scholarly journals Relationships of Gibberellic Acid to Water and Phosphorus in the Growth, Sugar Production, and Enzyme Behavior of Sugarcane

1969 ◽  
Vol 53 (3) ◽  
pp. 149-166
Author(s):  
Alex G. Alexander

Immature sugarcane was subjected to variable water and phosphorus (P) supply and then treated with foliar gibberellic acid (GA). All plants were grown in sand culture and received initial water and P treatments at 88 days of age. Water regimes of inadequate, adequate, and abundant supply were established with 1, 2, and 4 liters of water per day, respectively. Variable P included 0, 6, and 30 meq./liter. Foliar GA was given as 0-, 0.01-, and 0.10-percent solutions. There were three objectives: 1 To determine the effectiveness of GA as a growth stimulant and regulator of sugar-enzyme relationships under conditions of water and P stress; 2, to explore physiological limits within which GA-enzyme relationships persist; and 3, to explore the enzyme basis of water and P performance under extreme conditions of GA-stimulated growth. The following results were recorded: 1. Both water and GA had greatly increased stalk weight and intemode length 5 weeks after GA treatment. 2. Water supply strongly affected GA-growth responses. Water-deficient plants were proportionately more stimulated by GA than water-rich plants. However, maximum growth required both GA and abundant water. 3. GA appeared to increase the efficiency of water utilization, regardless of the amount of water supplied. 4. Variable water supply severely transformed the behavior patterns of ATP-ase, amylase, invertase and polyphenol oxidase. 5. GA treatment of low-water plants appeared to increase the severity of water shortage. Hydrolytic enzymes were severely retarded by GA when water supply was low, but not when adequate or abundant water was available. On the basis of growth and enzyme data it was proposed that GA caused an internal redeployment of water so that the net quantity available for enzymatic functions was reduced. It was also proposed that GA might decrease the internal water supply while increasing growth, in contrast to the commercial practice of externally withholding water which decreases growth. 6. Low P was inadequate for maximum growth, but severe P deficiency was not achieved. GA was proportionally more effective in promoting fresh weights and internode elongation when P supply was low. 7. GA moderately increased leaf P content when P supply was low. The increase was primarily organic P (PO) and this was attributed to GA suppression of phosphatase and ATP-ase. The significance of GA alteration of PO is discussed. 8. Evidence was found of a GA-induced PO decline mediated by increased amylase activity. 9. Leaf peroxidase was extremely sensitive to P supply, and to GA in P-hungry plants. The enzyme was excessively active in low-P X low-GA plants. 10. It is shown that cane growth and enzymology is far more sensitive to P than field experiments have indicated. The importance of PO, phosphatases and phosphorylase, as contrasted to total P content, is stressed.

2019 ◽  
Vol 124 (6) ◽  
pp. 961-968 ◽  
Author(s):  
Florian Klamer ◽  
Florian Vogel ◽  
Xuelian Li ◽  
Hinrich Bremer ◽  
Günter Neumann ◽  
...  

Abstract Background and Aims Root hairs are single-cell extensions of the epidermis that face into the soil and increase the root–soil contact surface. Root hairs enlarge the rhizosphere radially and are very important for taking up water and sparingly soluble nutrients, such as the poorly soil-mobile phosphate. In order to quantify the importance of root hairs for maize, a mutant and the corresponding wild type were compared. Methods The rth2 maize mutant with very short root hairs was assayed for growth and phosphorus (P) acquisition in a slightly alkaline soil with low P and limited water supply in the absence of mycorrhization and with ample P supply. Key Results Root and shoot growth was additively impaired under P deficiency and drought. Internal P concentrations declined with reduced water and P supply, whereas micronutrients (iron, zinc) were little affected. The very short root hairs in rth2 did not affect internal P concentrations, but the P content of juvenile plants was halved under combined stress. The rth2 plants had more fine roots and increased specific root length, but P mobilization traits (root organic carbon and phosphatase exudation) differed little. Conclusions The results confirm the importance of root hairs for maize P uptake and content, but not for internal P concentrations. Furthermore, the performance of root hair mutants may be biased by secondary effects, such as altered root growth.


