INFLUENCE OF ROOTSTOCK ON MINERAL UPTAKE AND SCION GROWTH OF ‘GOLDEN DELICIOUS’ AND ‘ROYAL GALA’ APPLES

Influence of four rootstocks (M.9, MM.106, MM.111, and local seedling) on the scion leaf and fruit mineral concentrations, tree growth, yield and fruit quality attributes of ‘Golden Delicious’ and ‘Royal Gala’ apples during four seasons (2008–2011) were significant. The mechanisms behind the influence of rootstock on scion vigor and yield was that the rootstock brought about its effects upon the scion by influencing the amounts of minerals taken up and translocated to the scion. ‘Royal Gala’ and ‘Golden Delicious’ trees on seedling had the highest efficiency in calcium (Ca) and potassium (K) uptake. Whereas, trees of these cultivars on M.9 were more efficient in nitrogen (N), manganese (Mn) and iron (Fe) uptake. MM.106 had the highest efficiency in phosphorous (P) uptake, and M.9 had the lowest K and Ca uptake. The highest N- fruit concentration and the lowest Ca-fruit concentration were observed in cultivars on M.9.     

Rootstock Effect on Nutrient Concentration of Sweet Cherry Leaves

The present investigation aimed to study the leaf mineral composition of sweet cherry trees on different rootstocks, since the literature data on uptake efficiency of different rootstocks is inconsistent. Results confirmed the different uptake efficiency of rootstocks. The efficiency of ‘GiSelA 6’ root is emphasized in uptake and supply of leaves with nitrogen (N), phosphorus (P), potassium (K), zinc (Zn), boron (B), and manganese (Mn), but trees on this rootstock tend to develop calcium (Ca), magnesium (Mg), and copper (Cu) deficiencies. The Prunus mahaleb rootstocks on calcareous sandy soil are efficient supplier of N, P, K, Ca, Mg, Fe, and Cu, but this root tends to develop Zn, B, and Mn deficiencies. Prunus avium seedling as rootstock proved to be less efficient in supply of leaves by N, P, K, Ca, and Cu. Prunus fruticosa ‘Prob’ root showed tendency in developing several leaf nutrient deficiencies. The applied fertilizer program led to low nutrient levels or even deficiency symptoms in leaves.     

Elemental and chemical concentration in peach tree short life and healthy trees

Abstract

Elemental concentrations of N, P, K, Ca, Mg, Fe, Al, Zn, Mn, and Cu in peach tree short life (PTSL) trees were compared to concentrations in apparently healthy trees in the same orchard. Leaf and stem concentration of K were significantly less and concentrations of Fe and Al were significantly greater in PTSL trees than healthy trees. Leaf concentrations of Ca and Mg and stem concentrations of N, P, and Cu were also significantly less in PTSL trees than healthy trees. Increased levels of Fe and Al and a K:Fe ratio of less than 150:1 in the leaves and stems was associated with PTSL.

There were no detected differences in prunasin, amino acid, or sugar content of PTSL and healthy trees in leaf and stem samples, but significant differences in elemental content suggest some type of stress on the root system of PTSL trees.     

LEAF MINERAL COMPOSITION OF ‘NOVA’, ‘ROBINSON’ AND ‘FREMONT’ MANDARIN CULTIVARS ON DIFFERENT ROOTSTOCKS

Rootstock selection has a critical importance for mineral nutrition of budded cultivars. This study was conducted at the experimental farm of Mustafa Kemal University, Dörtyol, Turkey. The aim of this study was to investigate the effect of sour orange, Troyer and Carrizo citrange rootstocks on the leaf nutrient contents of ‘Nova’, ‘Robinson’, and ‘Fremont’ mandarin cultivars in the 2004 and 2005 growing seasons. Carrizo citrange was examined for nitrogen (N), potassium (K), magnesium (Mg), sodium (Na), and manganese (Mn); Troyer citrange for iron (Fe); and sour orange for calcium (Ca) and zinc (Zn) were superior on the others. Nitrogen, phosphorus (P) and Mg levels of mandarin leaf budded on sour orange were under or just above the deficiency threshold. Potassium, Mn, and Zn content of ‘Robinson’; P, Ca and Fe content of ‘Fremont’; and Cu content of ‘Nova’ were statistically higher. Therefore, it can be concluded that Carrizo rootstock may be suggested for the region and regions with similar ecological conditions.     

