Comparative growth of two peach seedling rootstocks under alkaline soil conditions

An almond X peach seed line, ‘Titan’ X Nemaguard (T X NG), which is tolerant to lime‐induced chlorosis, was compared to a susceptible seedling rootstock, Nemared, under alkaline conditions. The tolerant rootstock's growth was not affected by Fe stress, whereas the susceptible rootstock showed chlorosis which corresponded to approximately a 20% chlorophyll loss in the new foliage during the 18‐week stress period, a 62% decrease in shoot dry weight and a 22% decrease in plant height.     

Iron chlorosis and nitrate reductase activity in response to Fe stress and additional nitrate in sorghum

Effect of additional nitrate supply on chlorosis development at different levels of Fe stress was examined in iron efficient and inefficient sorghum cultivars. Nitrate reductase, the enzyme primarily responsible for nitrate reduction was estimated in roots and leaves as affected by Fe stress and additional nitrate.

Young leaves showed differences in chlorosis progression at Fe stress levels. Nitrate reductase activity was depressed in roots and young leaves when iron supply was reduced beyond certain level (<0.0015 gm FeSO₄/1). Addition of extra nitrate was not able to enhance NR activity when iron supply was lower than ½ level. It was inferred that nitrate utilisation and iron nutrition influence each other and some minimu level of iron supply is necessary for efficient enzyme activity.     

Mineral composition of peach leaves affected by iron chlorosis

The effect of Fe chlorosis on the mineral composition of field grown peach tree leaves was studied in two different areas. No significant differences in total Fe content were found, whereas 2,2’ bipyridyl extractable Fe, K and the K/Ca ratio were significantly affected in both experiments. Phosphorus and the P/Fe ratio were significantly affected only in one experiment.     

Mineral composition of peach leaves affected by iron chlorosis

Abstract

The effect of Fe chlorosis on the mineral composition of field grown peach tree leaves was studied in two different areas. No significant differences in total Fe content were found, whereas 2,2’ bipyridyl extractable Fe, K and the K/Ca ratio were significantly affected in both experiments. Phosphorus and the P/Fe ratio were significantly affected only in one experiment.     

Iron chlorosis and the iron status of soils

Abstract

The iron status of soils and its relation to iron uptake and iron‐chlorosis is discussed. In many soils, the soluble iron level is so low that rather than having to screen against iron uptake, plants are likely limited in their iron uptake by diffusion. The relationship between the plant root‐soil‐iron environment and the plant's ability to alter this environment is related to the development of iron‐chlorosis.     

Determination of iron chlorosis with extractable iron analysis in peach leaves

Iron (Fe) though indispensable for the biosynthesis of chlorophyll, but its total content in the plant was not associated with the occurrence of chlorosis. Iron, which is the ferrous‐iron (Fe²⁺) form—termed “active”; Fe— and extracted with weak acids and some chelating agents, has been closely related to Fe chlorosis. In this study, three different methods were tested in order to determine suitable methods for extractable‐Fe analysis in a Dixired peach cultivar. In the first two methods, o‐phenantroline (o‐Ph) and 1N hydrochloric acid (HCl) were used to extract Fe²⁺ from fresh leaves. In the third method, 1N HCl were used as an extractant on dried leaf samples. The relationship between chlorophyll content of the leaves and Fe extracted by the three methods, was statistically significant. Hydrochloric acid extraction with dried leaves which gave the highest significant correlation (r = 0.930) with chlorophyll content, can be used for the determination of Fe²⁺ ("active”; Fe) status in peach trees.     

Fruit quality of Redhaven and Royal Glory peach cultivars on seven different rootstocks

Two peach cultivars, Redhaven and Royal Glory, grafted on seven different rootstocks (Adesoto, Barrier 1, GF 677, Ishtara, Monegro, Penta, and peach seedling) were analyzed for tree vigor and yield. Fruit of similar ripeness (fruit firmness) was analyzed in terms of pomological (fruit weight, soluble solids content) and biochemical parameters (individual sugars, organic acids, phenolic acids in the flesh and peel, as well as flavonols and anthocyanins in the peel). A uniform effect of rootstock on tree size was evident in the cases of both cultivars. The Ishtara rootstock induced weak tree growth; Adesoto, Penta and peach seedling semivigorous growth; and Barrier 1, GF 677, and Monegro vigorous tree growth. We recorded higher yields in the Redhaven cultivar, while no significant differences in yield in the fourth growing season were found among the rootstocks for each cultivar. Rootstock had no effect on soluble solids in the Redhaven cultivar, while in the Royal Glory it did. Penta yielded the highest soluble solids content levels, while Adesoto and Monegro were associated with low levels. In the fruit from both cultivars, the rootstock had a significant influence on individual sugars, organic acids, and phenolic acids in the pulp. We also found that phenolic acids in the pulp and skin were more affected by the rootstock than other secondary metabolites analyzed, regardless of the cultivar.     

