Studies in the mineral nutrition of Japanese mint

Summary This paper presents the results of an experimental enquiry into the effects of phosphorus deficiency and age on the nitrogen metabolism in component parts of mint plants (Mentha arvensis var.piperascens).Estimation of various nitrogenous fractions i.e. ammoniacal, nitrate, amide, rest, total soluble, total insoluble and total nitrogen were made in leaf, stem and root of mint plants, collected from full-nutrient and phosphorus-deficient cultures, at subsequent stages of the life cycle. The outstanding effect of phosphorus deficiency was noted: an increased accumulation of amides resulting in poor formation of proteins which suggested interference in protein synthesis beyond amide stage. Leaf showed maximum percentage of nitrogen in the insoluble form. The stem served as channel for transport and storage and invariably showed high concentration of soluble nitrogen fractions.     

Nitrogen metabolism of leaves during growth ofPhaseolus aureus L. as affected by S,P and N application

Summary An application of sulphur (upto 90 ppm) alone or in combination with phosphorus and nitrogen, increased the content of total nitrogen, protein nitrogen and total soluble nitrogen but decreased amide, amino, ammoniacal and nitrate nitrogen and with further increase in dose, all the nitrogen fractions decreased. Higher doses of nitrogen in combination with sulphur increased the content of amide nitrogen and nitrate nitrogen in leaves only at 15 and 30 days stages. Higher doses of phosphorus in combination with sulphur and nitrogen decreased the content of all nitrogen fractions in leaves. All the nitrogen fractions decreased in age except the amide and ammoniacal nitrogen which increased upto 30 days and then started decreasing.     

Changes in physiology and biochemistry of mottle streak virus infected finger millet plants

A significant reduction in the growth parameters viz., plant height, number of tillers, number of productive tillers, leaves, leaf area, 1000 grain weight and grain yield were observed in the mottle streak virus infected finger millet plants compared to healthy finger millet plants. The germination and vigour of seedlings from the seeds of infected plants were reduced. Physiological changes in finger millet as a result of virus infection were investigated. The chlorophyll pigments ‘a’ and ‘b’ as well as total chlorophyll were reduced due to mottle streak infection. The virus infection led to increased total sugar, starch, soluble protein and phenol contents. The mineral metabolism of infected plants showed a reduction in nitrogen, phosphorus, potassium, magnesium, calcium and iron.     

Studies in the mineral nutrition of Japanese mint

Summary The outstanding effects of potassium deficiency on Japanese mint during winter and rainy seasons were marked accumulation of ammonia, amide and nitrate nitrogen with corresponding decrease in protain ntioen indicating arrested protein synthesis at ammonia- and amide formation stages as these fractions showed large proportion in the pool of soluble-N. The accumulation of soluble-nitrogen could be correlated with high respiration rate. Further, potassium-deficient plants had lowe value of rest-N and tootal N in winter and vice a versa in rainy season. In spite of an increased per cent essential oil content (ml/100 g dry weight), the total essential oil production (ml/plant) was low. In general, rainy season plants had higer percentage of essential oil and total oil/plant but showed lower values of all the forms of nitrogen.     

Effect of Phosphorus Deficiency on Carbohydrate Metabolism of Mentha arvensis

The effects of phosphorus deficiency on carbohydrate fractions of Mentha arvensis L. var. piperascens were studied. Mint plants were grown in sand cultures under full nutrition and phosphorus deficiency conditions. Component organs, viz., leaf, stem and root, were sampled at four different stages of the growth cycle and analysed for various sugar fractions. In leaf and root phosphorus deficiency brought about a definite increase in all sugar fractions whereas in stem a reduction was noticed. The stem appeared to be the principal storage organ throughout the growth. Maximum sugar concentration was recorded at the age of 70 days, which represents the full maturity stage, and coincided with maximum essential oil accumulation.     

Studies in the mineral nutrition of Japanese mint

Summary Potassium deficiency resulted in a increased accumulation of total phosphorus, inorganic phosphorus and sugar phosphate which suggested some interference in phosphorus metabolism predominantly beyond the sugar phosphate synthesis stage. Roots appeared to be a reservoir for accumulation of various phosphorus fractions of Japanese mint (Mentha arvensis L. var.piperascens).A higher respiration rate under potassium deficiency might be one of the factors to retard the inclusion of inorganic phosphorus into structural components, resulting in poor formation of organophosphorus compounds needed for plant growth and development. In spite of an increased essential oil content (ml/100 g dry weight) in a phosphorus deficient situation, total essential oil production (ml/plant) was low. Foliage growth, essential oil content and respiration was higher between 60 to 80 days and seemed to be associated with a high intensity of enzymatic and metabolic activity, as observed in various phosphorus fractions rising to a very high value after 80 days of crop growth.     