EFFECT OF CITRUS ROOTSTOCKS ON LEAF MINERAL COMPOSITION OF ‘OKITSU’, ‘CLAUSELLINA’, AND ‘SILVERHILL’ MANDARIN CULTIVARS

Citrus performance is strongly related with rootstock. This study was conducted to investigate leaf nutrient contents of ‘Okitsu’, ‘Clausellina’ and ‘Silverhill’ mandarin cultivars budded onto sour orange, ‘Carrizo’ and ‘Troyer’ citrange rootstocks in Dörtyol, Turkey in 2004 and 2005. The maximum nitrogen (N), potassium (K), and copper (Cu) contents were determined for ‘Clausellina’; phosphorus (P) for ‘Okitsu’; and sodium (Na) for ‘Silverhill’. Calcium (Ca), magnesium (Mg), iron (Fe), manganese (Mn), and zinc (Zn) uptake were similar for the mandarin cultivars. ‘Carrizo’ citrange at N, K, Mg, Mn, and Cu uptake; ‘Troyer’ citrange at N, P, K, and Fe uptake; and common sour orange at Ca, Zn, and Na uptake was superior on the other rootstocks. It was observed that ‘Carrizo’ and ‘Troyer’ citrange rootstocks had advantages over sour orange in nutrient uptake. Thus, growth performance, yield, and quality parameters considered, ‘Carrizo’ and/or ‘Troyer’ citranges could be suggested as rootstocks for the studied mandarin cultivars under similar ecological conditions.     

Mineral nutrition during establishment of golden delicious ‘smoothee’ apples on dwarfing rootstocks and interstems

This study was conducted to determine the influence of 4 interstems (EM.27 EMLA, Mark, M.9 EMLA, and EM.26 EMLA) and 8 rootstocks (EM.27 EMLA, Mark, M.9 EMLA, EM.26 EMLA, M.7A, MM. 106 EMLA, MM. 111 EMLA, and seedling) with and without interstems on foliar element concentrations [nitrogen (N,) phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), manganese (Mn), iron (Fe), zinc (Zn), boron (B)] of the Golden Delicious ‘Smoothee’ (Malus domestica, Borkh). The trees were planted in 1990 and the experiment was conducted until 1996. Soil pH was low (pH=5.9) before planting but liming raised the pH to 6.5 by the 4th year after planting. Soil P was adequate, K and Mg were high, and Ca was low based on local recommendations for apples. The year by year variation in foliar element concentrations was much higher than rootstock and interstem effects. Differences among interstems and rootstocks were important as foliar element concentrations approached those of deficiency or toxicity. In this study, K decreased to deficiency concentrations by the end of the experiment except for seedling rootstocks, which slightly increased. Foliar Ca was deficient for all interstems and rootstocks at the start of the experiment, but increased extensively for M.9 EMLA and EM.26 EMLA rootstocks across years. Foliar Mn increased to nearly toxic concentrations (300 μg g^‐1) in EM.27 EMLA and Mark rootstocks, whereas the other rootstocks did not. No deficiency or toxicity symptoms were noted for any elements during this study. These results indicate that a single range of foliar nutrient concentrations can be used as an aid for determining fertilization rates for the apple rootstocks and interstems used in this study. However, individual rootstocks vary in the rate at which they approach toxicity and deficiency concentrations, which needs to be known to prevent mineral nutritional related problems in commercial apple orchards.     

