APase Activity In Roots Research Articles

Root morphological and physiological traits are committed to the phosphorus acquisition of the desert plants in phosphorus-deficient soils

BackgroundPhosphorus (P) deficiency in desert ecosystems is widespread. Generally, desert species may allocate an enormous proportion of photosynthetic carbon to their root systems to adjust their P-acquisition strategies. However, root P-acquisition strategies of deep-rooted desert species and the coordination response of root traits at different growth stages to differing soil P availability remains unclear. In this study, a two-year pot experiment was performed with four soil P-supply treatments (0, 0.9, 2.8, and 4.7 mg P kg–1 y–1 for the control, low-, intermediate-, and high-P supply, respectively). Root morphological and physiological traits of one- and two-year-old Alhagi sparsifolia seedlings were measured.ResultsFor two-year-old seedlings, control or low-P supply significantly increased their leaf Mn concentration, coarse and fine roots’ specific root length (SRL), specific root surface area (SRSA), and acid phosphatase activity (APase), but SRL and SRSA of one-year-old seedlings were higher under intermediate-P supply treatment. Root morphological traits were closely correlated with root APase activity and leaf Mn concentration. One-year-old seedlings had higher root APase activity, leaf Mn concentration, and root tissue density (RTD), but lower SRL and SRSA. Two-year-old seedlings had higher root APase activity, leaf Mn concentration, SRL and SRSA, but a lower RTD. Root APase activity was significantly positively correlated with the leaf Mn concentration, regardless of coarse or fine roots. Furthermore, root P concentrations of coarse and fine roots were driven by different root traits, with root biomass and carboxylates secretion particularly crucial root traits for the root P-acquisition of one- and two-year-old seedlings.ConclusionsVariation of root traits at different growth stages are coordinated with root P concentrations, indicating a trade-off between root traits and P-acquisition strategies. Alhagi sparsifolia developed two P-activation strategies, increasing P-mobilizing phosphatase activity and carboxylates secretion, to acclimate P-impoverished in soil. The adaptive variation of root traits at different growth stages and diversified P-activation strategies are conducive to maintaining the desert ecosystem productivity.

Ameliorated light conditions increase the P uptake capability of soybean in a relay-strip intercropping system by altering root morphology and physiology in the areas with low solar radiation

Belowground interspecific facilitation and complementarity contribute to the phosphorus (P) uptake advantages in the cereal-legume intercropping system. However, the root morphological and physiological plasticity and, subsequently, the P uptake capability response to light conditions in intercropping systems remain unclear. Soybean was grown under two levels of P application rates in sole and intercropping systems (maize/soybean relay strip intercropping) from 2016 to 2018 in Renshou, southwest of China. As a supplement to the field experiment, soybean was also grown in L-S (simulating the light conditions of sole cropping in the field: light first and then shading) and S-L (simulating the light conditions of intercropping in the field: shading first and then light) light conditions with two levels of P application in 2018 in a pot experiment. After maize harvest (approximately 3/4 of the soybean growth period), light capture in intercropping was higher than sole (ameliorated light conditions in intercropping system), which resulted in an advantage of P uptake in intercropped soybean. Both low P supply and more light capture increased the total root length and root APase activity. The genes GmEXPB2 (which is associated with root growth) and GmACP1 (which is associated with exudation of APase) were highly expressed in plants that captured more light under both P-sufficient and P-deficient conditions. Additionally, more light capture increased the production of lateral roots and the proportion of in the upper 15 cm soil layer roots at the reproductive stage in the field. Across the field and pot experiments, increased root morphological and physiological plasticity were associated with lower P concentrations in the leaves and greater allocation of photosynthates to roots as sucrose. It is suggested that ameliorated light conditions can regulate soybean root growth plasticity and, consequently, P uptake in maize/soybean relay strip intercropping systems, especially in the areas with low solar radiation.

