State Key Laboratory of Earth Surface Processes and Resource Ecology, College of Resources Science and Technology, BeijingNormal University, Beijing 100875, China
In order to explore the effects of grazing frequency on functional traits and to test whether Stipa gandis has compensatory photosynthesis during the frequent grazing period, we investigated morphological traits, biomass allocation, photosynthetic traits, and chlorophyll fluorescence parameters of the species in Inner Mongolia, China. The grazing frequency treatments included fencing (T0), grazing in May and July (T1, i.e., two months per year) and grazing from May to September (T2, i.e., continuous five months per year). Results indicate that T1 and T2 treatments did not affect individual biomass, but T2 treatment negatively affected individual size, i.e., plant height, stem length, and leaf length. Physiological traits of S. grandis were significantly affected by grazing, year, and their interaction. In July 2014 (i.e., dry environment and low relative humidity), the photosynthetic rate, transpiration rate and water use efficiency were highest under T2 treatment, which was caused by the increase in stomatal conductance. However, in July 2015 (i.e., wet environment and high relative humidity), the photosynthetic rate and water use efficiency were higher under T1 and T2 treatments, which were caused by the increase in actual quantum efficiency and stomatal conductance. Our results implied that under frequent grazing treatment, S. grandis had small height and efficient compensatory photosynthesis, which promoted its resistance to severe grazing.
Akiyama T, Kawamura K.2007. Grassland degradation in China: methods of monitoring, management and restoration. Grassland Science, 53(1): 1-17.
[2]
Aldea M, Hamilton J G, Resti J P, et al.2005. Indirect effects of insect herbivory on leaf gas exchange in soybean. Plant, Cell and Environment, 28(3): 402-411.
[3]
Adler P B, Milchunas D G, Lauenroth W K, et al.2004. Functional traits of graminoids in semi-arid steppes: a test of grazing histories. Journal of Applied Ecology, 41(4): 653-663.
[4]
Anderson T M, Dong Y, McNaughton S J.2006. Nutrient acquisition and physiological responses of dominant Serengeti grasses to variation in soil texture and grazing. Journal of Ecology, 94(6): 1164-1175.
[5]
Anderson T M, Kumordzi B B, Fokkema W, et al.2013. Distinct physiological responses underlie defoliation tolerance in African lawn and bunch grasses. International Journal of Plant Sciences, 174(5): 769-778.
[6]
Belsky A J.1986. Does herbivory benefit plants? A review of the evidence. The American Naturalist, 127(6): 870-892.
[7]
Cai Z Q, Qi X, Cao Q F.2004. Response of stomatal characteristics and its plasticity to different light intensities in leaves of seven tropical woody seedlings. Chinese Journal of Applied Ecology, 15(2): 201-204. (in Chinese)
[8]
Chen S P, Bai Y F, Lin G H, et al.2005. Effects of grazing on photosynthetic characteristics of major steppe species in the Xilin River Basin, Inner Mongolia, China. Photosynthetica, 43(4): 559-565.
[9]
Chen W J, Dong T, Gu C, et al.2015. Effect of different grazing intensities on root characteristics of Stipa grandis. Chinese Journal of Grassland, 37(4): 86-91. (in Chinese)
[10]
Christiansen S, Svejcar T.1988. Grazing effects on shoot and root dynamics and above- and below-ground non-structural carbohydrate in Caucasian bluestem. Grass Forage Science, 43(2): 111-119.
[11]
Copolovici L, Kännaste A, Remmel T, et al.2014. Volatile organic compound emissions from Alnus glutinosa under interacting drought and herbivory stresses. Environmental and Experimental Botany, 100: 55-63.
[12]
Deng Y, Liu X N, Xin X P, et al.2012. Diurnal dynamics of photosynthetic characteristics of Leymus chinensis under different grazing intensities taking the Hulunber meadow steppe as an example. Acta Prataculturae Sinica, 21(3): 308-313. (in Chinese)
[13]
Detling J K, Dyer M I, Winn D T.1979. Net photosynthesis, root respiration, and regrowth of Bouteloua gracilis following simulated grazing. Oecologia, 41(2): 127-134.
[14]
Díaz S, Cabido M.2001. Vive la différence: plant functional diversity matters to ecosystem processes. Trends in Ecology & Evolution, 16(11): 646-655.
[15]
Díaz S, Lavorel S, McIntyre S U E, et al.2007. Plant trait responses to grazing-a global synthesis. Global Change Biology, 13(2): 313-341.
[16]
Dorrough J, Ash J, McIntyre S.2004. Plant responses to livestock grazing frequency in an Australian temperate grassland. Ecography, 27(6): 798-810.