Fruit Production and Nutrient Status in Grapefruit on Five Rootstocks

A trial was conducted during two years (2000/01 and 2001/02) on two sites using ‘Shambar’ grapefruit trees grafted to five rootstocks. The sites were located on the Greek island of Kos to evaluate the effect of rootstock and location on fruit production and leaf mineral composition of ‘Shambar’ grapefruit. Results indicated that yields were higher in 2001/02 than in 2000/01 and these differences were greater at site 2. Leaf nitrogen (N), potassium (K), zinc (Zn), and to some degree phosphorus (P) content was slightly deficient to deficient for the majority of the samples taken. Calcium (Ca) and magnesium (Mg) levels ranged from normal to high. The copper (Cu) and iron (Fe) leaf contents and the manganese (Mn) content of most samples were in the optimum range. The interactions between rootstock, site, and year upon yield and nutrient content were statistically significant. There were also significant correlation coefficients between yield and nutrient content as well as among the nutrients.     

Mineral element concentration of two barley cultivars in relation to water deficit and aluminum toxicity

The separate and combined effects of water and Al stress on concentrations of P, K, Ca, Mg, Fe, Mn, Zn, Cu, B, Al, Sr, and Ba were determined in tops of ‘Dayton’ (Al‐tolerant) and ‘Kearney’ (Al‐sensitive) barley (Hordeum vulgäre L.) grown in an acid, Al‐toxic, Tatum subsoil (clayey, mixed, thermic, Typic Hapludult). Plants were grown 4 weeks in a plant growth chamber at high (pH 4.7) or low (pH 6.6) Al stress. During the last 2 weeks they were also subjected to low (‐20 to ‐40 kPa), moderate (‐40 to ‐60 kPa), or high (‐60 to ‐80 kPa) water stress. In general, Al stress had a greater overall effect on mineral element concentration of tops than water stress. Aluminum stress significantly decreased concentrations of P, Ca, and Mg and increased concentrations of Zn, Sr, and Ba, irrespective of the cultivar or water stress treatment. Cultivar differences in Mn concentration were observed with Al stress under all water stress conditions. In each case, Mn concentration was lower in ‘Kearney’ than in ‘Dayton’. Potassium, Ca, and Mg were lower in ‘Kearney’ than in ‘Dayton’ only at low and moderate water stress, under low Al stress, ‘Kearney’ had significantly higher concentrations of K and Ca than did ‘Dayton’ under all water stress conditions. The effects of water stress on mineral element concentration varied greatly with cultivar, Al stress treatment, and severity of water stress. Under high Al stress, increasing drought conditions from low water stress (‐20 to ‐40 kPa) to high water stress (‐60 to ‐80 kPa) significantly increased the concentrations of Ca, K, Zn, Sr, and Ba in Al‐sensitive ‘Kearney’ and reduced the concentrations of Zn, Sr, and Ba in Al‐tolerant ‘Dayton'; P and Mg concentration were unaffected by water stress. In contrast, under low Al stress, a corresponding increase in water stress significantly increased the concentrations of Ca and reduced that of P in ‘Kearney’ and increased Ca and B concentration in ‘Dayton'; Mg concentrations were unaffected in either cultivar. Thus, it appears that Al stress and water stress had opposite effects on Ca accumulation in barley tissue.     

Standardization of Litchi Leaf Nutrient Composition for Tissue Analysis in Sub Tropics of India

ABSTRACT

Variation in leaf nutrient composition with leaf age and position of leaflets was assessed for ‘Calcuttia’ and ‘Dehradun’ litchi cultivars under loam to sandy loam soils of north India. Leaf samples were collected from first to sixth pair of leaflets starting from the apex of terminal shoots to downward positions during December to May at monthly intervals at two locations for three successive years. The leaves were analyzed for N, P, K, Ca, Mg, Fe, Zn, Cu and Mn concentrations. In both litchi cultivars, leaf N, P, Zn and Cu contents remained more in young leaves; whereas, leaf Ca, Mg, Mn and Fe contents were observed higher in older leaves. Leaf K concentration exhibited inconsistent patterns; however, leaf K concentration in pair of leaflets on the shoot declined basipetal, being maximum in upper pair of leaflets and minimum in lower pair of leaflets. Levels of macro and micronutrients exhibited a degree of stability at second and third pair of leaflets when sampled during February–March. Leaf compositions differed significantly during active vegetative growth, flowering, and fruit development. The results revealed that 4–5 months old leaves from autumn flush at second and third pair of leaflets from the apex of terminal litchi shoots at the advent of panicle initiation (February–March) should be collected to assess the nutritional concentrations of litchi orchards under North India conditions.     