Multiple phosphorus acquisition strategies adopted by fine roots in low-fertility soils in Central Amazonia

Background and aimsAncient Amazon soils are characterised by low concentrations of soil phosphorus (P). Therefore, it is hypothesised that plants may invest a substantial proportion of their resources belowground to adjust their P-uptake strategies, including root morphological, physiological (phosphatase enzyme activities) and biotic (arbuscular mycorrhizal (AM) associations) adaptations. Since these strategies are energy demanding, we hypothesise that trade-offs between morphological traits and root phosphatase exudation and symbiotic associations would occur. Specifically, we expected that plants which invest in finer roots, and therefore have greater ability to explore large soil volumes, would have a high investment in physiological adaptations such as enhanced phosphatase production. In contrast, we expected that plants with predominantly thicker roots would invest more in symbiotic associations, in which carbon is traded for P acquired from AM fungal communities.MethodsWe collected absorptive roots (<2 mm diameter) from a lowland Central Amazon forest near Manaus, Brazil. We measured fine root diameter, specific root length (SRL), specific root area (SRA), root tissue density (RTD), root phosphatase activity (APase) and arbuscular mycorrhizal (AM) fungi colonisation.ResultsRoot morphological traits were related to APase activity, with higher APase activity in roots with higher SRL and SRA but lower RTD. However, the degree of AM colonisation was not related to any measured root morphological trait.ConclusionsFine absorptive roots likely benefit from having low RTD, high SRL, SRA and APase exudation to acquire P efficiently. However, because AM colonisation was not related to root morphology, we suggest that investment in multiple P-uptake strategies is required for maintaining productivity in Central Amazon forests.

Species interactions enhance root allocation, microbial diversity and P acquisition in intercropped wheat and soybean under P deficiency

Belowground interactions in grain legume-cereal intercrops may improve resource acquisition and adaptation to environmental constraints such as phosphorus (P) deficiency. To advance the knowledge of belowground facilitative mechanisms involved in P-deficiency tolerance (root allocation, biochemical and microbial responses), soybean (Glycine max) and wheat (Triticum aestivum) were grown as monocrops and intercrops under P-deficiency and P-sufficiency conditions in soil-filled rhizoboxes. The hypothesis was that intercropping stimulates root microbial diversity, root biomass allocation and P-hydrolyzing acid phosphatases (APase) activity in roots under P-deficient conditions. Total root dry weight (RDW), length, and surface area significantly increased in P-deficient intercropped wheat and soybean. Greater root allocation to deeper soil layers was evident for P-deficient intercropped wheat. Shallow roots of intercropped wheat exhibited highly stimulated APase activity under P-deficient conditions while shallow roots of monocropped soybean exhibited higher APase activity in comparison to deeper roots, irrespective of P treatment. Root fungal diversity was significantly (p<0.05) higher in intercropped wheat, and was significantly correlated with RDW, root APase activity, shoot P, and soil available P (ρ=0.24, p=0.01). Root bacterial diversity was higher in both intercrops, and was significantly correlated with RDW and shoot N concentration. The observed shifts in root microbial diversity, root biomass allocation and APase activity provide explanatory mechanisms of relationships between rhizosphere heterogeneity and pathways for increased P acquisition in diversified crops. Advanced belowground metabolomics on root microbial communities are required to reveal the beneficial effect of root microorganisms in associations of different crop species.

Growth, P accumulation, and physiological characteristics of two ecotypes of Polygonum hydropiper as affected by excess P supply

AbstractThe use of suitable plants that can accumulate excess phosphorus (P) from contaminated soil may serve as an attractive method for phytoremediation. In this study, pot experiments were conducted to investigate the effects of P incorporation on P accumulation and physiological mechanisms of Polygonum hydropiper in a mining ecotype (ME) and nonmining ecotype (NME) from a phosphorus mining and a noncontaminated agricultural area, respectively. The results demonstrate that the ME of P. hydropiper growing in soil supplied with 0, 100, 200, 400, 800, 1600 mg P (kg soil)–1 showed a significantly higher biomass compared to the NME. Phosphorus accumulation of the ME was positively correlated with the soil P concentration. APase activity in roots of the ME significantly increased at 1600 mg P (kg soil)–1 and phytase activity of the ME increased with increasing P supply. APase activity of the ME was more than twice that of the NME on average. A significant increase of superoxide dismutase (SOD) was observed compared with the NME at all supplied P levels. Peroxidase (POD) activity of the ME was significantly higher at 200 and 400 mg P (kg soil)–1. No statistical differences in the catalase (CAT) activity of the ME were observed compared with the control. Activity of CAT in the NME was obviously induced after exposure to 100–800 mg P (kg soil)–1. Malondialdehyde (MDA) concentration in leaves of the ME decreased with increasing P supply to reach a minimum at 400 mg P (kg soil)–1. In the NME, an increase in MDA concentration compared to the control was observed at higher P levels. The APase and phytase induction and antioxidative defense allowed for the high P accumulation of the ME.