Soybean genotype evaluation for iron deficiency chlorosis using sodium bicarbonate and tissue culture

The evaluation of soybean genotypes for resistance to iron deficiency through field experiments is complicated by variation in symptom expression. The objective of this study was to develop a tissue culture technique that could distinguish between Fe‐efficient and Fe‐inefficient genotypes. Ten soybean genotypes varying in sensitivity to iron deficiency were planted at 5 locations and rated based on chlorosis expression. For the lab evaluation, friable callus of the ten genotypes was placed on a 4MSII medium amended with 10 mM NaHCO₃. Callus growth reduction relative to a control medium without NaHCO₃ was recorded. Callus weight of all cultivars was affected by the addition of NaHCO₃ however, significant differences in growth reduction among genotypes was observed. The high correlation between callus growth reduction and field chlorosis ratings observed (r²=0.92) and the fact that the expiant source plant can be grown to produce seed indicates that this technique would be useful in a soybean breeding program.     

Prognosis and correction of iron chlorosis in peach trees: Influence on fruit quality

A floral analysis for iron (Fe) content allowed for the prognosis of the incidence of the Fe chlorosis on peach (Prunus persica L. Batsch) trees (c.v. ‘Babygold 7’ grafted on seedlings) with high reliability. From a total of 35 peach trees analyzed, six of them had floral Fe dry matter concentrations less than 133 ppm and these six trees later developed severe Fe chlorosis in their leaves. The early detection and correction of Fe deficiency permitted us to measure the influence of Fe chlorosis on fruit quality as Fe correction resulted in a doubling of frait size and avoidance of the delay of frait ripeness that occurred on the Fe‐deficient trees.     

Differential response of citrus rootstocks to aluminum levels in nutrient solutions: I. plant growth 2

The objectives of this study were to determine and compare the Al tolerance of selected citrus rootstocks. Six‐month‐old seedlings of five citrus rootstocks were grown for 60 days in nutrient solutions. The solutions contained 7 levels of Al ranging from 4 to 1655 μM and similar P concentration of 28 μM. The nutrient solution pH was maintained at 4.0±0.1 and the temperature at 25±1°C. At high Al treatment levels, plants had thickened root tips and root caps covered with black gelatinous material. At high levels of Al treatments, seedlings of some rootstocks had yellow, mottled, and withered new leaves near end of experiment. New‐growth root lengths and shoot height responded differently to Al concentrations in the nutrient solution. New‐growth fresh weight of whole plants appeared to be the most sensitive indicator of Al tolerance. Based on response of fresh weight of whole plants to Al concentrations, relative Al tolerances of the rootstocks were Cleopatra mandarin > rough lemon > sour orange > Swingle citramelo > Carrizo citrange. The neutral or dividing Al concentrations in solution between beneficial and toxic effects were 371, 193, 189, 178, and < 100 μM Al, respectively, for the above rootstocks. Concentrations below or above the neutral Al levels caused either beneficial or toxic effects, respectively. The apparent optimum Al concentrations for the growth of whole plants were 163, 93, 89, 85, and <50 μM, respectively.     

Iron chlorosis of rice seedlings in calcareous soil under upland conditions

The farm of All India Coordinated Rice Improvement Project is located in Rajendranagar, Hyderabad, which lies in the Deccan Peninsula of India. Hyderabad is in latitude 17°N with about 500 m above sea level. The average annual rainfall of this area is about 750 mm. So it is called a semi-dry area.     

Iron deficiency stress response of Tolmiea Menziesii 1

The popular foliage houseplant, Tolmiea Menziesii (piggyback plant), grown in an all NO₃‐N, half‐strength Hoagland Solution No. 1 without Fe or with 0.5 g/liter Fe₂O₃ became severely Fe chlorotic and caused the nutrient solution pH to rise from 5.1 initially to above 7. Plants supplied 90 μM Fe‐EDTA also raised solution pH but did not become chlorotic. When Fe chlorotic plants were transferred to a solution with 0.5 gAiter Fe₂O₃, modified to contain 25 to 100% of the N as NH₄, the solution pH dropped to between 4.3 and 3.1, and the chlorotic plants regreened. However, if the pH of the modified solution was buffered above 7 with 1 g/liter CaCO₃, no regreening occurred. Solution pH also dropped if the solution lacked N, and there was a temporary regreening of Fe chlorotic plants before N deficiency chlorosis appeared. These solution culture results indicate that Tolmiea should be classified as an Fe inefficient plant.     