Alterations in growth and metabolism of potato plants by calcium deficiency

Summary Experiment in water culture was conducted to evaluate the calcium deficiency symptoms and their cause inSolanum tuberosum L. var. Chandramukhi. Meristematic regions at stem and roots were severely affected and ultimately ceased to grow. Plants remained stunted with few and smaller tubers. Reducing sugar, non-reducing sugar and starch accumulated more in the leaves and stems and less in roots and tubers of calcium deficient plants. Deficiency caused decrease in protein nitrogen, RNA, DNA and increase in soluble nitrogen in all the plant parts. Potassium, phosphorus, calcium and sodium contents were lower and magnesium content higher in the deficient plant, than that of the healthy ones. Morphological symptoms of calcium deficiency can be established by ionic balance and accumulation of oxalic acid in potato plants.     

Interactive Effects of Thiourea and Phosphorus on Clusterbean Under Water Stress

Effects of phosphorus and thiourea application (either alone or in combination) were studied on clusterbean (Cyamopsis tetragonoloba Taub.) plants subjected to water stress by withholding irrigation at pre- and post-flowering stages in pot culture trial. Water stress significantly decreased shoot water potential, relative water content of leaves, net photosynthetic rate, contents of total chlorophyll, starch and soluble proteins as well as nitrate reductase activity at both the growth stages. Application of phosphorus and thiourea or combined application increased most of these parameters. Results revealed synergistic effects of P and thiourea in enhancing net photosynthesis, leaf area, chlorophyll content and nitrogen metabolism leading to significant improvement in plant growth and seed yield under water stress condition.     

The winter and summer partitioning of dissolved nitrogen and phosphorus. Observations across the Irish Sea during 1997 and 1998

Winter and summer water column profiles from a transect co-inciding with the 54° N parallel across the Irish Sea were examined for relationships between the fractions of total dissolved nitrogen and phosphorus. Inorganic nitrogen and phosphorus gave the expected seasonal variation. As inorganic nitrogen concentrations decreased during the summer, dissolved organic nitrogen concentrations increased. Dissolved organic phosphorus showed little seasonal variation and formed a smaller fraction of the total dissolved pool compared to nitrogen. Winter inorganic nitrogen and phosphorus salinity relationships were conservative: winter organic nitrogen and phosphorus salinity relationships were not conservative. In the winter, dissolved organic nitrogen and phosphorus formed a significant fraction of the total dissolved pool.     

Effects of calcium deficiency on symbiotic nitrogen fixation

The mechanism of the effect of mild calcium deficiency on nitrogen metabolism of the symbiotic plant was studied from the distribution of calcium and of nitrogen and carbohydrate fractions in plant organs.

Nitrogen concentrations of all plant organs decreased with calcium deficiency. Addition of either a nitrogen or a calcium salt increased nitrogen concentrations. For roots as well as whole plants the effects of one salt were largely replaced by the other. These effects establish that calcium deficiency decreased the supply of fixed nitrogen from nodules to other organs. As weight of nodules was independent of calcium it follows that nodular efficiency was impaired.

Since nitrogen concentrations of nodules decreased rather than increased with calcium deficiency it is suggested that calcium deficiency interferes with the rate of reduction of nitrogen in the nodule rather than with the export of reduced nitrogen. Distribution of α-amino, amide, and ammonium nitrogen are consistent with this suggestion.

Nitrogen fixation was not limited by translocation of carbohydrates to nodules as calcium deficiency had little effect on the concentration of soluble carbohydrates and actually increased the concentration of starch in nodules.

Calcium deficiency depressed the calcium content of nodules so that nitrogen fixation may have been impaired by inadequate calcium for nodular structure or metabolism.