Differential responses of oat cultivars to phosphate deprivation: plant growth and acid phosphatase activities

The effect of phosphate starvation on growth and acid phosphatases (APases) localization and activity in oat tissues was investigated. Oat cultivars (Avena sativa L.—Arab, Polar, Szakal) were grown for 1–3 weeks in complete nutrient medium (+P) and without phosphate (−P). Pi concentration in plant tissues decreased strongly after culturing on −P medium. Pi deficit reduced shoot growth, stimulated root elongation and increased ratio of root/shoot in all oat cultivars. Pi deficit had a greater impact on growth of oat cv. Polar than other varieties. A decrease in the internal Pi status led to an increase of acid phosphatase activities in extracts from shoots and roots, and in root exudates. The highest activity of secreted APases was observed for oat cv. Arab, during the third week of growth under Pi-deficient conditions. The activity of extracellular APase was high in young, growing zones of roots of −P plants. Histochemical visualization indicated high activity of APases in the epidermis and vascular tissues of −P plants. Pi deficiency increased intracellular APase activity in shoot mainly in oat cv. Polar, whereas APase activity in roots was the highest in oat cv. Szakal. Protein extracts from roots and shoots were run on native discontinuous PAGE to determine which isoform(s) may be affected by Pi deficiency. Three major APase isoforms were detected in all oat plants; one was strongly induced by Pi deficit. The studied oat cultivars differed in terms of acclimation to deficiency of phosphate—used various pools of APases to acquire Pi from external or internal sources.

Identification and molecular characterization of a low acid phosphatase 3 (lap3) mutant based on the screening of an Arabidopsis activation-tagged population

A low acid phosphatase 3 (lap3) mutant was identified and characterized from an Arabidopsis activation-tagged (Weigel) population. The roots of the lap3 plants showed lower acid phosphatase (APase) activity compared to wild-type ones under low-Pi conditions (10 μM Pi). Plasmid rescue experiments revealed that the activation-tagging vector was inserted into the intergenic region between At4g31540 and At4g31550 in the Arabidopsis genome. The genotypic segregation of the lap3 mutation was tightly linked with the phenotypic segregation of root APase activity in the prgeny of lap3. The transcript level of the At4g31520 (SDA1: SEVERE DEPOLYMERIZATION OF ACTIN 1), located 7.4 kb from the CaMV 35S enhancers in the lap3 mutant, was significantly reduced compared to that in the wild type. It was speculated that cellular actin polymerization may be involved in Pi acquisition in higher plants.

Stimulation of root acid phosphatase by phosphorus deficiency is regulated by ethylene in Medicago falcata

Plants have developed numerous strategies to cope with phosphorus (P) deficiency resulting from low availability in soils. Evolution of ethylene and up-regulation of root secreted acid phosphatase activity are common for plants in response to P deficiency. To determine the role of ethylene in response of plants to P deficiency, we investigated the effects of ethylene precursor (1-amino cyclopropane-1-carboxylic acid, ACC) and ethylene synthesis antagonists (aminoethoxyvinylglycine AVG, cobalt, Co2+) on P concentrations in roots and shoots of Medicago falcata seedlings grown in P-sufficient (500μM H2PO4−) and P-deficient (5μM H2PO4−) solution. After transferring M. falcata seedlings from P-sufficient to P-deficient solution for 2 days, root P concentration was significantly reduced. The reduction in root P concentration was reversed by AVG and Co2+, and a similar reduction in root P concentration of seedlings exposed to P-sufficient solution was observed by ACC. Expression of high-affinity phosphate transporters (MfPT1, MfPT5) was enhanced by P-deficiency and this process was reversed by AVG and Co2+. There was a marked increase in activity of root acid phosphatase (APase) and expression of gene encoding APase (MfPAP1) under P-deficient conditions, and the increase in APAse activity and expression of MfPAP1 was inhibited by AVG and Co2+. APase activity and expression of MfPAP1 expression in seedlings grown in P-sufficient solution were enhanced by ACC. Root and shoot P concentrations were increased when organic phosphorus was added to the P-deficient solution, and the increase in P concentration was significantly inhibited by AVG and Co2+. These results indicate that ethylene plays an important role in modulation of P acquisition by possibly mobilizing organic P via up-regulating root APase activity and high-affinity phosphate transporters.