Effects of Fe deficiency chlorosis on yield and fruit quality in peach (Prunus persica L. Batsch)

The effects of iron (Fe) deficiency on fruit yield and quality were measured in two peach cultivars, Carson (yellow-skin fruit) and Babygold (red-skin fruit). In both cultivars, Fe deficiency caused major decreases in fruit fresh weight per tree and number of fruits per tree. Fruits from Fe-deficient peach trees had a smaller size, resulting in a large decrease in the percentage of commercially acceptable fruits, whereas fruit firmness was unaffected. In cv. Babygold, Fe deficiency greatly decreased the red color of the fruit skin. Part of these results was likely associated with a delay in fruit ripening. When fruits with similar appearance were compared, taking into account fruit size, color, and firmness, Fe deficiency generally led to higher concentrations of organic anions (especially succinate and quinate), vitamin C, and phenolic compounds and to lower total sugar/total organic acid ratios. This could lead to decreased fruit eating quality and to a slight improvement in fruit nutritional value.     

Iron nutrition in low chill peach for improving yield and fruit quality

Foliar fertilization and microbe supplemented iron (Fe) bioavailability can fulfill iron demand of plants. An experiment was performed to examine the effect of Psuedomonas fluorescens along with foliar spray ferrous sulfate on low-chill peach plants suffering from iron deficiency. Number of leaves per shoot, leaf area, chlorophyl content, Fe: Mn ratio of leaves, fruit yield and fruit physico-chemical parameters were recorded. The results showed a significant increase in leaves chlorophyl content, iron: manganese ratio of leaves, fruit yield, fruit length, fruit breadth, total soluble solids (T.S.S) and T.S.S and acid ratio with the inoculation of Pseudomonas fluorescens as well as foliar spray of ferrous sulfate, whereas, acidity of fruit pulp was decreased. Significantly higher number of leaves per shoot was also noted with foliar spray of ferrous sulfate. Pseudomonas fluorescens inoculation along with foliar spray of ferrous sulfate significantly increased leaves chlorophyl content, fruit length, T.S.S and T.S.S : acid ratio of fruit pulp.     

Alleviation of seeding chlorosis by plant growth regulators in drip-irrigated rice

Drip irrigation can produce high rice yields with significant water savings; therefore, it extends rapidly in water-scarce northern China. However, drip-irrigated rice seedlings often exhibit Fe chlorosis. The objective of this field experiment was thus to determine the ability of plant growth regulators to alleviate chlorosis in drip-irrigated rice seedlings. The study compared three plant growth regulators (1-naphthylacetic acid, NAA; sodium nitrophenolate, CSN; and diethyl aminoethyl hexanoate, DA-6) applied in two ways (seed-soaking and drip-application). The results showed that CSN increased root oxidation activity by 37% in the seed-soaking treatment and by 45% in the soil-application treatment. Seed soaking with NAA, CSN, and DA-6 increased the active Fe content in leaves by 8.8%, 17.5%, and 11.4%, respectively, compared with untreated seedlings. Iron absorption and SPAD values were both greater in the soil-application plots than in the seed-soaking plots. Among the plant growth regulators, CSN resulted in the highest yield (2.2% greater than untreated rice in the seed-soaking treatment and 12.8% greater than untreated rice in the soil-application treatment). In conclusion, CSN significantly improved root Fe uptake at the seedling stage and reduced chlorosis in drip-irrigated rice. Therefore, CSN drip application can be recommended for alleviating rice chlorosis in practical use.     

Influence of phosphorus nutrition and root zone temperature on growth and mineral uptake of peach seedlings 1

Siberian C peach seedlings (Prunus persica L. Batsch) were grown for 35 days in all combinations of Long Ashton nutrient solution containing P concentrations of 0.05, 0.5, or 5.0 mM and root zone temperatures (RZT) of 8°C, 16°C, and 24°C. At harvest, a significant interaction between solution P concentration and RZT occurred for shoot and root dry weight, root length, shoot P concentration and shoot P uptake. At 8°C RZT, P concentration and uptake but not growth were increased by P. At 16°C and 24° C RZT, growth was depressed at the 5.0 mM P level with shoot P concentration and uptake lower at 24°C than 16°C. The inflow of P to the peach shoot per unit root length was increased at high P concentration and low temperatures but was lower than whole plant inflow rates for apples. The growth depression at high temperature‐high P was related to increased young leaf chlorosis, reduced shoot Fe and a possible P/Zn imbalance.     

NaCl胁迫下温室内两个砧木的生理响应机制

为了探明NaCl胁迫下不同砧木耐盐性差异的生理机制,采用水培,研究了温室栽培条件下2个耐盐性不同的砧木(黑籽南瓜和超丰8848瓠瓜)在盐胁迫下的生长量、根系活力、离子含量和酶活性的变化.结果表明,盐胁迫下,2个砧木的地上部和根干质量、根系活力、Ca2 和Mg2 的含量及K /Na 比值均显著降低,叶片中Na 的含量虽然显著增加,但叶中Na 的含量显著低于根茎;超丰8848瓠瓜的SOD、POD活性、MDA含量均无显著变化,而黑籽南瓜的SOD、POD活性显著增强,MDA含量显著增加.低盐胁迫下Na 主要集中在根茎部,高盐胁迫下Na 主要集中在茎部.通过根茎阻止Na 向叶片运输,是2个砧木耐盐的主要生理机制.超丰8848瓠瓜较黑籽南瓜耐盐性强的生理机制在于其在盐胁迫下具有更高的根系活力.     

