Regulation of Mineral Redistribution in Pod-Bearing Soybean Explants

On the way from the roots to the seeds during reproductive developmentin soybean (Glycine max), a large proportion of the mineralspass through the leaves rather than travelling directly viathe xylem. This direct and indirect movement of mineral nutrientshas important implications for mineral redistribution, seeddevelopment and leaf senescence. Therefore, we have studiedthe role of cytokinin and mineral flux from the roots in regulatingmineral redistribution from the leaves to the seeds using explants,i.e. a leaf, a pod and a subtending stem segment, with theirbases immersed in treatment solutions. Thus, defined solutionscontaining cytokinin and/or minerals can be substituted forthe roots. When explants (excised at early-mid podfill) aresupplied H₂O only, leaf N, P, K, Mo, Mg, Zn, Fe, B, Cu, Ca,and Mn decline, ranging from 93% for Mo to 38% for Fe. In explantson H₂O, N, P, K, Mo, Mg, Zn, and Fe appear to be redistributedfrom the leaves to the seeds, while the B, Cu, Ca, and Mn lostfrom the leaves do not seem to move to the seeds. Although amixture of minerals resembling xylem sap can delay net lossof these elements from the leaves, it does not prevent the decreases.The cytokinin zeatin (4.6 µM) inhibits the loss of N,IC, Mo, Mg, Zn, Fe, B, Cu, Ca, and Mn from the leaves, but notthat of P. When combined with minerals, zeatin not only preventsthe loss of the minerals from the leaves but may even greatlyincrease them with the possible exception of Zn, Fe, and Cu.Supplying the mineral nutrient mixture increases the quantitiesof N, P, K, Mg, Cu, and B in the seeds but not Zn, Fe, Mn, Ca,and Mo. For those minerals, especially N, where zeatin inhibitsefflux from the leaves, it may reduce the amounts in the seeds,but it does not change P, K, Mg, and Ca. The accumulation andredistribution patterns of the different mineral nutrients showmany dissimilarities thereby suggesting differences in the controlof their distribution. Key words: Cytokinin, mineral transport, seed development, senescence     

Accumulation and Distribution of Nutrients in Fruits of Castor Bean (Ricinus communis L.)

The nutrition of developing fruits of Ricinus communis was studiednear Perth, Western Australia, where the species grows as aweed on poor sandy soil. Fruits required 60 days to mature anddehydration of the capsule began 20 days before the seeds ripened.Mature seeds accumulated 49 per cent of the fruit dry matterand over 80 per cent of its P, Zn and Cu, 50–80 per centof its Mg, N, Fe and Mn, 41–46 per cent of its S and Caand 11–21 per cent of its K and Na. Losses of nutrientsfrom capsules during fruit ripening were: Zn, 73 per cent, P,42 per cent, Cu, 23 per cent and Mn, 8 per cent. Dry matter,N, K, S, Ca, Mg, Na and Fe were not withdrawn from capsules.Apparent retranslocation from capsules could have provided from6–28 per cent of the Zn, Mn, P and Cu in mature seeds.Seeds from plants on poor sandy soil were small but had adequatelevels of nutrients when compared with those from plants growingon a fertile loam. Concentrations of all nutrients except P were higher in youngcapsules than in young seeds, but levels of N, P, Mg, Fe, Znand Cu were higher in mature seeds than in mature capsules.The intake of most nutrients by fruits was out of phase withdry matter accumulation, especially in capsules, and the elementsappeared to accumulate in fruit parts independently of eachother. Glutamine accounted for over 85 per cent of the amino-Nin phloem sap destined for fruits. Potassium made up over 90per cent of the inorganic cations in phloem exudate. Of theminor elements in the exudate, Fe was present at highest concentrationand Cu at the lowest. The results showed that retranslocation from the capsule madea very small contribution to the nutrition of seeds. It is suggestedthat R. communis would require a sustained supply of soil nutrientsto ensure maximum seed yield, partly due to the restricted retranslocationof most nutrients from capsules. Ricinus communis L., castor bean, mineral nutrition, translocation, retranslocation     

Seasonal Dynamics of the Accumulation, Distribution and Redistribution of Dry Matter and Mineral Nutrients in a Weedy Species of Gladiolus (Gladiolus caryophyllaceus)