[17]
Fahnestock J T, Detling J K.2000. Morphological and physiological responses of perennial grasses to long-term grazing in the Pryor Mountains, Montana. The American Midland Naturalist, 143(2): 312-320.
[18]
Farquhar G D, Sharkey T D.1982. Stomatal conductance and photosynthesis. Annual Review of Plant Physiology, 33(1): 317-345.
[19]
Ferraro D O, Oesterheld M.2002. Effect of defoliation on grass growth. A quantitative review. Oikos, 98(1): 125-133.
[20]
Gassmann A J.2004. Effect of photosynthetic efficiency and water availability on tolerance of leaf removal in Amaranthus hybridus. Journal of Ecology, 92(5): 882-892.
[21]
Gregoriou K, Pontikis K, Vemmos S.2007. Effects of reduced irradiance on leaf morphology, photosynthetic capacity, and fruit yield in olive (Olea europaea L.). Photosynthetica, 45(2): 172-181.
[22]
Harrison M T, Kelman W M, Moore A D, et al.2010. Grazing winter wheat relieves plant water stress and transiently enhances photosynthesis. Functional Plant Biology, 37(8): 726-736.
[23]
Hodgkinson K.1974. Influence of partial defoliation on photosynthesis, photorespiration and transpiration by lucerne leaves of different ages. Australian Journal of Plant Physiology, 1(4): 561-578.
[24]
Hou F J.2001. Effect of grazing on photosynthesis and respiration of herbage and its absorption and transporation of nitrogen and carbon. Chinese Journal of Applied Ecology, 12(6): 938-942. (in Chinese)
[25]
Hu J, Hou X Y, Sa R L, et al.2016. Regulatory effects of Stip grandis on above-ground biomass of plant community in grazing ecosystem. Acta Agrestia Sinica, 24(1): 1-11. (in Chinese)
[26]
Lavorel S, Díaz S, Cornelissen J H C, et al. 2007. Plant functional types: are we getting any closer to the holy grail? In: Canadell J G, Pataki D E, Pitelka L F. Terrestrial Ecosystems in a Changing World. Berlin Heidelberg: Springer-Verlag, 149-164.
[27]
Li X L, Wu Z N, Liu Z Y, et al.2015. Contrasting effects of long-term grazing and clipping on plant morphological plasticity: evidence from a rhizomatous grass. PLoS ONE, 10(10): e0141055.
[28]
Louault F, Pillar V D, Aufrère J, et al.2005. Plant traits and functional types in response to reduced disturbance in a semi-natural grassland. Journal of Vegetation Science, 16(2): 151-160.
[29]
Lu C M, Zhang J H.1999. Effects of water stress on photosystem II photochemistry and its thermostability in wheat plants. Journal of Experimental Botany, 50(336): 1199-1206.
[30]
Macedo T B, Peterson R K D, Dausz C L, et al.2007. Photosynthetic responses of wheat, Triticum aestivum L., to defoliation patterns on individual leaves. Environmental Entomology, 36(3): 602-608.
[31]
Maschinski J, Whitham T G.1989. The continuum of plant responses to herbivory: the influence of plant association, nutrient availability, and timing. The American Naturalist, 134(1): 1-19.
[32]
Maxwell K, Johnson G N.2000. Chlorophyll fluorescence-a practical guide. Journal of Experimental Botany, 51(345): 659-668.
[33]
McNaughton S J.1979. Grazing as an optimization process: grass-ungulate relationships in the Serengeti. The American Naturalist, 113(5): 691-703.
[34]
Morrison K D, Reekie E G.1995. Pattern of defoliation and its effect on photosynthetic capacity in Oenothera biennis. Journal of Ecology, 83(5): 759-767.
[35]
Murchie EH, Lawson T.2013. Chlorophyll fluorescence analysis: a guide to good practice and understanding some new applications. Journal of Experimental Botany, 64(13): 3983-3998.
[36]
Nabity P D, Zavala J A, DeLucia E H.2008. Indirect suppression of photosynthesis on individual leaves by arthropod herbivory. Annals of Botany, 103(4): 655-663.
[37]
N'Guessan M, Hartnett D C.2011. Differential responses to defoliation frequency in little bluestem (Schizachyrium scoparium) in tallgrass prairie: implications for herbivory tolerance and avoidance. Plant Ecology, 212(8): 1275-1285.
[38]
Painter E L, Detling J K.1981. Effects of defoliation on net photosynthesis and regrowth of western wheatgrass. Journal of Range Management, 34(1): 68-71.
[39]
Peng Y, Jiang G M, Liu X H, et al.2007. Photosynthesis, transpiration and water use efficiency of four plant species with grazing intensities in Hunshandak Sandland, China. Journal of Arid Environment, 70(2): 304-315.