Effect of aluminum on growth and chemical composition of marigolds

Marigold (Tagetes erecta L. cv. ‘Discovery Yellow’, “Perfection Yellow’, ‘Inca Yellow’, and ‘Merrymum Yellow') were grown in aluminum (Al) solution culture concentrations of 0, 1, or 4 mg/L. Aluminum increased root length and weight, but had no effect on stem and leaf weight. Uptake and stem and leaf tissue nutrient concentration of phosphorus (P), calcium (Ca), and magnesium (Mg) were reduced by the Al treatments. The Al treatments increased stem and leaf concentrations of potassium (K) and decreased the concentrations of manganese (Mn), iron (Fe), copper (Cu), and zinc (Zn). No typical Al‐toxicity symptoms were observed in the roots. Root stunting caused by Fe toxicity was alleviated by the Al treatments.     

Effects of excess aluminum on mineral uptake in mycorrhizal sorghum

Soil acidity is often associated with toxic aluminum (Al), and mineral uptake usually decreases in plants grown with excess Al. This study was conducted to evaluate the effects of Al (0, 35, 70, and 105 μM) on Al, phsophorus (P), sulfur (S), potassium (K), calcium (Ca), magnesium (Mg), iron (Fe), manganese (Mn), zinc (Zn,) and copper (Cu) uptake in shoots and roots of sorghum [Sorghum bicolor (L.) Moench, cv. SC283] colonized with the vesicular‐arbuscular mycorrhizal (VAM) fungi isolates Glomus intraradices UT143–2 (UT143) and Glomus etunicatum UT316A‐2 (UT316) and grown in sand (pH 4.8). Mycorrhizal (+VAM) plants had higher shoot and root dry matter (DM) than nonmycorrhizal (‐VAM) plants. The VAM treatment had significant effects on shoot concentrations of P, K, Ca, Fe, Mn, and Zn; shoot contents of P, S, K, Ca, Mg, Fe, Mn, Zn, and Cu; root concentrations of P, S, K, Ca, Mn, Zn, and Cu; and root contents of Al, P, S, K, Ca, Mg, Fe, Mn, Zn, and Cu. The VAM effects on nutrient concentrations and contents and DM generally followed the sequence of UT316 > UT143 > ‐VAM. The VAM isolate UT143 particularly enhanced Zn uptake, and both VAM isolates enhanced uptake of P and Cu in shoots and roots, and various other nutrients in shoots or roots.     

Development of Standard Concentrations of Foliar Nutrients for Saskatoon

Soil and foliar samples were collected from saskatoon orchards in Saskatchewan, Manitoba, and Alberta, Canada from 1997 to 1999 and analyzed for macro- and micronutrient content. Foliar samples were collected twice a month from the end of May until September in 1997 to examine the pattern of change in foliar nutrient concentrations throughout the season and to determine the most stable time period for foliar sampling. This period was determined to be from the last week in July until mid-August. Nutrient concentrations of foliar samples collected during this period from 1997 to 1999 were summarized according to the mean, median, minimum, and maximum values. Mean foliar nutrient concentrations were as follows: 2.48% nitrogen (N), 0.18% phosphorus (P), 1.15% potassium (K), 0.15% sulfur (S), 1.52% calcium (Ca), 0.50% magnesium (Mg), 6.9 ppm copper (Cu), 106 ppm iron (Fe), 124 ppm manganese (Mn), 16 ppm zinc (Zn), and 27 ppm boron (B). A number of significant positive correlations were found between soil and foliar levels of a nutrient, with the majority of these correlations occurring for the nutrients Cu, P, and Mn. Another study conducted during 2001–2002 examined differences in the foliar nutrient concentrations of the saskatoon cultivars ‘Smoky’ and ‘Thiessen’ sampled from nine orchards in Saskatchewan. Foliar concentrations of N, K, S, Ca, Mg, Cu, Mn, Zn, and B were significantly higher in ‘Smoky’ than in ‘Thiessen,’ whereas foliar K content was higher in ‘Thiessen’ than in ‘Smoky’.     