The seasonal dynamics of the accumulation, distribution andredistribution of dry matter and 12 mineral nutrients by a weedyspecies of gladiolus (Gladiolus caryophyllaceus) were studiedat Perth, Western Australia, where it has colonized the nutrient-poorsandy soils. Parent corms sprouted in autumn, and the plantshad completed their growth cycle by early summer. The maturereplacement corm had 15-25% of the plant's P, Ca, Na, Zn andCu, 5-15% of its K, N, Cl, Mg, S and dry matter, and < 5%of its Fe and Mn. Seeds had 26% of the plant's dry matter, 60%of its N and P, 21-33% of its S, Mg, Cu and K, 5-20% of itsFe, Mn and Zn, and < 5% of its Ca and Na. The mature vegetativeshoot had 47% of the plant's dry matter and over 40% of eachnutrient, except for N, P and Cu. Phosphorus, K and N were redistributedfrom the parent corm with over 85% efficiency, S, Mg, Zn andCu with 60-70% efficiency, but there was < 10% redistributionof Ca, Na, Cl, Fe and Mn. The efficiency of redistribution fromthe leafy shoot was over 70% for N and P, 29-52% for K, Mg andCu, 16-20% for S, Zn and Cl, but negligible for Ca, Na, Fe andMn. Redistribution from the shoot could have provided the replacementcorm and seeds with 53-98% of their Cu, Mg, N, P and K, and29-38% of their S, Zn and dry matter. Seeds contained over 60%of each nutrient in a capsule, except for Ca, Na and Fe. Redistributionfrom the capsule walls could have provided 13-19% of the P,Cu and Zn, and 3-7% of the N, K, Mg and dry matter accumulatedby seeds. Each plant produced an average of 520 seeds. Removalof flowers and buds at first anthesis resulted in a larger replacementcorm containing a greater quantity of most nutrients, indicatingcompetition between the replacement corm and seeds for nutrients.Redistribution from parent to replacement cormlets in the absenceof shoot and root development was high, with over 50% of thedry matter and each nutrient, except for Ca, being transferred.Concentration of nutrients were low in all organs of G. caryophyllaceus,especially the replacement corm. It was concluded that the effectiveredistribution of key nutrients, such as N and P, to reproductivestructures and tolerance of low internal concentrations of nutrientscontribute to the capacity of G. caryophyllaceus to colonizeand persist on infertile soils.Copyright 1993, 1999 AcademicPress Gladiolus caryophyllaceus, corm, distribution, dry matter, gladiolus, mineral nutrients, nutrient accumulation, nutrient redistribution, seasonal growth, weed     

镁肥对马尾松幼苗生长与叶片元素积累的影响

为了探讨上杭种源马尾松Pinus massoniana叶营养与生长对不同镁肥水平的响应,以其优良种源1年生苗为材料,设置4个镁肥梯度(42 g·m-2、85 g·m-2、170 g·m-2、339 g·m-2),测定移栽1年后苗木生长指标及叶内营养含量。结果表明,施镁能够促进元素P、K、Ca、Fe、Cu、Zn积累,抑制N、Mg、Mn积累;镁施肥量为85 g·m-2时,对N、Mg、Mn积累的抑制作用不显著,对P、K、Ca、Fe、Cu、Zn积累的促进作用最大,苗木生长最好,为最佳施肥量。施镁并不能促进苗木对镁的吸收,而是改变了营养供应的土壤环境,从而改变植物对其他营养的吸收比例,进而影响植物的生长。苗木的生长与Fe、P、K的关系最为密切,其次是Mg、Mn、Ca、N、Cu、Zn。     

Accumulation, Partitioning and Redistribution of Dry Matter and Mineral Nutrients in Ixia flexuosa L., with Special Reference to its Cormaceous Habit

