Development of a phosphatase activity assay using excised plant roots
Jaya Das A B C , Nicholas Comerford A , David Wright A , Jim Marois A and Cheryl Mackowiak A
+ Author Affiliations
- Author Affiliations
A North Florida Research and Education Center, University of Florida, 155 Research Road, Quincy, FL 32351-5677, USA.
B Present address: Wright State University, 268 Brehm Lab, 3640 Colonel Glenn Highway, Dayton, OH 45435, USA.
C Corresponding author. Email: das.29@wright.edu
Soil Research 52(2) 193-202 https://doi.org/10.1071/SR13198
Submitted: 9 July 2013 Accepted: 6 November 2013 Published: 6 March 2014
Abstract
Root phosphatase mediated mineralisation of organic phosphorus (P) can affect P availability in agricultural and forest landscapes. Phosphatases hydrolyse organic P into inorganic P that can be taken up by plants. We developed a method to determine mineralisable organic P by phosphatases exuded by excised live roots/microbial systems. We used excised greenhouse- and field-grown roots with para-nitrophenylphosphate, glucose-1-phosphate and phytic acid as sources of organic P. Experimental variables were analysed including linearity of the reaction, presence of inorganic P, organic P exuded from roots, possible abiotic degradation of organic P, and background inorganic/organic P. Organic P mineralisation by root–phosphatase complexes was found to be linear through 6 h. Phosphorus contaminants into the system were found to be within 10% of mineralised organic P. We used this technique to answer questions about organic P bioavailability, including effect of organic P sources, plant species, plant variety, plant stress and root conditions. Overall, this method was sensitive to organic P source and plant stress of greenhouse and field-grown roots, plant species and root physiological conditions. Unlike other methods used to determine phosphatase activity, this method is not limited by lengthy preparation to develop model plants, nor is there any restriction on the choice of organic P or plant species. Our results suggest that this is an attractive method for determining organic P mineralisation specificity among and within plant species, and it can be easily integrated into routine laboratory analyses.
Additional keywords: bahiagrass, bioavailability, cotton, excised roots, glucose-1-phosphate, mineralisation, organic phosphorus, peanut, phosphatase activity, phytic acid, para-nitrophenylphosphate, Q10.
References
Amador JA, Glucksman AM, Lyons JB, Gorres JH (1997) Spatial distribution of soil phosphatase activity within a riparian forest. Soil Science 162, 808–825.| Spatial distribution of soil phosphatase activity within a riparian forest.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK2sXnslOku7w%3D&md5=21dfc7f5432e489ee9047eec573fbecaCAS |
Antibus RK, Bower D, Dighton J (1997) Root surface phosphatase activities and uptake of 32P-labelled inositol phosphate in field-collected gray birch and red maple roots. Mycorrhiza 7, 39–46.
| Root surface phosphatase activities and uptake of 32P-labelled inositol phosphate in field-collected gray birch and red maple roots.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK2sXksVWqtr8%3D&md5=9c24768daf20477da8e5ecc938275d9eCAS |
Baggie I, Rowell DL, Warren GP, Robinson JS (2004) Utilization by upland rice of plant residue- and fertilizer-phosphorus in two tropical acid soils. Nutrient Cycling in Agroecosystems 69, 73–84.
| Utilization by upland rice of plant residue- and fertilizer-phosphorus in two tropical acid soils.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2cXjtlyjt74%3D&md5=caa5361a65a0590a014f8987be458f8bCAS |
Bentzen E, Taylor WD (1991) Estimating organic P utilization by freshwater plankton using [32P] ATP. Journal of Plankton Research 13, 1223–1238.
| Estimating organic P utilization by freshwater plankton using [32P] ATP.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK38XhvVaitQ%3D%3D&md5=28f3226527a3c6198e1cf52d019b52d0CAS |
Bishop ML, Chang AC, Lee RWK (1994) Enzymatic mineralization of organic phosphorus in a volcanic soil in Chile. Soil Science 157, 238–243.