Calcium and bicarbonate effects on the growth and nutrient uptake of burley tobacco seedlings: Hydroponic culture 1

Abstract

In soilless production systems, water quality can have a major impact on the growth of plants. It has become evident that moderately alkaline water is a problem for tobacco transplant growers in some regions of Kentucky. To determine the level of bicarbonate (HCO₃ ^?) alkalinity, which is detrimental to burley tobacco transplants, and to better understand the effect of calcium (Ca) and the interaction of HCO₃ ^? and Ca on the growth of burley tobacco transplants grown in a float system, three levels of CaCl₂ (25,75, and 125 mg L^?1 Ca⁺⁺) in factorial combination with five levels of HCO₃ ^? (0, 122, 244, 366, and 488 mg HCO₃ ^?L^?1) were tested in nutrient solution culture. Four‐week‐old burley tobacco (Nicotiana tabacum L. var. KY‐907) seedlings were transplanted to 18‐L containers filled with aerated Hoagland's solution with the different levels of calcium and HCO₃ ^? for two weeks. High HCC₃ ^? alkalinity caused root system damage and plant growth inhibition, but did not induce iron (Fe) chlorosis. A significantly lower concentration of Zinc (Zn) was measured in the shoots as HCO₃ ^? levels in solution increased. In the presence of high calcium, plant growth was not significantly improved. No significant interaction of HCO₃ ^? and Ca on growth or nutrient uptake was observed in this study.     

旱地作物生育对土壤水肥耦联的响应研究进展

水肥是作物生长发育的基本物质基础,也是制约农业的主要因素。90年代以来我国在水肥对旱作 农业生产的协同效应方面做了大量的定性或定量研究工作,较为系统、深入地分析了旱地作物生长发育及产量对农田土壤水肥的响应。在总结分析的基础上指出水肥对旱地作物作用大小是随水肥相对平衡而变化。     

Response of five citrus rootstocks to iron deficiency

Citrus established in calcareous soils can be affected by iron (Fe)‐deficiency chlorosis which limits yield and the farmers' income. The degree of deficiency depends on the rootstock, but the resistance to Fe chlorosis still requires further investigation. To study physiological parameters of citrus rootstocks that could be used to evaluate resistance to Fe deficiency, plants of Troyer citrange (Citrus sinensis L. Osb. × Poncitrus trifoliata L. Raf.), Carrizo citrange, Volkamer lemon (Citrus volkameriana Ten. & Pasq.), alemow (Citrus macrophylla Wester), and sour orange (Citrus aurantium L.) were grown in nutrient solutions with 0, 5, 10, 15, or 20 μM Fe. For each rootstock, plant height, root and shoot dry weights, and concentration of Fe in the shoots and roots were measured at the end of the experiment. Chlorophyll (CHL) concentration was estimated throughout the experimental period using a portable CHL meter (SPAD‐502) calibrated for each rootstock. At the end of the experiment, CHL fluorescence parameters were measured in each rootstock with a portable fluorimeter. Maximal and variable fluorescence values indicated that the photochemistry of Troyer was more affected by a low concentration of Fe in the nutrient solution than that of other rootstocks. To compare rootstocks, the absolute CHL concentration was converted into relative yield by employing a scaling divisor based on the maximum value of total CHL in plants without Fe‐deficiency symptoms. Exponential models were developed to determine the minimum Fe concentration in nutrient solution required to maintain leaf CHL at 50% of the maximum CHL concentration (IC50). Models were also developed to assess the period of time the rootstocks were able to grow under Fe‐stress conditions before they reached IC50. Volkamer lemon and sour orange needed the lowest Fe concentration (between 4 and 5 μM Fe) to maintain IC50, and Troyer citrange had the highest Fe requirement (14 μM Fe). Citrus macrophylla and Carrizo citrange required 7 and 9 μM of Fe, respectively. Similarly, Volkamer lemon and sour orange rootstocks withstood more days under total Fe depletion or with a low concentration of Fe (5 μM Fe in nutrient solution) until they reached IC50, compared to the other rootstocks. The approach used led to a classification of the rootstocks into three categories, regarding their internal tolerance to Fe chlorosis: resistance (sour orange and Volkamer lemon), intermediate resistance (C. macrophylla and Carrizo citrange), and reduced resistance (Troyer citrange).