The seasonal dynamics of uptake, partitioning and redistributionof dry matter, N, P, K, S, Ca, Mg, Na, Cl, Fe, Zn, Mn and Cuby the cormaceous plant Ixia flexuosa were studied in pot cultureat Perth, Western Australia. Dry matter and P, N, K, Zn andCu were redistributed from the mother corm with about 90 percent net efficiency: there was no net redistribution of Ca,Na, Fe or Mn. The efficiency of redistribution from the leafyshoot to fruits and the new season's corm was 80 per cent forN and P, 24–49 per cent for K, Cu and Zn, and 0–15per cent for Na, Fe, Ca, Mn, Cl, Mg, S and dry matter. Redistributionfrom the mother corm and vegetative organs could have suppliedthe replacement corm, cormlets and fruits with 32–53 percent of their S, K, P, N, Cu and Zn, and 11–25 per centof their Ca, Cl, Mn, Mg and dry matter. The mature replacementcorm had over 60 per cent of the plant's N and P, 25–50per cent of its dry matter, Zn, Cu, Mg, K and Cl, but less than20 per cent of its Ca, Na, Fe and Mn. Each plant produced anaverage of 12 cormlets; these had 35 per cent of the dry matterand 23–47 per cent of the amount of a particular nutrientin the new season's corms. Fruits had less than 16 per centof the dry matter and each mineral in the mature plant. Ratesof mineral intake by Ixia were much lower than reported forcrop plants, and may be related to the long growing season ofthe species. Ixia polystachya L., corm, nutrition, mineral nutrients, nutrient redistribution     

Mobilization of Minerals to Developing Seeds of Legumes

The mineral nutrition of fruiting plants of Pisum sativum L.,Lupinus albus L. and Lupinus angustifolius L. is examined insand cultures supplying adequate and balanced amounts of essentialnutrients. Changes in content of specific minerals in leaves,pods, seed coat, and embryo are described. P, N and Zn tendto increase precociously in an organ relative to dry matteraccumulation, other elements more or less parallel with (K,Mn, Cu, Mg and Fe) or significantly behind (Ca and Na) dry weightincrease. Some 60–90 per cent of the N, P and K is lostfrom the leaf, pod and seed coat during senescence, versus 20–60per cent of the Mg, Zn, Mn, Fe and Cu and less than 20 per centof the Na and Ca. Mobilization returns from pods are estimatedto provide 4–39 per cent of the seeds' accumulations ofspecific minerals, compared with 4–27 per cent for testatransfer to the embryo. Endosperm minerals are of only minorsignificance in embryo nutrition. Comparisons of the mineral balance of plant parts of Lupinusspp. with that of stem xylem sap and fruit tip phloem sap supportthe view that leaves and pod are principal recipients of xylem-borneminerals and that export from these organs via phloem is themajor source of minerals to the seeds. Endosperm and embryodiffer substantially in mineral compostition from phloem sap,suggesting that selective uptake occurs from the translocationstream during seed development. Considerable differences are observed between species in mineralcomposition of plant organs and in the effectiveness of transferof specific minerals to the seeds Differences between speciesrelate principally to Ca, Na and certain trace elements.     

Distribution of N,P, K,Ca, Mg,S, Zn,Fe, Mn and Cu in groundnut

Summary Concentration of N, P, K, Ca, Mg and S in summer groundnut crop was higher than in kharif while Zn, Fe, Mn and Cu contents were higher in summer crop. Kernel's N, P and Zn; Leaflet's Ca and Mn; Stem's K and Fe; Root's S and Cu and Petiole's Mg contents were highest. Shell's N, P, K, Mg, S, Zn and Cu; Kernel's Ca, Fe and Mn contents were the least. N, P, K, S, Zn and Cu concentrations decreased linearly as the crop grew. Ca, Mg, Fe and Mn concentrations did not display any distinct pattern. Ca concentration was positively correlated with pod yield in both the seasons.     

The Effects of Copper Supply and Shading on Retranslocation of Copper from Mature Wheat Leaves

Plants of Gamenya wheat (Triticum aestivum L.) were grown inpots of a Cu-deficient sand at two levels of Cu (deficient andsufficient), and harvested on days 13, 22, 28 and 38. In 50per cent of the pots in each Cu treatment, the oldest leaf andleaf 2 of the main stem were shaded when they reached full expansion. The Cu content of the oldest leaf of Cu-sufficient, unshadedplants was high at day 13 and declined rapidly to day 38. Thatof Cu-deficient, unshaded plants was initially relatively lowand declined much more slowly, so that at day 38 it resembledthat of Cu-sufficient plants. Shading the oldest leaf acceleratedthe loss of its Cu in both Cu-deficient and Cu-sufficient plants.The effects of shading and of Cu supply on the loss of Cu fromthe oldest leaf paralleled their effects on the loss of N andchlorophyll. The results suggest that most of the Cu in theoldest leaf does not move out until the leaf senesces. In Cu-deficient plants retention of Cu by old green leaves accentuatedCu deficiency. The release of Cu, resulting from shading theold leaves of Cu-deficient plants, stimulated the growth ofnew leaves. In Cu-sufficient plants, shading depressed growth. copper, shading, retranslocation, wheat, Triticum aestivum L.     