The dual-targeted purple acid phosphatase isozyme AtPAP26 is essential for efficient acclimation of Arabidopsis to nutritional phosphate deprivation.

Induction of intracellular and secreted acid phosphatases (APases) is a widespread response of orthophosphate (Pi)-starved (-Pi) plants. APases catalyze Pi hydrolysis from a broad range of phosphomonoesters at an acidic pH. The largest class of nonspecific plant APases is comprised of the purple APases (PAPs). Although the biochemical properties, subcellular location, and expression of several plant PAPs have been described, their physiological functions have not been fully resolved. Recent biochemical studies indicated that AtPAP26, one of 29 PAPs encoded by the Arabidopsis (Arabidopsis thaliana) genome, is the predominant intracellular APase, as well as a major secreted APase isozyme up-regulated by -Pi Arabidopsis. An atpap26 T-DNA insertion mutant lacking AtPAP26 transcripts and 55-kD immunoreactive AtPAP26 polypeptides exhibited: (1) 9- and 5-fold lower shoot and root APase activity, respectively, which did not change in response to Pi starvation, (2) a 40% decrease in secreted APase activity during Pi deprivation, (3) 35% and 50% reductions in free and total Pi concentration, respectively, as well as 5-fold higher anthocyanin levels in shoots of soil-grown -Pi plants, and (4) impaired shoot and root development when subjected to Pi deficiency. By contrast, no deleterious influence of AtPAP26 loss of function occurred under Pi-replete conditions, or during nitrogen or potassium-limited growth, or oxidative stress. Transient expression of AtPAP26-mCherry in Arabidopsis suspension cells verified that AtPAP26 is targeted to the cell vacuole. Our results confirm that AtPAP26 is a principal contributor to Pi stress-inducible APase activity, and that it plays an important role in the Pi metabolism of -Pi Arabidopsis.

Physiological characteristics of inbred line maize seedling root under phosphorus stress

以磷高效型04419和磷低效型04065玉米自交系为材料，研究了砂培试验条件下，二者在需磷临界期（苗期）的根系生理特性差异。低磷处理下，4～8叶期磷低效型04065玉米根系酸性磷酸酶（APase）活性显著高于磷高效型04419玉米，而其根系磷含量显著低于04419，表明根系APase水平能够反映不同基因型玉米磷效率的差异。当低磷处理至6～8叶期，除根冠比外，二者根系APase、根系活力、根系丙二醛（MDA）、根系总长和干物质积累差异显著，表明不同基因型玉米对低磷的耐受能力是多种生理反应综合作用的结果。

Responses of Antioxidant Enzyme System to Copper Toxicity and Copper Detoxification in the Leaves of Elsholtzia splendens

ABSTRACT Solution culture experiments were conducted to study physiological responses to copper (Cu) toxicity and Cu detoxification involved in the antioxidant enzyme system in the leaves of Elsholtzia splendens (E. splendens). Compared with the control, 500 μM Cu considerably reduced oxidizing force and Apase activity in roots, as well as net photosynthetic rate and transpiration rate in leaves, but greatly stimulated lipid peroxidation and proline accumulation. In contrast, 50 μM Cu elevated oxidizing force and Apase activity in roots, chlorophyll content, net photosynthetic rate, and transpiration rate in leaves, and elevated proline content but decreased lipid peroxidation in the plant compared to with the control. Furthermore, at 500 μM Cu, heavily damaged organelles were found in the leaf cell of E. splendens, while at 50 μM Cu organelles were not markedly affected. These results indicate that greater oxidative stresses were induced at 500 μM Cu than at 50 μM Cu. Plants responded to Cu-induced oxidative stresses by modulating antioxidant enzymes and substrates. Compared with the control, the activities of superoxide dismutases (SOD), catalase (CAT), glutathione peroxidase (GPX), and ascorbate peroxidase (APX) in the leaves of the plant increased pronouncedly at 500 μM Cu, while at 50 μM Cu, GPX activity decreased notably and the activities of APX, SOD, and CAT changed only slightly. Copper also altered glutathione (GSH) content and glutathione reductase (GR) activity. At 50 μM Cu, both GSH content and GR activity in the leaves of the plant increased dramatically; however, at 500 μM Cu, GR activity increased but GSH content changed only slightly compared with the control. These results suggest that some adaptive physiology responses to Cu toxicity and the antioxidant enzyme system are involved in Cu detoxification in leaves of E. splendens, but at 500 μM Cu the limited activities of the antioxidant enzyme system in leaves of E. splendens make it difficult to counteract the greater oxidation stresses in vivo.