Differential response of citrus rootstocks to aluminum levels in nutrient solutions: II. Plant mineral concentrations 2

The objective of this study was to determine relations between Al effects and mineral concentrations in citrus seedlings. Six‐month‐old seedlings of five citrus rootstocks were grown for 60 days in supernatant nutrient solutions of Al, P, and other nutrients. The solutions contained seven levels of Al ranging from 4 to 1655 μM. Al and similar P concentrations of 28 μM P. Aluminum concentrations in roots and shoots increased with increasing Al concentration in the nutrient solution. Aluminum concentrations in roots of Al‐tolerant rootstocks were higher than those of Al‐sensitive rootstocks. When Al concentrations in nutrient solution increased from 4 to 178 μM, the K, Mg, and P concentrations in roots and the K and P levels in shoots increased. Conversely, Ca, Zn, Cu, Mn, and Fe in the roots and Ca, Mg, Cu, and Fe in the shoots decreased. The more tolerant rootstocks contained higher Fe concentrations in their roots than did the less tolerant ones when Al concentrations in solution were lower than 308 μM. Concentrations of other elements (Ca, K, P, Mg, Zn, and Mn) in roots or shoots exhibited no apparent relationship to the Al tolerance for root or shoot growth of the rootstocks. Calcium, K, Zn, Mn, and Fe concentrations in roots and Mg and K concentrations in shoots of all five rootstocks seedlings had significant negative correlations with Al concentrations in corresponding roots or shoots.     

Aluminum tolerance,mineral nutrition,and growth of ‘Helleri’ holly in solution culture

‘Helleri’ holly (Ilex crenata Thunb. ‘Helleri') plants were grown in solution culture at aluminum (Al) concentrations of 0, 6, 12, 24, and 48 mg.L^‐1 for 116 days. Aluminum did not affect root or crown index, stem length growth, plant dry weight, or leaf area. Aluminum treatments significantly increased Al uptake and reduced nutrient uptake of magnesium (Mg), calcium (Ca), zinc (Zn), and copper (Cu) on some sampling dates. Iron (Fe) and manganese (Mn) uptake decreased on most sampling dates but increased on some with Al treatments. Potassium (K), phosphorus (P), and boron (B) uptake were significantly affected by Al, decreasing and increasing at different sampling dates. Although plants preferentially took up ammonium‐nitrogen (NH₄ ⁺‐N) in all treatments (including 0 Al controls), neither NH₄ ⁺‐N nor nitrate‐nitrogen (NO₃ ‐N) uptake were affected by Al. Tissue concentrations of P, K, B, Zn, and Al increased with Al treatment; whereas tissue Ca, Mg, and Cu concentrations decreased with increasing Al. Iron and Mn tissue concentrations exhibited increases and decreases in different tissues. Results indicated that ‘Helleri’ holly was tolerant of high concentrations of Al.     

Seasonal Changes in Nutrient Concentrations of ‘Newhall’ and ‘Skagg's Bonanza’ Navel Oranges

Seasonal changes in nutrient concentrations of leaf and fruit structural parts (rind and pulp) from ‘Newhall’ (Citrus. sinensis Osbeck) and ‘Skagg's Bonanza’ (C. sinensis Osbeck) navel oranges were investigated during fruit development in two successive years. Leaf calcium (Ca), manganese (Mn), and potassium (K) concentrations were relatively constant throughout the whole season with the exception of an increase of K at stage 1, the period of fruitlet growth [before 80 days after full bloom (DAFB)], whereas the magnesium (Mg), boron (B), iron (Fe), and zinc (Zn) concentrations declined distinctly during stage 2 (80–180 DAFB), the period of fruit rapid enlargement. In rind, Ca, B, Fe, and Mn concentrations reached the greatest levels at stage 2, different from K and Mg, which increased at stage 1 and decreased thereafter. In pulp, concentrations of Ca, K, Mg, and Mn declined gradually with time, whereas a small rise in B toward the end of sampling and a clear increase of Fe at stage 2 were observed. It was suggested that ‘Newhall’ required greater B inherently in fruits as the cultivar had greater B concentrations in fruit parts and had greater rind/leaf B concentration ratios than ‘Skagg's Bonanza.’ ‘Newhall’ had relatively greater rind Ca content and exhibited Ca distribution more uniformly within its fruit parts, which probably enhanced the crack resistance.     