| Enzymatic mineralization of organic phosphorus in a volcanic soil in Chile.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK2cXjt1ajt7c%3D&md5=51c1a91f24da6b1b964efc59c945ffd3CAS |
Björkman K, Karl DM (1994) Bioavailability of inorganic and organic phosphorus compounds to natural assemblages of microorganisms in Hawaiian coastal waters. Marine Ecology Progress Series 111, 265–273.
| Bioavailability of inorganic and organic phosphorus compounds to natural assemblages of microorganisms in Hawaiian coastal waters.Crossref | GoogleScholarGoogle Scholar |
Bolland MDA, Guthridge IF (2007) Determining the fertilizer phosphorus requirements of intensively grazed dairy pastures in south-western Australia with or without adequate nitrogen fertilizer. Australian Journal of Experimental Agriculture 47, 801–814.
| Determining the fertilizer phosphorus requirements of intensively grazed dairy pastures in south-western Australia with or without adequate nitrogen fertilizer.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2sXnsV2gsbs%3D&md5=04b5da6c2154d7638730704cdac664ebCAS |
Bouma TJ, Yanai RD, Elkin AD, Hartmond U, Flores-Alva DE, Eissenstat DM (2001) Estimating age-dependent cost and benefits of roots with contrasting life span: comparing apples and oranges. New Phytologist 150, 685–695.
| Estimating age-dependent cost and benefits of roots with contrasting life span: comparing apples and oranges.Crossref | GoogleScholarGoogle Scholar |
Bowman RA, Cole CV (1978) Transformations of organic phosphorus substrates in soils as evaluated by NaHCO3 extraction. Soil Science 125, 49–54.
| Transformations of organic phosphorus substrates in soils as evaluated by NaHCO3 extraction.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaE1cXovVagtQ%3D%3D&md5=9d028c50f3c62c6f2450bf03c74f922aCAS |
Bünemann EK, Marschner P, McNeill AM, McLaughlin MJ (2007) Measuring rates of gross and net mineralization of organic phosphorus in soils. Soil Biology & Biochemistry 39, 900–913.
| Measuring rates of gross and net mineralization of organic phosphorus in soils.Crossref | GoogleScholarGoogle Scholar |
Bünemann EK, Oberson A, Frossard E (2011) ‘Phosphorus in action: Biological processes in soil phosphorus cycling’. (Springer-Verlag: Berlin)
Bybordi A, Ebrahimian E (2011) Effect of salinity stress on activity of enzymes involved in nitrogen and phosphorous metabolism case study: canola (Brassica napus L.). Asian Journal of Agricultural Research 5, 208–214.
| Effect of salinity stress on activity of enzymes involved in nitrogen and phosphorous metabolism case study: canola (Brassica napus L.).Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3MXht1Clu73J&md5=817cbaed17cc2b0ac49b1a9a6357d993CAS |
Clinebell RR, Phillips OL, Stark N, Zuuring H (1995) Prediction of neotropical tree and liana species richness from soil and climatic data. Biodiversity and Conservation 4, 56–90.
| Prediction of neotropical tree and liana species richness from soil and climatic data.Crossref | GoogleScholarGoogle Scholar |
Comas LH, Eissenstat DM, Lakso AN (2000) Assessing root death and root system dynamics in a study of grape canopy pruning. New Phytologist 147, 171–178.
| Assessing root death and root system dynamics in a study of grape canopy pruning.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD3cXms1yltLw%3D&md5=e78f504c2a125cb0fe1e92c1b7382315CAS |
Condron LM, Tiessen H (2005) Interactions of organic phosphorus in terrestrial ecosystems. In ‘Organic phosphorus in the environment’. (Eds BL Turner, E Frossard, DS Baldwin) pp. 295–308. (CAB International: Wallingford, UK)
Cordell D, Drangert JO, White S (2009) The story of phosphorus: Global food security and food for thought. Global Environmental Change 19, 292–305.
| The story of phosphorus: Global food security and food for thought.Crossref | GoogleScholarGoogle Scholar |
Cotner JB, Wetzel RG (1992) Uptake of dissolved inorganic and organic phosphorus compounds by phytoplankton and bacterioplankton. Limnology and Oceanography 37, 232–243.