Arbuscular mycorrhizas enhance nutrient uptake in different wheat genotypes at high salinity levels under field and greenhouse conditions

Since most experiments regarding the symbiosis between arbuscular mycorrhizal (AM) fungi and their host plants under salinity stress have been performed only under greenhouse conditions, this research work was also conducted under field conditions. The effects of three AM species including Glomus mosseae, G.?etunicatum and G.?intraradices on the nutrient uptake of different wheat cultivars (including Roshan, Kavir and Tabasi) under field and greenhouse (including Chamran and Line 9) conditions were determined. At field harvest, the concentrations of N, Ca, Mg, Fe, Cu, and Mn, and at greenhouse harvest, plant growth, root colonization and concentrations of different nutrients including N, K, P, Ca, Mg, Mn, Cu, Fe, Zn, Na and Cl were determined. The effects of wheat cultivars on the concentrations of N, Ca, and Mn, and of all nutrients were significant at field and greenhouse conditions, respectively. In both experiments, AM fungi significantly enhanced the concentrations of all nutrients including N, K, P, Ca, Mg, Mn, Cu, Fe, Zn, Na and Cl. The synergistic and enhancing effects of co-inoculation of AM species on plant growth and the inhibiting effect of AM species on Na(+) rather than on Cl(-) uptake under salinity are also among the important findings of this research work.     

三种苦苣苔对石灰土和红壤的适应性分析

为探讨苦苣苔科植物对其岩溶生境的适应性,该研究选取黄花牛耳朵(Primulina lutea)、紫花报春苣苔(Pri.purpurea)和桂林蛛毛苣苔(Paraboea guilinensis)三种苦苣苔科植物,将其栽种在石灰土及红壤两种不同类型的土壤中,观测记录其生长性状并对其叶片元素含量进行测定和比较。植株采集过程中,同时采集自然生境中三种苦苣苔科植物叶片及取样植物基部土壤,并对叶片及土壤元素的含量进行测定,作为今后苗圃试验的参照。结果表明:三种苦苣苔科植物在两种土壤上的生长状况及适应性具有差异,其在石灰土上生长良好,在红壤上生长较差;在两种不同土壤中,除N外,桂林蛛毛苣苔的叶片其他元素(P、K、Mn、Mg、Ca、Zn、Cu)差异极显著(P0.01);除P外,紫花报春苣苔的叶片其他元素(N、K、Mn、Mg、Ca、Zn、Cu)差异极显著(P0.01);除N、Cu、Ca外,黄花牛耳朵的叶片元素(P、K、Mn、Mg、Zn)差异极显著(P0.01);三种植物的叶片元素比值,除少数值没有差异外,大部分指标差异都极显著;对叶片元素与栽培土壤元素的相关性分析,发现植物叶片Mn元素与土壤中N、Ca、Mg、Zn、Mn、有机质含量等呈正相关,土壤P元素与叶片中N、P元素呈正相关,而与叶片中Zn元素呈负相关关系。在其他栽培条件一致的条件下,土壤因素及物种差别是造成黄花牛耳朵、紫花报春苣苔和桂林蛛毛苣苔适应性产生差异的主要原因。     

Under-storey Nutrient Content in an Age Sequence of Douglas-fir Stands

The nutrient concentrations and contents of the under-storeyspecies were estimated for a series of Pacific North-west Douglas-fir[Pseudotsuga menxiessii (Mirb.) Franco] stands ranging in agefrom 9 to 95 years. Analyses were carried out for ash, N, P,K, Ca, Mg, Mn, Fe, Zn and Na and significant differences innutrient concentrations were found to exist between species;species rejecting certain nutrients and accumulating others.General trends for mean concentrations of some nutrients areassociated with stand maturity in that ash, K and Mg decline,P and Mn increase and N and Ca reaches a peak at 20–30years and then declines. The nutrient contents (kg ha^–1)of the under-storey component of the stands are presented andtrends discussed. Mineral nutrient content, under-storey vegetation, Pseudotsuga menziessii stands, Douglas-fir     