     

The effect of nitrogen and phosphorus deficiency on flavonol accumulation in plant tissues

The flavonol content of Arabidopsis thaliana and tomato seedlings was assessed in conditions of reduced nitrogen or phosphorus availability. In both systems, a significant inverse relationship was observed between nutrient availability and flavonol accumulation, with nitrogen limitation promoting the greatest increase in flavonols. A trial was established to determine the effects of decreased nitrogen and phosphorus availability on the flavonol content of leaf and fruit tissues of tomato plants (Lycopersicon esculentum cv. Chaser) in a commercial situation. Nutrients were supplied by a hydroponic system with nutrient regimes designed to provide the highest and lowest nitrogen and phosphorus levels with which it is possible to support plant growth and fruit set. Fruiting was abundant and tomato fruits were harvested at mature green, breaker and red stages of ripening; leaves were also harvested from the tops of the plants. All tissues were analysed for flavonol content using reversed‐phase high‐performance liquid chromatography. Flavonol accumulation in the leaves of mature tomato plants was found to increase significantly in response to nitrogen stress, whereas phosphorus deficiency did not elicit this response. Reduced nitrogen availability had no consistent effect on the flavonol content of tomato fruits. Phosphorus deficiency elicited an increase in flavonol content in early stages of ripening. Effects of nutrient stress on the flavonol content of tomato fruits were lost as ripening progressed. The findings suggest that nutrient status may be employed to manipulate the flavonol content of vegetative tissues but cannot be used to elevate the flavonol content of tomato fruit.     

Acclimation of Photosynthesis and Dark Respiration of a Submersed Angiosperm beneath Ice in a Temperate Lake

Ceratophyllum demersum L. remained physiologically active beneath ice of a southeastern Michigan lake. The effect of seasonally low photosynthetic photon flux density (PPFD) and cold but nonfreezing temperature on whole-plant physiology was studied. Net photosynthesis was measured at six temperatures and 12 PPFDs. Net photosynthesis, soluble protein concentration, ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) protein concentration, and Rubisco activity of winter plants were 32, 31, 33, and 70% lower, respectively, than those of plants collected in the summer. Optimum temperatures for net photosynthesis of winter and summer plants were 5 and 30[deg]C, respectively. Dark respiration of winter plants was up to 313% greater than that of summer plants. Reduced Rubisco activity and increased dark respiration interacted to reduce net photosynthesis. Interaction of reduced net photosynthesis and increased dark respiration increased CO2 and light compensation points and the light saturation point of winter plants. Growth of C. demersum was limited by the ambient phosphorus concentration of lake water during summer. Apical stem segments of winter-collected plants had 54 and 35% more phosphorus and nitrogen, respectively, than summer-collected plants. Physiologically active perennation beneath ice enabled C. demersum to accumulate phosphorus during the winter when it was most abundant. Partial uncoupling of phosphorus acquisition from utilization may reduce phosphorus limitation upon growth during the summer when phosphorus concentration is seasonally the lowest.     

巴郎山大叶醉鱼草叶片非结构性碳水化合物和氮分配的海拔响应

为深入认识和探讨植物对环境变化的生理生态响应和适应,以分布在川西巴郎山的大叶醉鱼草(Buddleja davidii)为研究对象,沿海拔梯度对植物叶片中非结构性碳水化合物(NSC)、可溶性糖和淀粉含量,氮含量和氮分配比例(光合系统氮分配比例P_P、细胞壁氮分配比例P_CW和其他组分氮分配比例P_other)等参数进行对比分析,探讨其沿海拔的变化趋势,以及叶片NSC、可溶性糖和淀粉含量与氮分配间的相关关系。结果显示：大叶醉鱼草叶片NSC、可溶性糖、淀粉和单糖含量随海拔的升高而增加,而可溶性糖/淀粉比值未发生显著变化,表明高海拔较高的NSC含量的累积是由可溶性糖和淀粉含量共同决定的,而可溶性糖含量的增加主要由单糖含量的变化引起。叶片氮含量和P_P在海拔间差异不显著,但P_CW和P_other分别随海拔升高而降低和升高。此外,随海拔升高,叶片NSC/N比值随之增加,这主要归因于随海拔升高而增加的NSC含量而非海拔间差异不显著的氮含量。NSC含量和可溶性糖含量均与P_...     