2005 ◽  
Vol 32 (2) ◽  
pp. 153 ◽  
Author(s):  
Madeleine Wouterlood ◽  
Hans Lambers ◽  
Erik J. Veneklaas

Two experiments were conducted to investigate whether carboxylate exudation by chickpea (Cicer arietinum L.) is a response to phosphorus (P) deficiency or a constitutive trait. The effect of P supply on carboxylate concentrations in the plant and in the rhizosphere of chickpea cultivar Heera was studied in a sand culture. Plants were grown in pots supplied with 200 mL of solution containing 0–500 μm P every 3 d. Malonate was the main carboxylate exuded, and the main carboxylate in roots; shoots contained mainly citrate and malate. Contrary to what has been reported for other species, carboxylate concentrations in the rhizosphere decreased only slightly at high P supply, but they were still substantial. The effect of P supply on the rate of exudation was studied in a split-root sand culture. Root systems were split into two pots, one root half received no P and the other half received 200 mL of solution containing 0–500 μm P. The rhizosphere of both root halves contained similar concentrations of carboxylates, even when the plants received a different supply of P. Our results indicate that carboxylate exudation is determined by internal P rather than external factors. The fact that chickpea roots always exude carboxylates indicates that exudation in this species is largely constitutive.


1989 ◽  
Vol 29 (6) ◽  
pp. 861 ◽  
Author(s):  
A Pinkerton ◽  
K Spencer ◽  
AG Govaars

Phosphorus (P) concentrations in young plants of rapeseed (Brassica napus cv. Wesway) were related to seed and oil yields to develop a tissue test for the diagnosis of P deficiency. Critical P concentrations were defined as those concentrations required to sustain 90% of maximum yield. In 2 field experiments in successive seasons on a P-deficient soil, rates of triple superphosphate from 2.5 to 120 kg/ha were banded with the seed. The lowest P concentration in young shoots (17-19 weeks from sowing) associated with a P supply that was adequate for plant growth was approximately 0.31%. The youngest fully-expanded leaf was a reliable plant part to sample, its P concentration being about 0.05% lower than the concentration of the whole shoot. Critical P concentrations in young plants for sustaining 90% of maximum seed and oil yields were higher, namely 0.33 and 0.28% for whole shoots and youngest fully-expanded leaves respectively. The critical P concentration in seeds was about 0.35%.


1969 ◽  
Vol 56 (2) ◽  
pp. 134-153
Author(s):  
Rafael Montalvo-Zapata ◽  
Alex G. Alexander

Immature sugarcane was given variable-water regimes in sand culture and subsequently treated with a powerful desiccant, the bipyridylium herbicide Paraquat, applied as a 0.05-percent aqueous foliar spray. There were two objectives: (a) To evaluate the effects of water regime on sucroseenzyme relationships in desiccating sugarcane; and (b) to determine whether controlled water regimes could effectively modify Paraquat activity in sugarcane. Tissue samples were harvested for moisture, sugar and enzyme analyses at 1,3 and 9 days after Paraquat application. Low water supply (1 liter per day) reduced total fresh weights and stalk weights, and increased sucrose content of immature storage tissue. Paraquat significantly lowered total fresh weights, stalk weights, sheath moisture and leaf sucrose by the 9-day harvest. Desiccant action was generally more rapid within the low-water regime. High- and intermediate-water regimes tended to modify Paraquat activity at 1 or 3 days, but its ultimate effects were comparable regardless of water regime. No evidence was found to support the theory that desiccating cane accumulates water as a function of continued water absorption when transpiration has ceased. Acid invertase was suppressed by Paraquat, an effect consistent with earlier findings. The suppression was most severe in the low-water regime. Low-water supply significantly lowered invertase level but the response was not consistent at all harvests. Acid phosphatase and ATP-ase were severely repressed by Paraquat in leaves but not in immature storage tissue. An explanation was offered in terms of distinct chloroplast and mitochondrial enzymes rather than localized Paraquat action. For both enzymes the desiccant repression was significantly more severe in the high-water regime at 1 or 3 days, but water regime showed no effect at 9 days. Paraquat significantly increased ß-amylase in leaves (consistent with earlier studies), particularly within the high-water regime. In immature stem tissue ß-amylase was repressed by high water in Paraquat-free plants. Paraquat eliminated the water effect. Peroxidase was increased in storage tissue by Paraquat. This response was statistically significant only under conditions of low-water supply. It is concluded that variable water regimes can modify the rate of initial Paraquat activity in sugarcane; however, the ultimate effects of Paraquat will not be changed under conditions of thorough chemical application. Under field conditions of marginal chemical penetration, the plant's moisture status might play a more decisive role in determining the desiccant's effectiveness.