Salinity-Induced Changes in Ion Concentrations of ‘Hass’ Avocado Trees on Three Rootstocks

ABSTRACT

The effect of salinity (1.5, 3.0, 4.5, or 6.0 dS m^{? 1}) on ion concentrations [magnesium (Mg), calcium (Ca), potassium (K), sodium (Na), and chloride (Cl)] of one-year-old ‘Hass’ avocado (Persea americana Mill.) trees on one of three rootstocks [‘Duke 7’ (D7), ‘Toro Canyon’ (TC), or ‘Thomas’ (TH)] was investigated. Concentrations of Mg decreased in roots, stems, and older leaves with increasing substrate salinity. Salinity had no effect on Ca concentration of the trees. Potassium concentrations decreased in roots of all trees and stems of trees on TH. Potassium concentrations either remained unchanged or increased at salinity levels of 3.0 dS m^{? 1} and above in leaves and buds of all trees. Sodium increased in roots and woody organs in trees on all rootstocks. Leaf Na concentrations increased with salinity in trees on D7 and TH, but not TC. Chloride increased in all organs of all trees with increasing salinity, but to the greatest extent in trees on TH and to the least extent in trees on TC. At high substrate salinity concentrations, leaves of trees on TH rootstock had the highest leaf concentrations of Na and Cl, and the highest Na:K ratios. Sodium and chloride concentrations were correlated with necrosis in older leaves of TH, but less so in leaves of trees on TC or D7. Based on percent necrosis in older leaves with increased salinity, trees on TH performed poorest, whereas trees on TC exhibited the greatest salt tolerance. Leaf necrosis was consistently observed at Cl concentrations of 4 mg g^{? 1} or more, and at Na:K ratios of 0.01 or more in older leaves. Chloride concentration and Na:K ratio in older leaves appears to be a useful marker for salinity tolerance screening in avocado rootstocks. The relative tolerance of the various rootstocks appeared to be due primarily to their ability to exclude Na and Cl from the leaves.     

Correlations Between Soil Exchangeable Ca2+, Mg2+, K+ and Foliar Nutrient Concentrations in Mature Biological Olive Groves (Olea europaea L., cv. ‘Chondrolia Chalkidikis’)

Leaf and soil samples were taken and analyzed from two mature biological olive groves (Olea europaea L., cv. ‘Chondrolia Chalkidikis’), in Thessaloniki, Macedonia, Northern Greece, in order to determine the correlations between soil exchangeable cations and foliar calcium (Ca), magnesium (Mg) and potassium (K) concentrations, and the interrelations among leaf nutrients. Τhe nutritional requirements of trees for both biological groves were exclusively based on patent kali supply and nutrient recycling (via pruning material and weed cut recycling). Foliar K, Ca and Mg were positively correlated with soil exchangeable K, Ca and Mg, in the 40–60 cm layer, then in the 20–40 cm layer. Synergistic uptake mechanisms among Ca²⁺, Mg²⁺ and K⁺ probably exist. Leaf N was negatively correlated with foliar K, and positively with leaf Ca, Mg and manganese (Mn). Foliar P was negatively correlated with leaf Ca, Mg and Mn, while foliar Ca was positively correlated with leaf Mg and Mn. Foliar Mg was positively related with leaf Mn. High phosphorus (P) may decrease leaf Ca, Mg and Mn. Enhanced Ca may increase leaf Mg and Mn, while high Mg may also enhance foliar Mn. Finally, based on the determination of foliar nutrient concentrations, the nutritional requirements of olive trees in Ca, Mg, K, P, Fe, Zn were sufficiently (or over-sufficiently) satisfied. However, additional organic fertilization is needed, in order to achieve optimum levels of N, B and Mn (since their foliar concentrations were slightly insufficient). The correlations between leaf and soil exchangeable Ca, Mg and K, as well as among foliar nutrients should be taken into consideration, in order to achieve successful organic fertilization for mature biological olive groves, and to avoid nutritional imbalances and disorders.     