| Uptake of dissolved inorganic and organic phosphorus compounds by phytoplankton and bacterioplankton.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK38XlsFOitbs%3D&md5=e059849ea07e9c894235b05c0cc68311CAS |
Environmental Protection Agency (1993) Method 365.1–12: Determination of phosphorus by semi-automated colorimetry. U.S. Environmental Protection Agency. Available at: http://water.epa.gov/scitech/methods/cwa/bioindicators/upload/2007_07_10_methods_method_365_1.pdf
Espeland EM, Wetzel RG (2001) Effects of photosynthesis on bacterial phosphatase production in biofilms. Microbial Ecology 42, 328–337.
| Effects of photosynthesis on bacterial phosphatase production in biofilms.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD38Xks1Y%3D&md5=09d812a56d25f3686a3da6cdd6b375fdCAS | 12024258PubMed |
Feng G, Song YD, Li XL, Christie P (2003) Contribution of arbuscular mycorrihizal fungi to utilization of organic sources of phosphorus by red clover in a calcareous soil. Applied Soil Ecology 22, 139–148.
| Contribution of arbuscular mycorrihizal fungi to utilization of organic sources of phosphorus by red clover in a calcareous soil.Crossref | GoogleScholarGoogle Scholar |
Firsching BM, Classen N (1996) Root phosphatase activity and soil organic phosphorus utilization by Norway spruce. Soil Biology & Biochemistry 28, 1417–1424.
| Root phosphatase activity and soil organic phosphorus utilization by Norway spruce.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK2sXos1aksg%3D%3D&md5=a065becb3646954002369b06b09d112cCAS |
Fox TR, Comerford NB (1992) Rhizosphere phosphatase activity and phosphatase hydrolyzable organic phosphorus in two forested Spodosols. Soil Biology & Biochemistry 24, 579–583.
| Rhizosphere phosphatase activity and phosphatase hydrolyzable organic phosphorus in two forested Spodosols.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK38XltlSntrc%3D&md5=3e25c6db90611f72f5ddcef87b2b3231CAS |
Gilbert GA, Knight JD, Vance CP, Allan DL (1999) Acid phosphatase activity in phosphorus-deficient white lupin roots. Plant, Cell & Environment 22, 801–810.
| Acid phosphatase activity in phosphorus-deficient white lupin roots.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK1MXlsFGnsr8%3D&md5=7e629e3263a2fa8327958422bb645651CAS |
Glibert PM, Heil CA, Hollander D, Revilla M, Hoare A, Alexander J, Murasko S (2004) Evidence for dissolved organic nitrogen and phosphorus uptake during a cyanobacterial bloom in Florida Bay. Marine Ecology Progress Series 280, 73–83.
| Evidence for dissolved organic nitrogen and phosphorus uptake during a cyanobacterial bloom in Florida Bay.Crossref | GoogleScholarGoogle Scholar |
Graham D, Patterson BD (1982) Responses of plants to low, nonfreezing temperatures: proteins, metabolism, and acclimation. Annual Review of Plant Physiology 33, 347–372.
| Responses of plants to low, nonfreezing temperatures: proteins, metabolism, and acclimation.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaL38Xkt1SltrY%3D&md5=44a8f42658b71ce196a705f0dee962e6CAS |
Hartemink AE (2003) Soil fertility decline in the tropics: with case studies on plantations. In ‘Soil fertility decline in the tropics: with case studies on plantations’. (Ed. AE Hartemink) (CABI International: Wallingford, UK)
Hartemink AE (2006) Assessing soil fertility decline in the tropics using soil chemical data. Advances in Agronomy 89, 179–225.
| Assessing soil fertility decline in the tropics using soil chemical data.Crossref | GoogleScholarGoogle Scholar |
Helal HM (1990) Varietal differences in root phosphatase activity as related to the utilization of organic phosphates. Plant and Soil 123, 161–163.
| Varietal differences in root phosphatase activity as related to the utilization of organic phosphates.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK3cXkvFKlsrg%3D&md5=8169624e7cbc670a3ea04c82b6f6f0a2CAS |
Hernandez I, Hwang SA, Heath RT (1996) Measurement of phosphomonoesterase activity with a radiolabelled glucose-6-phosphate: role in the phosphorus requirement of phytoplankton and bacterioplankton in a temperate mesotrophic lake. Archiv fuer Hydrobiologie 137, 265–280.