Nutrient Accumulation in the Fruits of Two Species of Seagrass, Posidonia australis and Posidonia sinuosa

The accumulation is described of N, P, K, S, Ca, Mg, Na, Fe,Zn, Mn and Cu in the developing pericarp and seed of two speciesof seagrass. Both species showed essentially the same patterns,which resemble those of herbaceous terrestrial plants. Therewas a close relation between dry matter and nutrient accumulation.N, P, K, Fe, Zn, Mn and Cu accumulated in the fruit againstlarge concentration gradients, with discrimination against Na.Seeds accumulated N, P and trace elements to a greater extentthan pericarps and other plant parts; P was apparently retrievedfrom pericarps to a greater extent than other elements. Calculationswere made of the losses of these elements from seagrass meadowsin shed fruits. Posidonia spp., seagrass, nutrient accumulation in fruits     

Plant Seeds as Mineral Nutrient Resource for Seedlings--A Comparison of Plants from Calcareous and Silicate Soils

Mineral nutrients of seeds constitute a significant source ofessential elements to seedlings and developing individuals ofvascular plants. In spite of their potential ecological significance,seed nutrient pools have attracted little attention with respectto calcifuge–calcicole behaviour of plants. The objectivesof this study were, therefore, to compare concentrations of13 macro- and micronutrients (K, Rb, Mg, Ca, Mn, Fe, Co, Cu,Zn, Mo, B, P and S) in seeds and leaves of 35 mainly herbaceousvascular plant species growing on both limestone (calcareous)and silicate (non-calcareous) soils. Concentrations of Rb andCo in seeds of plants originating from limestone soils were,on average, about half of those from silicate soils. Concentrationsof Mn, Mg, Zn and P of seeds were, or tended to be, lower orslightly lower in limestone-soil plants, whereas mean Ca andMo concentrations were higher. Comparing seed and leaf concentrationsof the same species from limestone and silicate soils generallydemonstrated a high P enrichment ratio, but a particularly lowK enrichment ratio in seeds, valid for both types of soil. Itwas also apparent that Fe and Mn, micronutrients which are lessreadily solubilized and taken up by plants on limestone soils,had significantly higher seed:leaf concentration ratios in plantsfrom limestone than from silicate soils, whereas the oppositewas true for Ca. This indicates a ‘strategy’ tosatisfy the demand of seedlings for elements which are lessreadily available in the soil.Copyright 1998 Annals of BotanyCompany Seed, leaf, plant, nutrient, content, calcareous, silicate, acid, soil.     

暖温带地区主要树种叶片凋落物分解过程中主要元素释放的比较

应用分解网袋法对暖温带落叶阔叶林内分布较为优势的辽东栎（Quercus liaotungensis)、五角枫（Acermono)、蒙椴（Tilia mongolica)、糠椴（T.mandshurica)等4种植物叶片凋落物第一年的分解速率损失过程基本符合Olson的指数降解模型。4种凋落物的分解速率（凋落物的年重量损失）依次为五角枫＞糠椴＞蒙椴＞辽乐栎。N、P、Na、Fe、Cu、Mn在几种凋落物残留物中各自有不同程度的富集。C、K含量显著单调下降,其它几种元素含量变化不太规律。可以看出,元素的初始含量对其释放速率有很大影响,当微生物固持作用使C与其它元素比升高到某一阈值时,元素开始释放;初始含量较高的元素则从最初开始释放。高含量的木质素对元素的净释放有一定抑制作用,而在凋落物分解初期影响不大。     

Changes in the mineral composition of soybean xylem sap during monocarpic senescence and alterations by depodding

