Effect of Potassium Application on Root Growth and Yield of Sweet Potato and Its Physiological Mechanism

WANG Shun-Yi1 LI Huan1 LIU Qing1 SHI Yan-Xi1

(1.College of Resources and Environmental Science, Qingdao Agricultural University, Qingdao, China 266109)

【Abstract】The objective of this study was to investigate the physiological mechanism of potassium application on root growth and yield improvement in sweet potato. Two year field experiment was conducted with three potassium levels (0 kg hm−2, 75 kg hm−2, 150 kg hm−2, and 225 kg hm−2) to study the effects of potassium on root growth, 13C distribution, metabolic enzyme activity, photosynthetic characteristics and yield of sweet potato. Compared with CK, potassium treatments increased ETR by 12.7%–63.6%, and Pn by 7.2%–26.4%. Potassium application improved photosynthetic characteristics and accelerated the accumulation of photosynthate, providing material basis for root growth. However, potassium application was beneficial to the photosynthate products from shoots to roots, and root 13C distribution amount increased by 10.6%–66.2% (P < 0.05). Then, potassium application increased sucrose synthase, sucrose phosphate synthase and adenosine diphosphate glucose pyrophosphorylase activities and accelerated the assimilation of carbon in roots, thus improving the photosynthate accumulation in roots and promoting root differentiation and growth in sweet potato. In early growing stage, potassium application increased total root length by 13.6% –22.8% and the average diameter of root by 11.3%–51.9%, and significantly increased the differentiation from adventitious roots to fibrous roots and tuberous roots (P < 0.05), which was beneficial to the early formation of effective tuberous root, ensuring the effective number of tuberous roots per plant. Potassium treatments increased the root biomass and average tuberous root weight. Compared with CK, the potassium treatments increased yields by 5.8%, 24.3%, and 44.7% in 2014, and by 7.9%, 13.4%, and 22.8% in 2015, respectively.

【Keywords】 Sweet potato; Root growth; Photosynthetic characteristics; 13C distribution; C enzyme activities;

【Funds】 China Agriculture Research System (CARS-11-B-14) supported by the National Modern Agro-industry Technology System (CARS-11-B-14) Young Scientists Fund of the National Natural Science Foundation of China (31301854) the Natural Science Foundation for Young Scientists of China (31301854)

Download this article

(Translated by PAN Yu)


    [1]Wang C J, Shi C Y, Wang Z Z, Chai S S, Liu H J, Shi Y X. Effects of plastic film mulching cultivation on young roots growth development, tuber formation and tuber yield of sweet potato. Acta Agron Sin, 2014, 40: 1677–1685 (in Chinese with English abstract)

    [2]Pervez H, Ashraf M, Makhdum M I. Influence of potassium nutrition on gas exchange characteristics and water relations in cotton (Gossypium hirsutum L.) . Photosynthetica, 2001, 42: 251–255

    [3]Lebaudy A, Vavasseur A, Hosy E, Dreyer I, Leonhardt N, Thibaud J B, Very A A, Simonneau T, Sentenac H. Plant adaptation to fluctuating environment and biomass production are strongly dependent on guard cell potassium channels. Proc Natl Acad Sci USA, 2008, 105: 5271–5276

    [4]Han Q. Height-related decreases in mesophyll conductance, leaf photosynthesis and compensating adjustments associated with leaf nitrogen concentrations in Pinus densiflora. Tree Physiol, 2011, 31: 976–984

    [5]Pettigrew W T. Potassium influences on yield and quality production for maize, wheat, soybean and cotton. Physiol Plant, 2008, 133: 670–681

    [6]Ning Y W, Cao B G, Zhu L D, Zhang Y C, Wang J D, Xu X J, Zhang H, Ma H B. Effects of potassium application rates on dry matter accumulation, dry matter distribution, and potassium efficiency of sweet potato. Jiangsu Agric Sci, 2012, 28: 320–325 (in Chinese with English abstract)

    [7]Hammett L K, Miller C H, Swallow W H, Harden C. Influence of N source, N rate, and K rate on the yield and mineral concentration of sweet potato. J Am Soc Hort Sci, 1984, 109: 294–298

    [8]Shi C Y, Wang Z L, Zhao B Q, Guo F F, Yu S L. Effect of potassium nutrition on some physiological characteristics and yield formation of sweet potato. Plant Nutr Fert Sci, 2002, 8: 81–85 (in Chinese with English abstract)

    [9]Li W L, Xiong J, Tang X H, Yan H F, Zheng X, Wei M Z, Qin W Z, Xu J. Effects of potassium application rate on yield formation and potassium utilization efficiency of starchy sweet potato variety Xushu 26. Chin J Trop Crops, 2015, 36: 1037–1042 (in Chinese with English abstract)

    [10]Wang D Z, Liu X P, Zhong K l, Guo Z B, Tian M S. Study on Optimum potassium rate application on sweet potato in Shajiang black soil in Anhui province. Crops, 2014, (5) : 109–112 (in Chinese with English abstract)

    [11]Foloni J S S, Corte A J, Corte J R D N, Fabio R E, Carlos S T. Topdressing fertilization with nitrogen and potassium levels in sweet-potato. Semina Ciências Agrárias, 2013, 34: 117–126 (in Portuguese with English abstract)

    [12]Ning Y W, Ma H B, Zhang H, Xu J P, Wang J D, Xu X J, Zhang Y C. Effects of nitrogen, phosphorus and potassium on root morphology and endogenous hormone contents of sweet potato at early growing stages. Jiangsu Agric Sci, 2013, 29: 1326–1332 (in Chinese with English abstract)