Johnson AH, Frizano J, Vann DR (2003) Biogeochemical implications of labile phosphorus in forest soils determined by the Hedley fractionation procedure. Oecologia 135, 487–499.
Juma NG, Tabatabai MA (1988) Hydrolysis of organic phosphates by corn and soybean roots. Plant and Soil 107, 31–38.
| Hydrolysis of organic phosphates by corn and soybean roots.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaL1cXksFWkurc%3D&md5=4c24d87708dffda933216de8d901de02CAS |
MacFall J, Slacks A, Iyer J (1991) Effects of Hebeloma arenosa and phosphorus fertility on root acid phosphatase activity of red pine (Pinus resinosa) seedlings. Canadian Journal of Botany 69, 380–383.
| Effects of Hebeloma arenosa and phosphorus fertility on root acid phosphatase activity of red pine (Pinus resinosa) seedlings.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK3MXitVKjtrw%3D&md5=200195bfbb14d3d214d66917c50095f5CAS |
Malik MA, Petra M, Saifullah KK (2012) Addition of organic and inorganic P sources to soil—effects on P pools and microorganisms. Soil Biology & Biochemistry 49, 106–113.
| Addition of organic and inorganic P sources to soil—effects on P pools and microorganisms.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC38Xlt1Okurc%3D&md5=30ed44e44f256c3a4097b2fa2d92d89bCAS |
McLachlan KD (1980) Acid phosphatase activity of intact roots and phosphorus nutrition in plants. I. Assay conditions and phosphatase activity. Australian Journal of Agricultural Research 31, 429–440.
| Acid phosphatase activity of intact roots and phosphorus nutrition in plants. I. Assay conditions and phosphatase activity.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaL3cXks12mt7k%3D&md5=e2847dab1e2065cf85fc540d60803e7dCAS |
Murphy J, Riley JP (1962) A modified single solution method for the determination of phosphate in natural waters. Analytica Chimica Acta 27, 31–36.
| A modified single solution method for the determination of phosphate in natural waters.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaF38XksVyntr8%3D&md5=17ea13f1f165a05bfa49825c9e608460CAS |
Oehl F, Oberson A, Sinaj A, Frossard E (2001) Organic phosphorus mineralization studies using isotopic dilution techniques. Soil Science Society of America Journal 65, 780–787.
| Organic phosphorus mineralization studies using isotopic dilution techniques.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD3MXntFWktLc%3D&md5=c69cdd629d1e50bd68655ec610b4a606CAS |
Pierre WH, Parker FW (1927) The concentration of organic and inorganic phosphorus in the soil solution and soil extracts and the availability of organic phosphorus of plants. Soil Science 24, 119–128.
| The concentration of organic and inorganic phosphorus in the soil solution and soil extracts and the availability of organic phosphorus of plants.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaB1cXisFymug%3D%3D&md5=e3165fe5c69734cc2a54f5695e08c12bCAS |
Poorter H, Bühler J, Dusschoten D, Climent J, Postma JA (2012) Pot size matters: a meta-analysis of the effects of rooting volume on plant growth. Functional Plant Biology 39, 839–850.
| Pot size matters: a meta-analysis of the effects of rooting volume on plant growth.Crossref | GoogleScholarGoogle Scholar |
Richardson A (1994) Soil microorganisms and phosphorus availability. In ‘Soil biota: Management in sustainable farming systems’. (Eds CE Pankhurst, BM Doube, VVSR Gupta, PR Grace) pp. 50–62. (CSIRO: East Melbourne)
Richardson AE, Simpson RJ (2011) Soil microorganisms mediating phosphorus availability. Plant Physiology 156, 989–996.