1994 ◽  
Vol 34 (3) ◽  
pp. 373 ◽  
Author(s):  
A Pinkerton ◽  
PJ Randall

Critical phosphorus (P) values, both total (P,) and inorganic Pi, for the diagnosis of P deficiency were derived for a number of pasture species that are increasingly used in Australia. Trifolium balansae and Medicago murex, with T. subterraneum for comparison, were grown for 2 seasons in field experiments to which 7 rates of phosphate fertiliser were applied. The legumes T. balansae, M. murex, M. polymorpha, Ornithopus compressus, and Lotus pedunculatus, and the grasses Phalaris aquatica and Danthonia richardsonii, were grown in sand culture in glasshouse experiments and provided with nutrient solutions containing 6 rates of P (0.05-1.6 mmol/L). Diagnostic indices were derived for blades of the youngest open leaves (YOL) or youngest expanded blades, and for whole shoots. Critical Pt concentration in the YOL of T. balansae did not decline until full flowering and was the most stable indicator. The range of critical concentrations was 0.45-0.50% for both diagnosis of deficiency and prediction of seasonal yield. A Pi concentration of 150 mg/kg was critical for T. balansae during vegetative growth only. Critical concentrations in M. murex declined from an early stage, but a Pt concentration in YOL of 0.40% was the most useful indicator for diagnosis until flowering. The critical values for T. subterraneum agreed well with previously published data. Critical P concentrations in O. compressus were similar at 2 sampling times. For the remaining species, critical concentrations declined with time and it was necessary to know plant age when interpreting them.


2011 ◽  
Vol 41 (2) ◽  
pp. 228-234 ◽  
Author(s):  
Pengfei Wu ◽  
Xiangqing Ma ◽  
Mulualem Tigabu ◽  
Chen Wang ◽  
Aiqin Liu ◽  
...  

Available P is the major growth-limiting factor in southern China where Chinese fir ( Cunninghamia lanceolata (Lamb.) Hook.) plantations are increasingly established. Planting P-efficient clones is a viable option to enhance productivity of Chinese fir plantations. Two Chinese fir clones with high P efficiency (M1 and M4) were chosen as the research materials and their adaptive responses to low P stress were examined. The increment in root morphological traits and biomass production of these clones was measured by a sand culture experiment with a heterogeneous P supply. For both clones, P starvation resulted in significantly higher root surface area and root volume but not root length. For clone M4, the mean root diameter was also larger under P deficiency than under normal P supply. Interestingly, the root morphological traits varied substantially within the same root system where the starved roots had higher values for all morphological traits than the nonstarved ones. Phosphorus starvation did not affect shoot and root biomass or the root to shoot ratio, but the whole-plant biomass increment was large under P deficiency for clone M4. In conclusion, the adaptation to low P stress in these clones is attributed to increased P acquisition and utilization efficiencies.


