High Inorganic Phosphorus Research Articles

Necrotic lower extremities ulcers caused by calciphylaxis in chronic renal failure patient

Introduction: Lower extremity ulcers often create diagnostic challenges and influence patient morbidity and mortality. The most common causes are venous insufficiency, arterial insufficiency, and neuropathic. Ulcers associated with systemic condition often face diagnostic and therapeutic challenge. We report a necrotic lower extremity ulcer caused by calciphylaxis in a patient with chronic renal failure.
 Case: We reported a 48-year-old Javanese woman, complained of painful lower extremities ulcers since 1.5 months ago. The patient had a history of renal failure and hypertension, undergone routine hemodialysis since 13 years ago, and used Continuous Ambulatory Peritoneal Dialysis (CAPD) since one year ago. Dermatology status on dorsum pedis sinister as well as cruris dexter and sinister showed multiple ulcers on livid skin covered by black eschar, accompanied by tenderness. Laboratory results showed anemia (Hb 7.6), hypoalbuminemia (2.7), increased serum urea level (170.4 mg/dl), increased serum creatinine (11.23 mg/dl), increased calcium (10.4 mg/dl), high inorganic phosphorus (8.5 mg/dl) and high parathyroid hormone (2,164). BOF examination showed abdominal calcification, while radiographic examination on cruris dexter et sinister showed soft tissue calcification and osteoporosis. Histopathology result supported the presence of calciphylaxis. The patient was diagnosed with stage V chronic renal failure, hypertension, and calciphylaxis caused by secondary hyperparathyroidism. She was managed by low calcium and phosphate diet, lanthanum, paracetamol, folic acid, adalat oros, captopril and wound debridement.
 Conclusion: Calciphylaxis is rare phenomenon of cutaneous necrosis associated with end-stage renal disease. Control of end-stage renal disease may be an important factor for treatment of calciphylaxis and patient with calciphylaxis usually had a poor prognosis.

Characteristics and Quality of Japanese Traditional Fermented Soybean (Natto) from a Low-phytate Line.

The Japanese traditional fermented soybean or "natto", a cheap and nutrient-rich food, is very popular in Japan. The low-phytate (LP) soybeans exhibit higher mineral bioavailability; however, their use in preparing natto has not been reported. Therefore, in this study, characteristics and quality of natto prepared using LP soybean were investigated. The findings revealed a better color, lower stickiness, and lower hardness and taste of LP natto with lower phytate and higher inorganic phosphorus (Pi) concentrations than those in the normal-phytate (NP) natto. However, the Ca, Mg, and K concentrations were not significantly different between LP and NP natto, whereas the protein level in NP natto was slightly higher than that in LP natto. These findings indicate that the lower phytate content in LP natto than that in NP natto, could facilitate a higher bioavailability of P and other minerals. Moreover, the improved color and lower stickiness, in addition to lower hardness and taste of LP natto, imparted through improved manufacturing process could increase its acceptability overseas, thereby increasing its commercial value. These improved qualities of LP natto could contribute to improving human health as well as increasing sustainable food and nutrient security.

Differential response of rhizoplane, rhizosphere and water wetland bacterial communities to short-term phosphorus loading in lab scale mesocosms

The effects of water quality on wetland-associated bacterial communities exposed to high inorganic phosphorus (P) concentrations by studying rhizoplane, rhizosphere and water microbial communities were examined using mesocosms planted with either Phalaris arundinacea or Veronica anagallis-aquatica. Mesocosms were exposed to high or poor water quality treatments for 91 days before receiving a 5 mg/L pulse of P (P2O5), and were sampled until 49 days after exposure (DAE). Structural community characteristics were determined using PCR-DGGE banding patterns from 16S bacterial DNA. Functional changes were assessed from carbon source utilization profiles (Biolog™ Ecoplates). Microbial communities differed in their response to P loading. Rhizoplane communities showed the most significant changes to structural and functional characteristics, while rhizosphere communities exhibited the least. A combination of factors including water quality and plant species influenced rhizoplane community structure post-P loading (repeated-measures REML P ≤ 0.05), while structural and functional diversity declined significantly, independent of the treatment (P ≤ 0.001). The results of this study indicate that environmentally relevant levels of inorganic P can have significant effects on wetland-associated microbial communities, however, these effects are dependent on the bacterial community being monitored. Water quality and plant species may play a secondary role in determining these effects.