| Soil microorganisms mediating phosphorus availability.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3MXptFWlurw%3D&md5=d7fd7a69d709dcbe7f07a3b5e3ee01fcCAS | 21606316PubMed |
Rogers HT, Pearson RW, Pierre WH (1941) Absorption of organic phosphorus by corn and tomato plants and the mineralizing action of exo-enzyme systems of growing roots. Soil Science Society of America Journal 5, 285–291.
| Absorption of organic phosphorus by corn and tomato plants and the mineralizing action of exo-enzyme systems of growing roots.Crossref | GoogleScholarGoogle Scholar |
Rojo MJ, Carcedo SJ, Mateos MP (1990) Distribution and characterization of phosphatase and organic phosphorus in soil fractions. Soil Biology & Biochemistry 22, 169–174.
| Distribution and characterization of phosphatase and organic phosphorus in soil fractions.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK3cXktVGisbo%3D&md5=db590cf7ad3430dabeadf37fda776b97CAS |
Rose AR (1912) The influence of phytin on seedlings. Science 35, 393
Saifuzzaman M, Rawson HM, Hossain AB, Amin S, Sarker MA, Ullah MH, Farhad M, Hossain MF, Roy K (2011) ‘Fertilizer and water requirements for southern wheat crops. Australian Centre for International Agricultural Research Technical Reports Series No. 78.’ (ACIAR: Canberra)
Salisbury FB, Ross C (1969) ‘Plant physiology.’ (Wadsworth Publishing: Belmont, CA, USA)
Schachtman DP, Reid RJ, Ayling SM (1998) Phosphorus uptake by plants: from soil to cell. Plant Physiology 116, 447–453.
| Phosphorus uptake by plants: from soil to cell.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK1cXht1ajtbc%3D&md5=9f10555faaef86023d75fc2d349f1cd5CAS | 9490752PubMed |
Sebastián M, Pitta P, González JM, Thingstad TF, Gasol JM (2012) Bacterioplankton groups involved in the uptake of phosphate and dissolved organic phosphorus in a mesocosm experiment with P-starved Mediterranean waters. Environmental Microbiology 14, 2334–2347.
| Bacterioplankton groups involved in the uptake of phosphate and dissolved organic phosphorus in a mesocosm experiment with P-starved Mediterranean waters.Crossref | GoogleScholarGoogle Scholar | 22564346PubMed |
Sharma AD, Thakur M, Rana M, Singh K (2004) Effect of plant growth hormones and abiotic stresses on germination, growth and phosphatase activities in Sorghum bicolor (L.) Moench seeds. African Journal of Biotechnology 3, 308–312.
Shibata R, Yano K (2003) Phosphorus acquisition from non-labile sources in peanut and pigeonpea with mycorrhizal interaction. Applied Soil Ecology 24, 133–141.
| Phosphorus acquisition from non-labile sources in peanut and pigeonpea with mycorrhizal interaction.Crossref | GoogleScholarGoogle Scholar |
Sinsabaugh RL, Saiya-Cork K, Long T, Osgood MP, Neher DA, Zak DR, Norby RJ (2003) Soil microbial activity in a Liquidambar plantation unresponsive to CO2-driven increases in primary production. Applied Soil Ecology 24, 263–271.
| Soil microbial activity in a Liquidambar plantation unresponsive to CO2-driven increases in primary production.Crossref | GoogleScholarGoogle Scholar |
Soil Survey Staff (1999) ‘Soil taxonomy: a basic system of soil classification for making and interpreting soil surveys. USDA Agriculture Handbook no. 436.’ (US Government Printing Office: Washington, DC)
StatSoft Inc. (2011) ‘Statistica (data analysis software system), version 10.’ (StatSoft: Tulsa, OK, USA) www.statsoft.com
Stoorvogel JJ, Smaling EMA (1998) Research on soil fertility decline in tropical environments: integration of spatial scales. Nutrient Cycling in Agroecosystems 50, 151–158.