Alteration in nitrogen metabolism and plant growth during different developmental stages of green gram (<Emphasis Type="Italic">Vigna radiata</Emphasis> L.) in response to chlorpyrifos

Chlorpyrifos is a widely used broad-spectrum organophosphate insecticide in the agricultural practice. However, extensive use of this insecticide may lead to its accumulation in ecosystem, thus inducing the toxicity to crops and vegetables. To assess chlorpyrifos-induced toxicity in plants, we performed the experiment focusing on the growth and nitrogen metabolism of green gram plant (Vigna radiata L.). 20-days-old plants were subjected to chlorpyrifos at concentrations ranging from 0 to 1.5 mM through foliar spray in the field condition. Variation in root and shoot length, activities of nitrate reductase (NR) and content of nitrate, sugar, soluble amino acid and soluble protein were studied at preflowering (5 day after treatment, DAT), flowering (10 DAT) and postflowering (20 DAT) stages of plant development. Of the various concentrations of chlorpyrifos, 0.6 and 1.5 mM showed comparatively more severe toxicity to green gram plants by decreasing root and shoot length, nitrate, NR, soluble sugar and protein content where as at low concentration (0.3 mM) of chlorpyrifos proved stimulant for same parameter. Increase in soluble amino acid was observed in age and dose dependent manner. These results reflect strong parallelism between growth and biochemical activities of the model plant. Further lower dose of chlorpyrifos proved as stimulant where as at higher concentration proved detrimental for growth and nitrogen metabolism.     

Effect of sulphur fertilization on the nitrogen-sulphur relationships in alfalfa (Medicago sativa L. Pers.)

Summary Distribution of different nitrogen and sulphur fractions and N:S ratios in alfalfa (Medicago sativa L. Pers.) without and with S fertilization has been studied with a green house experiment. With increasing rates of applied S, the concentrations of total N, protein N, total S, protein S and total soluble S in the plant increased but those of non-protein N fractions (total soluble N, amino acid N, amide N, nitrate N) decreased. Thus the adequate supply of S in alfalfa increases the protein synthesis by accelerating protein metabolism. Sulphur application narrowed total N:total S ratios and widened protein N:protein S ratios. The data indicate that one part sulphur was required for every 11 to 12 parts of nitrogen to insure maximum production of protein. re]19750305     

Studies on the Physiology of Host-parasite Relationship in Orobanche. III. Carbohydrate and Nitrogen Metabolism of Host and Parasite

Determination of different carbohydrate and nitrogen fractions was made in tomato (Lycopersicum esculentum Mill.) and mustard (Brassica campestris L.) serving as hosts for Orobanche cernua and O. aegyptiaca respectively. Shoots of Orobanche were also subjected to such analyses. Infection raised the level of total reducing and total sugar in the host with a simultaneous decrease in the level of acid-hydrolyzable and total carbohydrates in the constituent organs of infected hosts. This has been explained to be due to predominance of hydrolytic activity in the infected host. Infection also brought about a depression in the proportion of sucrose to the pool of total sugar in the host. This was also possibly due to predominance of hydrolytic processes and retardation in the synthetic processes. Higher concentration of acid-hydrolyzable and total carbohydrates in Orobanche than in the host indicated a high demand for sugars by the parasite. The insignificant differences between the relative proportions of different nitrogen fractions to the pool of total nitrogen in healthy and infected hosts indicated that nitrogen metabolism was not deranged in any way due to infection. Orobanche always had a lower concentration of total soluble and total nitrogen than the host root.     

Nitrogen and Phosphorus in a Stretch of the Guadalupe River,Texas, with Five Main-Stream Impoundments by

Nitrogen and phosphorus were studied in a 168-km stretch of the Guadalupe River that had five main-stream impoundments. Flow through the study area was controlled by releases from these five reservoirs and from Canyon Reservoir, a deep-storage reservoir, located 30 km upstream. Parameters measured monthly on a diel basis at 16 stations were nitrate nitrogen, nitrite nitrogen, ammonia nitrogen, Kjeldahl nitrogen, inorganic phosphate phosphorus, organic phosphate phosphorus, and total phosphate phosphorus.Inorganic nitrogen concentrations observed in this study were as high or higher than that previously reported for other bodies of water. Nitrate nitrogen entered the study area in relatively high concentrations from Comal Springs which was a major source of water for the Guadalupe River. Water from Canyon Reservoir, the other major source of water, was relatively low in nitrate nitrogen. The concentration of nitrate nitrogen was, therefore, dependent in part upon the portion of the total river flow originating from the two sources. Increased discharge from Canyon Reservoir and utilization by plants in areas of high chlorophyll a resulted in low nitrate-nitrogen levels. Retention of water in reservoirs reduced the concentration of nitrate nitrogen due to increased utilization by plants in areas of low flow. Nitrate nitrogen, in general, reached seasonal minima in summer and maxima in winter. Nitrite nitrogen showed considerable variation with no meaningful pattern except that higher concentrations occurred in association with high chlorophyll a and high Kjeldahl nitrogen, regions and periods of low river flow, and large phytoplankton populations. There was no increase in concentration of any form of nitrogen in the vicinity of sewage outfalls and no downstream accrual.Phosphorus levels in the study area were as high or higher than those reported in studies of other bodies of water. Sewage treatment plants at New Braunfels and Seguin, Texas, were major sources of phosphorus to the Guadelupe River. Total phosphate phosphorus was determined to be the most critical phosphate parameter in assessing eutrophication. Seasonally, it ranged from a winter high to a summer low. Concentrations were highest immediately below sewage outfalls and decreased as water progressed downstream. Inorganic-phosphate-phosphorus concentrations showed no clear seasonal trend but were clearly associated with sewage outfalls. Since large standing crops of phytoplankton were observed in areas of low inorganic phosphate phosphorus, it was not considered to limit photosynthesis. Total organic phosphate phosphorus varied seasonally, with high concentrations occurring during the spring and low concentrations in the fall. Total organic phosphate phosphorus showed no correlation with sewage outfalls, but was correlated to a degree with total Kjeldahl nitrogen and chlorophyll a. No consistent pattern of diel fluctuations was evident for any phosphorus or nitrogen compounds analyzed.     