Resolving the paradox: Continuous cell-free alkaline phosphatase activity despite high phosphate concentrations

It is generally recognised that enzymatic activities are controlled by their end-product concentration, so that when the end-product concentration is high the enzyme activity is low and vice versa. In the marine environment, however, high alkaline phosphatase (APase) activities at high inorganic phosphorus (Pi) concentrations are commonly observed. This represents a paradox that has been unresolved for decades. This study builds on recent advances in the understanding of the role of cell-free versus cell-associated extracellular enzymatic activities (EEAs) to find an explanation for this long-time enigma. Data was collected from coastal (biweekly for 1 y), epi- and mesopelagic waters open-ocean (bimonthly for 9 months) and lab experiments to investigate the relation between APase (cell-free and cell-associated) and Pi. The proportion of cell-free APase was consistently high across all these marine environments (ranging from 65 to 100% of the total activity), irrespective of the Pi concentration. A residence times experiment performed with APase enzymes from the same marine environment confirmed that cell-free APase maintained most of its activity (ca. 75% of the initial in situ activity) over a 16-day incubation. This demonstrates the long lifetime of APase in the marine environment, and the potential for spatial and temporal decoupling between the Pi concentrations and the total APase activity. Collectively, these results together with previous evidence, suggest that the persistent presence of cell-free APase activity provides a reasonable explanation for the paradox of high potential APase activities at high end-product (Pi) concentration in the marine environment. Ultimately, this finding also serves as an example of the potential critical role that cell-free enzymes play in the ecology and biogeochemistry of the ocean.

Necrotic lower extremities ulcers caused by calciphylaxis in chronic renal failure patient

Introduction: Lower extremity ulcers often create diagnostic challenges and influence patient morbidity and mortality. The most common causes are venous insufficiency, arterial insufficiency, and neuropathic. Ulcers associated with systemic condition often face diagnostic and therapeutic challenge. We report a necrotic lower extremity ulcer caused by calciphylaxis in a patient with chronic renal failure. Case: We reported a 48-year-old Javanese woman, complained of painful lower extremities ulcers since 1.5 months ago. The patient had a history of renal failure and hypertension, undergone routine hemodialysis since 13 years ago, and used Continuous Ambulatory Peritoneal Dialysis (CAPD) since one year ago. Dermatology status on dorsum pedis sinister as well as cruris dexter and sinister showed multiple ulcers on livid skin covered by black eschar, accompanied by tenderness. Laboratory results showed anemia (Hb 7.6), hypoalbuminemia (2.7), increased serum urea level (170.4 mg/dl), increased serum creatinine (11.23 mg/dl), increased calcium (10.4 mg/dl), high inorganic phosphorus (8.5 mg/dl) and high parathyroid hormone (2,164). BOF examination showed abdominal calcification, while radiographic examination on cruris dexter et sinister showed soft tissue calcification and osteoporosis. Histopathology result supported the presence of calciphylaxis. The patient was diagnosed with stage V chronic renal failure, hypertension, and calciphylaxis caused by secondary hyperparathyroidism. She was managed by low calcium and phosphate diet, lanthanum, paracetamol, folic acid, adalat oros, captopril and wound debridement. Conclusion: Calciphylaxis is a rare phenomenon of cutaneous necrosis associated with end-stage renal disease. Control of end-stage renal disease may be an important factor for treatment of calciphylaxis and patient with calciphylaxis usually had a poor prognosis.Keywords: necrotic lower extremity ulcer, chronic renal failure, calciphylaxis

Biochemical profiling and its role in physiological quality of maize seeds

Abstract: Viability and vigor of seeds are physiological attributes influenced by a myriad of factors including the genotype. Biochemical profiling of maize seeds and its correlation with their physiological quality is of crucial importance in breeding programs that the aim is seeds of better quality. The main goal of this study was to analyze the genetic diversity among maize inbred lines and evaluate the biochemical components that have an important role in physiological quality of seeds. The seeds of the inbred lines and hybrids were submitted to viability test, vigor by the accelerated aging and cold tolerance, and biochemical profiling (total protein content, soluble proteins, total phosphorus, phytate, inorganic phosphorus, starch and soluble sugars). The genetic divergence between the inbred lines found, prompt us to conclude that genetic gains may exist in association with physiological quality of maize hybrids. Seeds with higher inorganic phosphorus and soluble sugars presented superior physiological quality than seeds with lower levels of those compounds.