Effects of phosphate supply and elevated CO2 on root acid phosphatase activity in Pinus densiflora seedlings

AbstractThe exudation of root acid phosphatase (APase) is a plant response mechanism to phosphorus (P) deficiency. Under conditions of elevated CO2, P demand increases and possibly further enhances APase activity. We examined the activity of APase in 1‐year‐old ectomycorrhizal Pinus densiflora Sieb. et Zucc. seedlings grown in potted sand in the greenhouse under ambient (400 μmol mol–1) and elevated (700 μmol mol–1) CO2 with three modes of P supply: inorganic (NaH2PO4; Pin), organic (inositol hexaphosphate dodecasodium salt; Porg), and no phosphate (P0) for 78 d. Phosphorus limitations decreased P content in leaves and roots with lowest P content in P0 treatments, irrespective of CO2 conditions. However, P limitations decreased plant biomass at elevated CO2 levels, but not at ambient CO2 levels. The content in leaves of nutrients other than P was mostly unaffected by P supply, but decreased under elevated CO2. This observation was attributed to starch accumulation in leaves at elevated CO2, especially in the P0 treatment. The photosynthetic activity (expressed per unit of chlorophyll) was unaffected by P supply, but tended to be less at elevated CO2. There was no increase in root APase activity of Pinus densifolia in response to the P shortage caused by elevated CO2.

Rhizosphere effect and root growth of two maize ( Zea mays L.) genotypes with contrasting P efficiency at low P availability

Exploring the genetic resource of crops is one alternative way to utilize the less available phosphorus (P) in soils, and copy with the incoming shortage of rock phosphate (Rock P). Genotypic differences in low-P tolerance exist in many crop species and result from various physiological and morphological mechanisms. In this study, low-P tolerance of two maize genotypes that had been identified to have contrasting P efficiency (grain yield) in a calcareous soil was investigated. Parameters measured were biomass accumulation, root growth and root exudation of organic acids, root acid phosphatase (APase) activity, and rhizosphere pH under P-deficient (−P) and P-sufficient (+P) conditions in solution culture. The results showed that −P treatment increased root biomass (from 6th to the 15th day), root to shoot ratio, lateral root length, and APase activity in roots and on the root surface, but reduced root exudation of organic acids and pH in rhizosphere for both genotypes. The P-efficient line 181 had a larger root system in terms of root weight and lateral root length than the P-inefficient line 197 in both P treatments, indicating root morphology of line 181 is an advantageous but non-specific trait in adaptation to low P stress. Genotype 181, when grown with −P markedly reduced the pH of the solution and rizhosphere and increased the APase activity in the roots and on the root surfaces. Surprisingly, root exudation of organic acids was reduced by −P in both genotypes. Exudation rate of organic acids in 181 was lower than that of 197 under both P treatments. It was concluded that efficient use of P in the calcareous soil by 181 is related to its large root system, greater ability to acidify the rhizosphere, and positive response of APase production and excretion to low P conditions.

Differential responses of rice acid phosphatase activities and isoforms to phosphorus deprivation.

Acid phosphatases (APases) play a role in the release of phosphate in organic complexes in soil. We investigated tissue- and isoform-specific responses of APases to phosphorus (P) deficiency in three rice genotypes; Dasan-byeo, Sobi-byeo, and Palawan. The levels of shoot APase activity per protein were similar in the three genotypes. They significantly decreased with P deprivation that was longer than seven days. Root APase activity per protein was two- to three-fold higher in Dasan than in Sobi and Palawan. In all genotypes the APase activity increased in P-deficient plants, but the increase was higher in Sobi and Palawan. After 21 days of P deprivation, secreted APase activity increased more than eight-fold in Dasan and two-fold in Sobi and Palawan. Isoform profiles of shoot and root APases were most diverse in Dasan. The activities of the major isoforms in P-deficient shoots decreased in all three genotypes. Depending on the genotypes, further increases in constitutive isoforms and new induction of one to four isoforms occurred in P-deficient roots. The results indicate that tissue and genotype differences in the response of APase to P deficiency are primarily facilitated by the different responses of the isoforms.

Pho3: a phosphorus-deficient mutant of Arabidopsis thaliana (L.) Heynh.