Sun CH, Du W, Cheng XL, Xu XN, Zhang YH, Sun D, Shi JJ (2010) The effects of drought stress on the activity of acid phosphatase and its protective enzymes in pigweed leaves. African Journal of Biotechnology 9, 825–833.
Tanner EVJ, Vitousek PM, Cuevas E (1998) Experimental investigation of nutrient limitation of forest growth on wet tropical mountains. Ecology 79, 10–22.
| Experimental investigation of nutrient limitation of forest growth on wet tropical mountains.Crossref | GoogleScholarGoogle Scholar |
Tarafdar JC, Jungk A (1987) Phosphatase activity in the rhizosphere and its relation to the depletion of soil organic phosphorus. Biology and Fertility of Soils 3, 199–204.
| Phosphatase activity in the rhizosphere and its relation to the depletion of soil organic phosphorus.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaL2sXlslGjtrs%3D&md5=248190456b4eaf33c046f92e60381166CAS |
Tarafder JC, Classen N (1988) Organic phosphorus compounds as a phosphorus source for higher plants through the activity of phosphatases produced by plant roots and microorganisms. Biology and Fertility of Soils 5, 308–312.
Tate K, Salcedo R (1988) Phosphorus control of soil organic matter accumulation and cycling. Biogeochemistry 5, 99–107.
| Phosphorus control of soil organic matter accumulation and cycling.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaL1cXhvVGls7c%3D&md5=9a9cc6bec4ba16f58cc476bcfaa144f5CAS |
Vitousek PM, Sanford RLJ (1986) Nutrient cycling in moist tropical forest. Annual Review of Ecology Evolution and Systematics 17, 137–167.
| Nutrient cycling in moist tropical forest.Crossref | GoogleScholarGoogle Scholar |
Vitousek PM, Porder S, Houlton BZ, Chadwick OA (2010) Terrestrial phosphorus limitation: mechanisms, implications, and nitrogen-phosphorus interactions. Ecological Applications 20, 5–15.
| Terrestrial phosphorus limitation: mechanisms, implications, and nitrogen-phosphorus interactions.Crossref | GoogleScholarGoogle Scholar | 20349827PubMed |
Volder A, Smart DR, Bloom AJ, Eissenstat D (2005) Rapid decline in nitrate uptake and respiration with age in fine lateral roots of grape: implications for root efficiency and competitive effectiveness. New Phytologist 165, 493–502.
| Rapid decline in nitrate uptake and respiration with age in fine lateral roots of grape: implications for root efficiency and competitive effectiveness.Crossref | GoogleScholarGoogle Scholar | 15720660PubMed |
Wang X, Tang C, Guppy CN, Sale PWG (2008) Phosphorus acquisition characteristics of cotton (Gossypium hirsutum L.), wheat (Triticum aestivum L.) and white lupin (Lupinus albus L.) under P deficient conditions. Plant and Soil 312, 117–128.
| Phosphorus acquisition characteristics of cotton (Gossypium hirsutum L.), wheat (Triticum aestivum L.) and white lupin (Lupinus albus L.) under P deficient conditions.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD1cXht1aju7nI&md5=29e0fa700513c3ff72faa4fef0ac7ca0CAS |
Wells CE, Eissenstat DM (2001) Marked difference in survivorship among apple roots of different diameter. Ecology 82, 882–892.
| Marked difference in survivorship among apple roots of different diameter.Crossref | GoogleScholarGoogle Scholar |
Wells CE, Eissenstat DM (2002) Beyond the roots of young seedlings: the influence of age and order on fine root physiology. Journal of Plant Growth Regulation 21, 324–334.
| Beyond the roots of young seedlings: the influence of age and order on fine root physiology.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD3sXlslWnt7c%3D&md5=c6ae0c4b5e6a27e24c78e70b7c6eca2bCAS |
Zhang W (1991) Path analysis and relative availability of inorganic and organic phosphorus fractions in soils. Acta Pedologica Sinica 28, 417–425.