Dietary intake of inorganic phosphorus has a stronger influence on vascular-endothelium function than organic phosphorus.

Phosphorus management through dietetic therapy is vital for the prevention of cardiovascular disease in chronic kidney disease patients. There are two main sources of phosphorus in the diet, organic phosphorus from protein and inorganic phosphorus from food additives. The adverse effects of high phosphorus intake on vascular-endothelium function have been reported; however, the differences in the effects of organic phosphorus versus inorganic phosphorus are not clear. In this study, we examined an acute effect of these high phosphorus meals intake on vascular-endothelium function. This was a randomized, double-blind, cross-over test study design targeting healthy young men. We conducted a food intake test using two test meals, one high in organic phosphorus from organic food sources, and one high in inorganic phosphorus from food additives. Endothelium-dependent vasodilation, phosphorus and calcium in the urine and blood, and phosphorus-related hormones were measured preprandial to 120 min postprandial. The results showed higher serum and urine phosphorus values after the high inorganic phosphorus meal, and a significant reduction in endothelium-dependent vasodilation at 30 min postprandial. These findings are evidence that inorganic phosphorus has a stronger influence on vascular-endothelium function than organic phosphorus.

Selection efficiency of high inorganic phosphorus-low stachyose lines from soybean breeding populations of different genetic backgrounds

ABSTRACTReducing the antinutritional components of soybean (Glycine max) seed is necessary for producing animal feed with increased metabolizable energy and nutrient availability. The objective of this study was to evaluate marker-assisted and phenotypic selection for the high inorganic phosphorus (Pi) and low stachyose traits controlled by the Lpa and MIPS1 mutations in six breeding populations. Phenotypic selection for low phytate individuals carrying Lpa mutations using Pi was reliable, but the assay should include parental genotypes to construct thresholds before performing selections, as the effect of Lpa on Pi depends on genetic background. Phenotypic selection for low phytate individuals carrying MIPS1 using Pi should be complemented with sugar data because selection based solely on Pi may be inefficient, as this trait is not environmentally stable in MIPS1 germplasm. Marker-assisted selection for simple sequence repeat (SSR) linked to Lpa2 (Satt527, Satt561) depended on the pedigree of the population suggesting that perfect markers (e.g., single nucleotide polymorphism) should become the molecular tool for screening a large number of progenies with high efficiency.

Registration of ‘Harriman’ Low‐Phytate, Hulled Spring Barley

‘Harriman’ (Reg. No. CV‐358, PI 676261) is a hulled, low‐phytate barley (Hordeum vulgare L.) cultivar, the second to be developed and released by the USDA‐ARS. Compared to the previously released hulled, low‐phytate cultivar, ‘Herald’, Harriman has higher grain yield, higher test weight, higher inorganic phosphorus (Pi), and lower phytate phosphorus (P). This cultivar can contribute to animal production and sustainable agriculture by reducing or eliminating the need for P or phytase supplementation and by reducing the amount of P released into the environment from animal production facilities.

A value based approach to determine optimal phytase dose: A case study in turkey poults

There is a recent trend to increase phytase dose from the traditional 500FTU/kg to 750 or 1000FTU/kg in poultry feed formulations, driven by high inorganic phosphorus prices and more bioefficacious phytases. This paper outlines a method for calculating optimum phytase dose, based on the replacement of inorganic phosphorus through the application of the marginal decision rule. In this 21day digestibility study 768 male BUT 6 turkey poults were assigned to 8 treatments (6 replications/treatment): a negative control diet based on corn/soy, meeting the nutritional requirements of turkey poults except in phosphorus (0.26% ret P) and calcium (0.8%), 4 graded levels of phytase over the negative control (345, 690, 1035, 1380FTU/kg), and 3 graded levels of supplemental MCP (0.6, 1.2, 1.8g P/kg). Significance was determined using ANOVA and means separation for all parameters was achieved using Tukey’s HSD. Bodyweight gain was maximised at the 1035FTU/kg dose, with all levels of phytase supplementations significantly increasing BWG compared to the negative control (P<0.05). Non-linear regression was conducted on ileal phosphorus digestibility, and optimum phytase dose was determined using the as the point where the incremental value of P release was equal to the incremental phytase cost, assuming the value of incremental P from phytase was equal to the value of the same amount of digestible P from an inorganic source. The optimum dose of phytase under typical 2014 US market price conditions was calculated to be 996FTU/kg. At 996FTU/kg, 100% of the potential value of inorganic P replacement was captured, compared to 70% of the value at 500FTU/kg. Under different phytase and inorganic P price conditions, the optimum dose varied between 762FTU/kg and 1231FTU/kg. In conclusion, this study highlights a method that provides a rational justification for use of targeted phytase doses greater than 500FTU/kg.