A novel P-deficient mutant of Arabidopsis thaliana, pho3, was isolated by screening for root acid phosphatase (APase) activity in plants grown under low-P conditions. pho3 had 30% less APase activity in roots than the wild type and, in contrast to wild-type plants, root APase activity did not increase in response to growth in low P. However, shoot APase activity was higher in pho3 than in the wild-type plants. In addition, the pho3 mutant had a P-deficient phenotype, even when grown in P-sufficient conditions. The total P content of 11-d-old pho3 plants, grown in agar media with a plentiful supply of P, was about 25% lower than the wild-type level in the shoot, and about 65% lower in the roots. In the rosette leaves of mature soil-grown pho3 plants the total P content was again reduced, to about 50% of wild-type levels. pho3 exhibited a number of characteristics normally associated with low-P stress, including severely reduced growth, increased anthocyanin content (at least 100-fold greater than the wild type in soil-grown plants) and starch accumulation. The results suggest that the mutant is unable to respond to low internal P levels, and may lack a transporter or a signalling component involved in regulating P nutrition.

Growth and nutrition of nonmycorrhizal and mycorrhizal pitch pine (Pinus rigida) seedlings under phosphorus limitation.

The association of ectomycorrhizal fungi with tree roots enhances the acquisition of phosphorus (P) from the soil. In addition to increasing the uptake of H(2)PO(4) (-) (P(i)), mycorrhizal fungi may increase the spectrum of P sources utilized by tree roots by mediating the dissolution of insoluble metallophosphate salts or the hydrolysis of organic P compounds. To investigate the role of ectomycorrhizal fungi in enhancing P acquisition by tree roots, pitch pine (Pinus rigida Mill.) seedlings were grown in sand culture with or without the ectomycorrhizal symbiont Pisolithus tinctorius Coker and Couch under various conditions of P limitation. Compared with nonmycorrhizal seedlings, seedlings inoculated with P. tinctorius exhibited a greater capacity to function under P limitation as evidenced by superior growth and the maintenance of normal foliar ion composition at low P(i) concentrations. Nonmycorrhizal seedlings subjected to P-limiting conditions exhibited depressed K and P and elevated Na concentrations in foliage. The association of P. tinctorius with pitch pine seedling roots maintained foliar K concentrations and prevented the accumulation of Na under P limitation. Nonmycorrhizal seedlings were unable to obtain P from either solid AlPO(4) or inositol hexaphosphate (IHP), whereas seedlings inoculated with P. tinctorius utilized AlPO(4), but not IHP as a P source. Root surface acid phosphatase (APase) activity was depressed in roots infected with the mycorrhizal symbiont and was negatively correlated with seedling growth on all P sources. Root APase activity was negatively correlated with foliar P concentrations in seedlings grown on P(i), but was not correlated with foliar P concentrations in seedlings cultured with AlPO(4) or IHP.

Phosphorus assimilation i mycorrhizal moong ( Vigna radiata L.) plants under different phosphorus levels

Influence of phosphorus on its assimilation was studied in a pot experiment at two growth stages at different phosphorous (P) levels control (P 0), 10 μg P g −1 soil (P 10) and 20 μg P g −1 soil (P 20) in non-mycorrhizal (NM) and mycorrhizal (M) moong plants. The response of M plants to P application varied both with growth stage and P level. In NM plants, total P, shoot fresh weight (FW) and exopoly-phosphatase (ExoPase) activity in roots was enhanced with both P levels while root peroxidase and acid phosphatase activities (APase) in leaves increased with P 20 level only. Ester P, root FW, inorganic phosphate (P i) and APase activity in roots were not affected at P 10 level. Total P and P i in leaves were enhanced with MP 10 but were unaltered with MP 20 treatment at 38 days after sowing (DAS). ExoPase and peroxidase activities increased but total P in leaves decreased with MP 10 and MP 20 plants at 50 DAS. APase activity and ester P in leaves increased with MP 20 while Chl concentration decreased at 38 as well as 50 DAS. Soil available P increased with both levels in M plants but only with P 20 with NM plants. The comparison of M and NM plants showed that M plants had greater P i at both samplings whereas root total P and Chl only at 50 DAS at each P level. Shoot FW and root ExoPase activity were greater in M plants with P 0 and P 10 levels. NM plants accumulated ester P more in roots while M plants in leaves at 50 DAS.