2003 ◽  
pp. 7-14
Author(s):  
Bettina Eichler ◽  
Adolf Grüner ◽  
Imre Vágó

The P uptakes of 11 different catch crops on four soils were estimated and compared with changes of double lactate soluble Phosphorus (P(DL)) in soil within a vessel trial. Additionally a model trial with quartz sand was carried out for investigations of the influence of P supply on root parameters. The differences of P uptake in dependence of the proofed variants were significant. Under a sufficient P supply Buckwheat, Maize and Oil radish had the highest P uptake on sandy soils, on loamy soil also Buckwheat and Maize but Serradella too. Under P deficiency the withdrawals of Phosphorus for Buckwheat, Maize and Oil radish were found to be the highest. In contrast to the sandy soils for the loamy soils no significant relation between the P uptake by plants and changes in the P-DL amount in soil could be found. For all variants the P uptake by plants were higher than the reduction of the P-DL amount in soil. The rate of P-DL content on the total P content in soil reduced while the two trial years only in sandy but not in loamy soils. The P uptake, the root length and the root/shoot relationship depends significantly on the cultivated crop and the added P compound. The added water soluble KH2PO4 caused a higher P uptake but a lower root/shoot-relationship than the water insoluble P compounds.


2020 ◽  
Vol 19 ◽  
pp. 14
Author(s):  
BIANCA BRAZ MATTOS ◽  
IVANILDO EVÓDIO MARRIEL ◽  
SYLVIA MORAIS DE SOUSA ◽  
UBIRACI GOMES DE PAULA LANA ◽  
ROBERT EUGENE SCHAFFERT ◽  
...  

Sorghum bicolor adapts to phosphorus (P) deficient soils through mechanisms that contribute to its absorption and solubilization, including the association with microorganisms. The direct application of rock phosphate (RP) and the inoculation with phosphate solubilizing bacteria (PSB) is a sustainable alternative for P supply to the crops. The aim of this study was to evaluate the effect of PSB inoculation of two sorghum genotypes with different P responses (BR007 - efficient and responsive and SC283 - efficient and non-responsive), cultivated in soil fertilized with RP and triple superphosphate (TSP), in greenhouse and field experiments. The sorghum genotypes were inoculated separately with the Bacillus strains that are efficient in P solubilization, B116 and B70, and cultivated under different P fertilization sources (TSP, RP, ½TSP + ½RP). The results suggest that the inoculation response was dependent on sorghum genotype, P source and microbial strain. Inoculation of the genotype BR007 significantly increased root biomass and grain P content under greenhouse conditions, as well as yield and grain P content in field experiments, but no effect was observed on genotype SC283. The use of PSB as bioinoculants, in combination with RP, is a promising alternative to reduce the use of synthetic fertilizers, contributing to the sustainable sorghum production.


Author(s):  
R. Comber

AbstractThe Oriental tobacco variety Izmir has been grown in sand culture in a greenhouse under various degrees of water stress. Plants given 400 cm


2021 ◽  
Author(s):  
Xiucheng Liu ◽  
Yuting Wang ◽  
Shuangri Liu ◽  
Miao Liu

Abstract Aims Phosphorus (P) availability and efficiency are especially important for plant growth and productivity. However, the sex-specific P acquisition and utilization strategies of dioecious plant species under different N forms are not clear. Methods This study investigated the responsive mechanisms of dioecious Populus cathayana females and males based on P uptake and allocation to soil P supply under N deficiency, nitrate (NO3 −) and ammonium (NH4 +) supply. Important Findings Females had a greater biomass, root length density (RLD), specific root length (SRL) and shoot P concentration than males under normal P availability with two N supplies. NH4 + supply led to higher total root length, RLD and SRL but lower root tip number than NO3 − supply under normal P supply. Under P deficiency, males showed a smaller root system but greater photosynthetic P availability and higher leaf P remobilization, exhibiting a better capacity to adaptation to P-deficiency than females. Under P deficiency, NO3 − supply increased leaf photosynthesis and PUE but reduced RLD and SRL in females while males had higher leaf P redistribution and photosynthetic PUE than NH4 + supply. Females had a better potentiality to cope with P deficiency under NO3 − supply than NH4 + supply; the contrary was true for males. These results suggest that females may devote to increase in P uptake and shoot P allocation under normal P availability, especially under NO3 − supply, while males adopt more efficient resource use and P remobilization to maximum their tolerance to P-deficiency.


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