Involvement of Ethylene in the Latex Metabolism and Tapping Panel Dryness of Hevea brasiliensis.

Ethephon, an ethylene releaser, is used to stimulate latex production in Hevea brasiliensis. Ethylene induces many functions in latex cells including the production of reactive oxygen species (ROS). The accumulation of ROS is responsible for the coagulation of rubber particles in latex cells, resulting in the partial or complete stoppage of latex flow. This study set out to assess biochemical and histological changes as well as changes in gene expression in latex and phloem tissues from trees grown under various harvesting systems. The Tapping Panel Dryness (TPD) susceptibility of Hevea clones was found to be related to some biochemical parameters, such as low sucrose and high inorganic phosphorus contents. A high tapping frequency and ethephon stimulation induced early TPD occurrence in a high latex metabolism clone and late occurrence in a low latex metabolism clone. TPD-affected trees had smaller number of laticifer vessels compared to healthy trees, suggesting a modification of cambial activity. The differential transcript abundance was observed for twenty-seven candidate genes related to TPD occurrence in latex and phloem tissues for ROS-scavenging, ethylene biosynthesis and signalling genes. The predicted function for some Ethylene Response Factor genes suggested that these candidate genes should play an important role in regulating susceptibility to TPD.

Species and Biogeochemical Cycles of Organic Phosphorus in Sediments From a River With Different Aquatic Plants Located in Huaihe River Watershed, China

The results of phosphorus fractionation in the sediments from a contaminated river containing different aquatic plants, analyzed by solution 31P-NMR for Organic Phosphorus, showed that the concentration of Inorganic Phosphorus dominated in all species and Organic Phosphorus accounted for over 20% of Total Phosphorus. In general, orthophosphate was dominant in all the sampling sites. The proportion of Organic Phosphorus accounting for the Total Phosphorus in the sediments with different plant decreased in the following order: Paspalum distichum > Typha orientalis > Hydrilla verticillata. Phosphorus-accumulation ability of Paspalum distichum was obviously stronger than Typha orientalis and Hydrilla verticillata. The Organic Phosphorus was in aquatic plants dominated by humic-associated P (Hu-P), which converted to Inorganic Ohosphorus more significantly in submerged plants than in emerged plants. The sediment dominated by Paspalum distichum abundantly accumulated Organic Phosphorus in the orthophosphate monoester fraction. The degradation and mineralization of orthophosphate monoester was the important source of high Inorganic Phosphorus concentration and net primary productivity in Suoxu River. The Organic Phosphorus derived from Typha orientalis and Hydrilla verticillata was dramatically converted to Inorganic Phosphorus when the environmental factors varied.

Planting Date and Delayed Harvest Effects on Soybean Seed Composition

ABSTRACTInformation on crop management practices that may help maximize farm profit is valuable. Because planting date determines the environment to which the crop is exposed during the growing season, it can also have a significant impact on seed composition. In this study, the effects of planting date on seed organic and inorganic composition were investigated using eight specialty soybean [Glycine max (L.) Merr.] breeding lines with modified seed composition (high protein, high oil, high oleic acid, low linolenic acid, low saturated fatty acids, high inorganic phosphorus–low stachyose) grown at two Arkansas locations for 2 yr. The effects of delayed harvest on seed composition were also studied in one of the planting dates. Early planting increased seed protein, oleic acid, and inorganic components and decreased linolenic acid concentrations, whereas late planting increased sucrose but did not affect stachyose concentrations. Production of soybeans with high‐protein, high‐quality oil should be performed in early‐planting production systems, whereas planting high‐sugar, food‐grade cultivars late in the season should fit well in a double‐crop system. Delayed harvest had effects on both organic and inorganic seed components. Seed constituents exhibited lower concentration in soybeans that experienced delayed harvest. These research findings may help enhance recommendations to farmers to adjust planting and harvest practices and consequently meet market requirements for specialty soybeans.