[40]
Redondo-Gómez S, Mancilla-Leytón J M, Mateos-Naranjo E, et al.2010. Differential photosynthetic performance of three Mediterranean shrubs under grazing by domestic goats. Photosynthetica, 48(3): 348-354.
[41]
Ruizr N, Ward D, Saltz D.2008. Leaf compensatory growth as a tolerance strategy to resist herbivory in Pancratium sickenbergeri. Plant Ecology, 198(1): 19-26.
[42]
Rusch G M, Skarpe C, Halley D J.2009. Plant traits link hypothesis about resource-use and response to herbivory. Basic and Applied Ecology, 10(5): 466-474.
[43]
Schiborra A, Gierus M, Wan H W, et al.2009. Short-term responses of a Stipa grandis/Leymus chinensis community to frequent defoliation in the semi-arid grasslands of Inner Mongolia, China. Agriculture Ecosystems & Environment, 132(1): 82-90.
[44]
Shipley B.2002. Trade-offs between net assimilation rate and specific leaf area in determining relative growth rate: relationship with daily irradiance. Functional Ecology, 16(5): 682-689.
[45]
Shipley B.2006. Net assimilation rate, specific leaf area and leaf mass ratio: which is most closely correlated with relative growth rate? A meta-analysis. Functional Ecology, 20(4): 565-574.
[46]
Van Staalduinen M A, Anten N P R.2005. Differences in the compensatory growth of two co-occurring grass species in relation to water availability. Oecologia, 146(2): 190-199.
[47]
Vesk P A, Leishman M R, Westoby M.2004. Simple traits do not predict grazing response in Australian dry shrublands and woodlands. Journal of Applied Ecology, 41(1): 22-31.
[48]
Violle C, Navas M L, Vile D, et al.2007. Let the concept of trait be functional! Oikos, 116(5): 882-892.
[49]
Wallace L L.1990. Comparative photosynthetic responses of big bluestem to clipping versus grazing. Journal of Range Management, 43(1): 58-61.
[50]
Wan H W, Bai Y F, Hooper D U, et al.2015. Selective grazing and seasonal precipitation play key roles in shaping plant community structure of semi-arid grasslands. Landscape Ecology, 30(9): 1767-1782.
[51]
Wang S P.2000. The dietary composition of fine wool sheep and plant diversity in Inner Mongolia steppe. Acta Ecologica Sinica, 20(6): 951-957. (in Chinese)
[52]
Wang X T, Wang W, Liang C Z.2009. Changes in the population spatial distribution pattern of Leymus chinensis in degraded steppe community during restorative succession in Inner Mongolia, China. Chinese Journal of Applied Ecology, 33(1): 63-70. (in Chinese)
[53]
Wang Z, Deng X Z, Song W, et al.2017. What is the main cause of grassland degradation? A case study of grassland ecosystem service in the middle-south Inner Mongolia. Catena, 150: 100-107.
[54]
Xu D Q.1997. Some problems in stomatal limitation analysis of photosynthesis. Plant Physiology Communications, 33(4): 241-244. (in Chinese)
[55]
Yan X, Gong J R, Zhang Z Y, et al.2013. Responses of photosynthetic characteristics of Stipa baicalensis to grazing disturbance. Chinese Journal of Plant Ecology, 37(6): 530-541. (in Chinese)
[56]
Ye Z P.2007. A new model for relationship between irradiance and the rate of photosynthesis in Oryza sativa. Photosynthetica, 45(4): 637-640.
[57]
Zangerl A R, Hamilton J G, Miller T J, et al.2002. Impact of folivory on photosynthesis is greater than the sum of its holes. Proceedings of the National Academy of Sciences of the United States of America, 99(2): 1088-1091.
[58]
Zhang L R, Niu H S, Wang S P, et al.2010. Effects of temperature increase and grazing on stomatal density and length of four alpine Kobresia meadow species, Qinghai-Tibetan Plateau. Acta Ecologica Sinica, 30(24): 6961-6969. (in Chinese)
[59]
Zhao W, Chen S P, Han X G, et al.2009. Effects of long-term grazing on the morphological and functional traits of Leymus chinensis in the semiarid grassland of Inner Mongolia, China. Ecological Research, 24(1): 99-108.
[60]
Zheng S X, Lan Z C, Li W H, et al.2011. Differential responses of plant functional trait to grazing between two contrasting dominant C3 and C4 species in a typical steppe of Inner Mongolia, China. Plant and Soil, 340(1-2): 141-155.
[61]
Zheng S X, Li W H, Lan Z C, et al.2015. Functional trait responses to grazing are mediated by soil moisture and plant functional group identity. Scientific Reports, 5: 18163.
2018, Vol. 10 
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