable environments. Ecology, 77(5): 1427-1435. DOI URL
[31]	Schmuths H, Bachmann K, Weber W E, et al. 2006. Effects of preconditioning and temperature during germination of 73 natural accessions of Arabidopsis thaliana. Annals of Botany, 97(4): 623-634. PMID
[32]	Sultan S E. 2000. Phenotypic plasticity for plant development, function and life history. Trends in Plant Science, 5(12): 537-542. PMID
[33]	Teng N J. 2006. Responses of Arabidopsis thaliana sexual reproduction patterns and leaf characteristics to changes in atmospheric CO₂ concentration. Diss., Beijing, China: Institute of Botany, The Chinese Academy of Sciences.
[34]	Wang K L, Zhang C H, Chen H S, et al. 2019. Karst landscapes of China: patterns, ecosystem processes and services. Landscape Ecology, 34(12): 2743-2763. DOI URL
[35]	Wu G L, Du G Z, Shang Z H. 2006. Contribution of seed size and its fate to vegetation renewal: A review. Chinese Journal of Applied Ecology, 17(10): 1969-1972. (in Chinese)
[36]	Xiao F, Sang J, Wang H M. 2020. Effects of climate change on typical grassland plant phenology in Ewenki, Inner Mongolia. Acta Ecologica Sinica, 40(8): 2784-2792. (in Chinese)
[37]	Yan D C, Wen A B, Bao Y H, et al. 2008. The distribution of ¹³⁷Cs in hilly upland soil on the Qianzhong Karst Plateau. Earth and Environment, 36(4): 342-347. (in Chinese)
[38]	Yan X H, Zeng J J, Zhou B, et al. 2019. Effects of drought stress on germination and seedling growth of heteromorphic achenes of Bidens alba. Chinese Journal of Ecology, 38(11): 3327-3334. (in Chinese)
[39]	Zhang J, Wang J M, Chen J Y, et al. 2019. Soil moisture determines horizontal and vertical root extension in the perennial grass Lolium perenne L. growing in Karst soil. Frontiers in Plant Science, 10: 629. DOI: 10.3389/FPLS.2019.00629. DOI PMID
[40]	Zhao R M, Zhang H, An L Z. 2019. Plant size influences abundance of floral visitors and biomass allocation for the cushion plant Thylacospermum caespitosum under an extreme alpine environment. Ecology and Evolution, 9(9): 5501-5511. DOI URL
[41]	Zhao Y J, Li Z, Song H Y, et al. 2017a. Effects of decline in soil depth and water resource on the photosynthesis of two grasses under mixed plan-tation in Karst regions. Pratacultural Science, 34(7): 1475-1486. (in Chinese)
[42]	Zhao Y J, Li Z, Zhang J, et al. 2017b. Do shallow soil, low water availability, or their combination increase the competition between grasses with different root systems in Karst soil? Environmental Science and Pollution Research, 24(11): 10640-10651. DOI URL
[43]	Zhou Y C, Wang S J, Lu H M. 2010. Spatial distribution of soils during the process of karst rocky desertification. Earth and Environment, 38(1): 1-7. (in Chinese)
[44]	Zhu Y. 2019. Effects of simulated rainfall pattern and sowing time on phenology and progeny seed germination characteristics of two annual plants. Diss., Changchun, China: Northeast Normal University.
[45]	Zhu Z H, Wang G. 2002. Study on the phenotypic plasticity and reproductive allocation of Avena sativa L. Journal of Lanzhou University (Natural Science), 38(1): 76-83. (in Chinese)