Selection of High Inorganic Phosphorus-Low Stachyose Soybean Breeding Lines

Soybean (Glycine max [L.] Merr.) seed stachyose and phytic acid are not digested by monogastric animals, and thus represent an obstacle for an efficient utilization of soybean meal in animal feed. The objectives of this research were to select breeding lines with high inorganic phosphorus (Pi)/low stachyose, along with adequate levels of sucrose, from an F2:6 population derived from the cross S02-529 x V99-5089 and evaluate their yield potential and stability across environments. Sucrose distribution showed no distinctive pattern, whereas Pi and stachyose exhibited a bimodal distribution. Stachyose and Pi fit the expected 3:1 ratio for a one-gene model previously reported for the high-Pi/low-stachyose trait in V99-5089. The highest yielding line, R08-6023 (2894 kg ha−1), showed relatively low stability for yield across environments, but it would be an adequate choice for highly productive environments. R08-6009 (2634 kg ha−1) ranked fourth in yield but showed less yield fluctuations across environments than other lines studied. One selected line had moderately high oleic acid concentration (>45 mg g−1), and three other lines had low linolenic acid concentration (<34 mg g−1), which are unique combinations with the high-Pi/low-stachyose trait. Although relatively low in yield as compared to the commercial checks, these novel breeding lines would be useful in breeding programs in developing multiple-trait stacks of value when incorporated into high-yielding backgrounds.

Idiopathic Hypoparathyroidism Presenting as Adult Onset Seizures

Idiopathic hypoparathyroidism is a rare disorder of unknown etiology. It usually presents by second decade of life but delayed manifestations are known to occur. It presents as neuromuscular excitability, numbness, carpopedal spasm, 1 cramps, laryngeal stridor and convulsions. In subtle cases of hypoparathroidism neuromuscular excitability can be made evident by eliciting Chovstek's and Trousseu's 2 sign. Typical ECG manifestations are QTC prolongation. Cataract, intracranial calcification are well known entities. 3 Various other manifestations are Parkinsonism, Choreo athetosis, Spasm etc. Typically patients have low serum calcium, high inorganic phosphorus with low to undetectable PTH. In all such patients renal failure, chronic GI disorders, persistent alkalosis, rickets and osteomalacia should be excluded. JMS 2012;15(2):182-83

English

&nbsp; In last decades, large area of dry-farming field has been converted to paddy field in the Sanjiang Plain of the Northeastern China. It is assumed that this land-use change might impact the level, chemical forms, and availability of phosphorus in the soils. Five soil cores were collected separately in the paddy field and dry-farming field and were analyzed for pH, soil organic matter (OM), aluminium (Al), iron (Fe), calcium (Ca), potassium (K), total phosphorus (TP), and phosphorus forms. The topsoil of the paddy filed contained lower OM, Fe, Al, organic phosphorus (Por), and residual phosphorus and higher inorganic phosphorus (Pinor) and iron oxides-bound phosphorus (Fe-P) than that of the dry-farming field. However, TP and plant-available phosphorus (AP) levels were generally not affected by the land-use change. The bulk of soil phosphorus mainly exists in Por, Fe and Al-bounded phosphorus, and Ca-bound phosphorus, while AP was significantly correlated to Pinor, Al-bound phosphorus (Al-P), and Fe-P but not correlated to Por in the both fields. Therefore, the conversion of dry-farming field to paddy field did not impact TP and AP levels, but changed the phosphorus forms in the albic black topsoil, with increase of Pinor and iron oxides-bound P and decrease of Por. &nbsp; Key words: Phosphorus fractionation, paddy field, dry-farming, plant available phosphorus.

Phosphorus nutrition of ectomycorrhizal Gnetum africanum plantlets from Cameroon

A study was carried out to evaluate the effect of mycorrhization on the growth and P uptake of Gnetum africanum rooted cuttings at low and high inorganic phosphorus availability. Gnetum rooted cuttings were grown in a peat/sand 50:50 mix to enable the development of fine roots. Nutrient evaluation was carried out in sand/peat 10:1 mix (NIL), mix amended with 30 mg/kg P (I), mix amended with 300 mg/kg P (II). Generally ectomycorrhizal plants showed better growth than non-mycorrhizal plants. The number of new EM tips formed decreased with an increase in P level. Ectomycorrhization led to an increase in shoot dry weight, number of leaves and shoot elongation. Ectomycorrhization of Gnetum also resulted to increased access to added P whilst the effect on N uptake was greatest when P was added. The results showed that Gnetum responds positively to mycorrhization and that the response may not be solely attributed to increased uptake of nutrients including P and N. From this observation it is certain that in the domestication of Gnetum, mycorrhization alone would not be enough but that a combination of mycorrhization and nutrient addition would be necessary for the successful establishment and growth of the plant.