Nitrogen rate and source affects leaf elemental concentration and plant growth in muscadine grapes

Leaf concentrations of nitrogen (N), phosphorus (P), potassium (K), iron (Fe), and manganese (Mn) in ‘Sterling’ muscadine grapes (Vitis rotundifolia Michaux) grown for two years in sand culture were not influenced by different N‐fertilizer sources. Leaf zinc (Zn) and copper (Cu) were higher with ammonium nitrate (NH₄NO₃)than ammonium sulfate [(NH₄)₂SO₄]. Shoot growth was greatest with NH₄NO₃. Leaf Ca, Mg, Mn, and Cu content decreased and leaf N increased as N‐fertilizer rates were raised. Plant growth was positively correlated with leaf N, but was negatively correlated with leaf Ca, Mg, Fe, Cu, and Mn content. Percent Mg in the leaves was reduced when N levels, regardless of N source, were raised from the low (1.8 mM) to the middle (5.4 mM) rate. High leaf‐N levels were correlated with lower Ca and Mg in the leaves, indicating a relationship between N fertilization and the late‐season Mg deficiency often observed in muscadine grapes.     

Nutritional Status,Yield, and Fruit Quality of “Encore” Mandarin Trees Grown in Two Sites of an Orchard with Different Soil Properties

Abstract

The nutrient status [annual fluctuation of leaf nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), iron (Fe), manganese (Mn), and zinc (Zn)], yield and fruit quality [soluble solids concentration (SSC), titratable acids (TA), SSS/TA and juice content] of “Encore” mandarin trees cultivated in two sites of the same orchard were studied. The trees were grafted on Carrizo citrange rootstock and grown under identical conditions, apart from some soil properties. Soil B (site B of orchard) contained more K, Ca, Mg, and organic matter than soil A (site A of orchard). The patterns of annual variation of leaf nutrient concentrations were similar in both soils, although leaf concentrations of Ca, Mg, Mn, and Fe in soil A were significantly higher than those of soil boron (B), while leaf K concentrations were significantly lower. The mineral analyses of the leaves revealed some interesting antagonisms between K–Mg, K–Ca, and K–Mn. Manganese deficiency was especially limited in the trees grown in soil B. The average fruit yield per tree in soil A, on two-year basis, was significantly higher than this in soil B. The significantly higher water infiltration rate in soil B, in contrast to soil A, seemed to be the dominant factor responsible for the differences among the two sites in yielding and leaf mineral composition.     

Nutritional Status of Pollen and Needles of Diverse Pinus Sylvestris Populations Grown at Sites with Contrasting Pollution

Pollen may serve as a biological indicator for air pollution stress in plants. However, knowledge of pollen mineral composition and its relationship to environmental and genetic factors is very limited. We studied the concentrations of macro- and micronutrients in pollen and needles for seven European Scots pine (Pinus sylvestris L.) populations grown in two 15-yr-old provenance plantations with contrasting pollution levels. One site was located near a phosphate fertilizer factory, and the other in an area free of acute air pollution. We also tested the relationship between tree age and pollen nutrient composition by sampling 60-yr-old trees of local origin in both sites. No population differences were found in nutrient concentrations in pollen. However, there were significant differences among populations in needle concentrations of K, Mg and Zn, as well as significant site x population interaction for Mn concentration. In pollen, populations at the polluted site had significantly higher concentrations of S, Mn, Al, Na, Cu, Ni and Cd, and lower Zn. Average concentrations of S, P, Mn and Cd was lower in pollen of 60-yr-old than 15-yr-old Scots pine trees. Pollen concentrations of P, K, Ca, Mg, Fe and B were similar between sites and not related to the concentration of these elements in needles. Therefore, by analyzing the chemical composition of pollen it is not possible to detect any nutritional disorders for P, K, Ca and Mg in plants, and it seems unlikely that nutrient analyses of pollen have an advantage over analyses of foliage as a bioindicator of pollution. However, enhanced accumulation by pollen of such elements as Al, S, Mn, Cu, Ni and Cd at the polluted site may adversely affect pollen function.