Changes in nitrogen content in malformed inflorescence of mango caused by Fusarium moniliforme Sheld. var. subglutinans Wr. et Rg.

Abstract

Fusarium moniliforme Sheld. var. subglutinans Wr. et Rg. causes malformations in young inflorescences of mango and seriously affects fruit formation. Quantitative studies of total, soluble and protein nitrogen contents of malformed inflorescence of two cultivars, ‘Himsagar’ and ‘Bombai’ were made. Healthy inflorescences of the former cultivar showed slightly higher nitrogen content than that of the latter. After infection, considerable increases in both soluble and protein fractions of nitrogen were observed in both host varieties. The proportion of these two nitrogen fractions, however, showed some changes in ‘Bombai’ but in ‘Himsagar’ it remained more or less unaltered.     

沙木蓼和沙枣对地下水位变化的生理生态响应I.叶片养分、叶绿素、可溶性糖和淀粉的变化

 在甘肃民勤沙生植物园内利用植物蒸腾耗水量观测场,研究了两种优势旱生植物沙木蓼(Atraphaxis frutescens)和沙枣(Elaeagnus angustifolia)叶片中的叶绿素、可溶性糖、淀粉和N、P、K含量等对不同地下水深度(1～3.4 m)的响应。结果表明：1) 1.4 m、2.4 m和3.4 m 3种不同的地下水深度处理,产生了3种差异显著的土壤水分梯度;2) 地下水深度的变化导致了这两种旱生植物叶绿素a、叶绿素b、叶绿素总量、叶绿素a与叶绿素b的比值等的显著变化(p<0.01);3) 地下水深度的增加引起了两种植物叶片可溶性糖含量的升高和淀粉含量的降低;4) 地下水深度的增加引起了两种植物叶片中N、P、K含量的降低;5) 不同的地下水深度引起沙枣和沙木蓼叶绿素a、叶绿素b、叶绿素总量、叶绿素a与叶绿素b的比值、N、P、K含量、可溶性糖和淀粉增加或减少的程度不同。沙枣是非豆科固氮植物,两者的差异是否与固氮作用相关还有待于进一步研究。     

砷对烤烟碳氮代谢及其产量和品质的影响

采用盆栽试验,系统地研究了砷对烤烟全生育期的碳氮代谢及其产量和品质的影响。结果表明,砷毒害对烤烟全生育期的碳代谢有显著影响,抑制了碳的同化和转化,降低了整个生育期的叶绿素含量、光合速率,造成了全生育期可溶性糖的积累,导致了生育后期淀粉含量的降低,最终使碳积累减少。砷毒害也改变了烤烟的氮代谢,造成生育前期氮同化能力的降低,表现出硝酸还原酶(NR)活性下降、总氮和蛋白质含量低于CK。砷毒害烤烟的氮转化表现活跃,提高了其中的游离氨基酸含量和谷氨酸-丙酮酸转氨酶(GPT)活性,最终导致烤烟生育中后期总氮和蛋白质的积累,但使整个生育期的烟碱含量降低。研究还表明,砷毒害降低了烤烟的产量和经济性状,增加了叶片中砷的积累,可溶性总糖含量的提高和糖氮比的协调虽好,但烟碱含量的降低和总氮、蛋白质含量的增加,以及糖碱比和氮碱比的失调,不利于碳氮代谢有关的化学品质形成。