Mutational approach for N2-fixing and P-solubilizing mutant strains of Klebsiella pneumoniae RSN19 by microwave mutagenesis.

Nitrogen (N) fixing Klebsiella pneumoniae RSN19 has high inorganic phosphorus (P) solubilizing capability, but its N2-fixing capability is limited. In order to acquire a P-solubilizing mutant strain with high efficiency N-fixing capability, different microwave irradiation intensities and durations were tested on RSN19 in an attempt to produce mutants with improved N2-fixation and P-solubilization capabilities. The effect of microwave irradiation power and time were studied and the microwave mutagenesis parameters were optimized. Nitrogenase activity was tested on the mutant strains by acetylene reduction method; and their P-solubilizing capability and genetic stability were determined. The results indicated that the best conditions for microwave mutagenesis that produced better performed mutant strains were 250W, 36s. Under these conditions a maximum positive mutation rate of 1.66% was obtained, resulting in five genetically stable strains with promoted nitrogenase activity which was designated as RSM-219, RSM-206, RSM-224, RSM-225 and RSM-275. Subculture tests showed that RSM-219 and RSM-206 were genetically stable mutant strains with higher nitrogenase activity and phosphate solubilizing capabilities than the original strain. Both RSM-219 and RSM-206 performed better than the original strain under N-free conditions when supplied with calcium phosphate only, and produced greater increases in the biomass of alfalfa seedlings.

Water quality assessment and meta model development in Melen watershed – Turkey

Istanbul, being one of the highly populated metropolitan areas of the world, has been facing water scarcity since the past decade. Water transfer from Melen Watershed was considered as the most feasible option to supply water to Istanbul due to its high water potential and relatively less degraded water quality. This study consists of two parts. In the first part, water quality data covering 26 parameters from 5 monitoring stations were analyzed and assessed due to the requirements of the “Quality Required of Surface Water Intended for the Abstraction of Drinking Water” regulation. In the second part, a one-dimensional stream water quality model with simple water quality kinetics was developed. It formed a basic design for more advanced water quality models for the watershed. The reason for assessing the water quality data and developing a model was to provide information for decision making on preliminary actions to prevent any further deterioration of existing water quality. According to the water quality assessment at the water abstraction point, Melen River has relatively poor water quality with regard to NH 4 +, BOD 5, faecal streptococcus, manganese and phenol parameters, and is unsuitable for drinking water abstraction in terms of COD, PO 4 3−, total coliform, total suspended solids, mercury and total chromium parameters. The results derived from the model were found to be consistent with the water quality assessment. It also showed that relatively high inorganic nitrogen and phosphorus concentrations along the streams are related to diffuse nutrient loads that should be managed together with municipal and industrial wastewaters.

Long-term effect of ethylene stimulation on the yield of rubber trees is linked to latex cell biochemistry

Ethylene stimulation with ethephon (2-chloroethylphosphonic acid) is nowadays essential for increasing latex production in the rubber tree ( Hevea brasiliensis): both small-scale planters and agro-industrial plantations worldwide use ethephon. Ethylene stimulation strongly influences cumulative yield and latex cell biochemistry. The purpose of this study was to characterize the long-term behaviour of the rubber tree under ethephon treatment. Over a period of 7 years in Côte d’Ivoire, West Africa, the effect of eight frequencies of ethylene stimulation on yield and latex cell biochemistry was compared in four rubber trees clones, IRCA 130, IRCA 230, GT 1, and PB 217. The ability of the trees to produce more latex under ethylene stimulation was related to the sucrose and inorganic phosphorus contents of the latex cells. For high-yield clones with low sugar content and high inorganic phosphorus content like IRCA 130, namely quick starter clones, no stimulation was necessary to improve yield. For clones like IRCA 230, with higher sugar content, eight ethylene stimulations per year was the optimum frequency to obtain the highest yield. The effect of ethylene stimulation on latex yield increase was significant in clones with high sucrose content and low inorganic phosphorus content such as PB 217. These clones, namely slow starter clones, needed more stimulation to produce more, but in the longer run there were no negative effects of ethylene on the latex yield. These results will help planters optimize latex production by choosing the most appropriate ethylene stimulation to clones according to their latex cells biochemistry.