    [13]Qi H P, An X, Liu Y, Zhu G P, Wang J D, Zhang Y C. Effects of potassium application rates on yield, potassium uptake and utilization in sweet potato genotypes. Jiangsu Agric Sci, 2016, 32: 84–89 (in Chinese with English abstract)

    [14]Bao S D. 土壤农化分析. Beijing: China Agricultural Press, 2000. pp 12–18 (in Chinese)

    [15]Hironaka K, Ishibashi K, Hakamada K. Effect of static loading on sugar contents and activities of invertase, UDP-glucose pyrophosphorylase and sucrose 6-phosphate synthase in potatoes during storage. Potato Res, 2001, 44: 33–39

    [16]Li P M, Gao H Y, Strasser R J. Application of the fast chlorophyll fluorescence induction dynamics analysis in photosynthesis study. J Plant Physiol Mol Biol, 2005, 31: 559–566 (in Chinese with English abstract)

    [17]Noh S A, Lee H S, Kim Y S, Paek K H, Shin J S, Bae J M. Down-regulation of the IbEXP1 gene enhanced storage root development in sweet potato. J Exp Bot, 2013, 64: 129–142

    [18]Jiangsu Academy of Agricultural Sciences and Shandong Academy of Agricultural Sciences. 中国甘薯栽培学, Shanghai: Scientific and Technical Publisher, 1984. pp 41–45 (in Chinese)

    [19]Zou C Q, Li Z S, Li J Y. Study on difference in morpholofical and physiological characters of wheat varieties to potassium. Plant Nutr Fert Sci, 2001, 7: 36–43 (in Chinese with English abstract)

    [20]Pan Y H, Ma Z M, Lyu X D, Du S P, Xue L. Effects of different potassium nutrition on growth and root morphological traits of watermelon seedling. Chin J Eco-Agric, 2012, 20: 536–541 (in Chinese with English abstract)

    [21]Ning Y W, Ma H B, Xu X J, Wang J D, Zhang H, Xu J P, Chen J, Zhang Y C. Effects of deficiency of N, P, or K on growth traits and nutrient uptakes of sweet potato at early growing stage. Sci Agric Sin, 2013, 46: 486–495 (in Chinese with English abstract)

    [22]Fan W G, Yang H Q. Response of root architecture, nutrients uptake and shoot growth of Malus hupehensis seedling to the shape of root zone. Sci Agric Sin, 2014, 47: 3907–3913 (in Chinese with English abstract)

    [23]Shcansker G, Srivastava A, Covindjee, Strasser R J. Characterization of the 820-nm transmission signal paralleling the chlorophyll a fluorescence rise (OJIP) in pea leaves. Funct Plant Biol, 2003, 30: 785–796

    [24]Yu G S, Liu B, Wang L F, Li M H, Liu Y. Damage to the oxygen-evolving complex by superoxide anion, hydrogen peroxide, and hydroxyl radical in photoinhibition of photosystem II. Photosynth Res, 2006, 90: 67–78

    [25]Strasser R J, Srivastava A, Covindjee. Ployphasic chlorophyll a fluorescence transients in plants and cyanobacteria. Photochem Photobiol, 1995, 61: 32–42

    [26]Sun J W, Li S F, Fu X S, Xi H, Wang T H. Effects of low potassium stress on photosynthetic characteristics and antioxidant systems in different position leaves of rice plants. J Nucl Agric Sci, 2006, 21: 404–408 (in Chinese with English abstract)

    [27]Gilmore A M, Hazlett T L, Debrunner P G. Comparative time-resolved photosystem II chlorophyll a fluorescence analyses reveal distinctive differences between photoinhibitory reaction center damage and xanthophyll cycle-dependent energy dissipation. Photochem Photobiol, 1996, 64: 552–563

    [28]Sun J W, Weng X Y, Li Q, Shao J L. Effects of potassium-deficiency on photosynthesis and energy dissipation in different rice cultivars. Plant Nutr Fert Sci, 2007, 13: 577–584 (in Chinese with English abstract)

    [29]Lalonde S, Wipf D, Frommer W B. Transport mechanisms for organic forms of carbon and nitrogen between source and sink. Annu Rev Plant Biol, 2004, 55: 341–372

    [30]Turgeon R. The role of phloem loading reconsidered. Plant Physiol, 2010, 152: 1817–1123

    [31]Chen X G, Shi C Y, Li H M, Zhang A J, Shi X M, Tang Z H, Wei M. Effects of potassium fertilization period on photosynthetic characteristics and storage root starch accumulation of edible sweet potato. Chin J Appl Ecol, 2013, 24: 759–763 (in Chinese with English abstract)

    [32]Wang C J, Shi C Y, Liu N, Liu S R, Yu X D. Comparison of root characteristics and sugar components in root and leaf at early growth phase of sweet potato varieties with significant difference in valid storage root number. Acta Agron Sin, 2016, 42: 131–140 (in Chinese with English abstract)

    [33]Ning Y W, Ma H B, Zhang H, Wang J D, Xu J X, Zhang Y C. Response of sweet potato in source-sink relationship establishment, expanding, and balance to nitrogen application rates. Acta Agron Sin, 2015, 41: 432–439 (in Chinese with English abstract)

This Article


CN: 11-1809/S

Vol 43, No. 07, Pages 1057-1066

July 2017


Article Outline



  • 1 Materials and methods
  • 2 Results and analysis
  • 3 Discussion
  • 4 Conclusions
  • References