Evidence from earlier studies with explants (stem cutting with a leaf and a pod) indicates that a decline in the supply of mineral nutrients from the roots may prepare the leaves for induction of monocarpic senescence in soybean [ Glycine max (L.) Merrill cv. Anoka). In order to assess the changes in mineral flux from the root system, xylem sap was collected from a decapitated plant under 100 kPa pressure over 50 min. The sap volume yield declines after flowering starts, but increases during pod extension and then decreases again during podfill. The concentrations of K, Ca, Mg, P, S, Zn, Fe, Mn, Cu, Mo and Si rise and then fall during reproductive development, but the exact timing differs among the elements. In contrast, B, Al and Na concentrations show a slow rise initially with a large increase in late pod development. Depodding, which prevents the early death of the plant, inhibits the changes of some elements (K, Mg) but not others (Ca. Mg, P, S, Zn. Fe. Mn, B, Cu, Al), and it does not prevent the decrease in sap volume delivered. Inasmuch as the mineral concentration of xylem sap quantitatively reflects upward mineral flux, the supply of most minerals to the shoot declines, and this decrease seems to be an important factor in the preparatory phase of monocarpic senescence. The different minerals show different patterns of change, which indicate differences in the transport mechanisms and their regulation.     

Leaf nutrient dynamics and nutrient resorption: a comparison between larch plantations and adjacent secondary forests in Northeast China

Aims Conversion of secondary forests to pure larch plantations is a common management practice driven by the increasing demand for timber production in Northeast China, resulting in a reduction in soil nutrient availability after a certain number of years following conversion. Nutrient resorption prior to leaf senescence was related to soil fertility, an important nutrient conservation strategy for plants, being especially significant in nutrient-poor habitats. However, the seasonal dynamics of leaf nutrients and nutrient resorption in response to secondary forest conversion to larch plantations is not well understood.Methods A comparative experiment between larch plantations (Larix spp.) and adjacent secondary forests (dominant tree species including Quercus mongolica, Acer mono, Juglans mandshurica and Fraxinus rhynchophylla) was conducted. We examined the variations in leaf nutrient (macronutrients: N, P, K, Ca and Mg; micronutrients: Cu and Zn) concentrations of these tree species during the growing season from May to October in 2013. Nutrient resorption efficiency and proficiency were compared between Larix spp. and the broadleaved species in the secondary forests.Important findings Results show that the seasonal variation of nutrient concentrations in leaves generally exhibited two trends, one was a downward trend for N, P, K, Cu and Zn, and another was an upward trend for Ca and Mg. The variations in foliar nutrient concentrations were mainly controlled by the developmental stage of leaves rather than by tree species. Resorption of the observed seven elements varied among the five tree species during leaf senescence. Nutrient resorption efficiency varied 6–75% of N, P, K, Mg, Cu and Zn, while Ca was not retranslocated in the senescing leaves of all species, and Mg was not retranslocated in Larix spp. Generally, Larix spp. tended to be more efficient and proficient (higher than 6–30% and 2–271% of nutrient resorption efficiency and resorption proficiency, respectively) in resorbing nutrients than the broadleaved species in the secondary forests, indicating that larch plantations had higher leaf nutrient resorption and thus nutrient use efficiency. Compared with Larix spp., more nutrients would remain in the leaf litter of the secondary forests, indicating an advantage of secondary forests in sustaining soil fertility. In contrast, the larch plantation would reuse internal nutrients rather than lose nutrients with litter fall and thus produce a positive feedback to soil nutrient availability. In summary, our results suggest that conversion from secondary forests to pure larch plantations would alter nutrient cycling through a plant-mediated pathway.     

Micronutrient Deficiency Influences Plant Growth and Activities of Superoxide Dismutases in Narrow-leafed Lupins

The effect of copper (Cu), zinc (Zn) or manganese (Mn) deficiencyon the growth and activity of superoxide dismutase (SOD) formswas investigated in seedlings of narrow-leafed lupins (LupinusangustifoliusL.). Plants grown without Zn developed Zn deficiencysymptoms 24 d after sowing (DAS), and those grown without Mnshowed Mn deficiency symptoms 31 DAS. However, plants grownwithout Cu did not show visible leaf symptoms. Shoot dry weightwas decreased by Zn and Mn deficiency 24 DAS, and by Cu deficiency31 DAS. Soluble protein concentration was reduced considerablyby Zn deficiency 24 DAS, but was not affected by Cu deficiencyuntil 31 DAS. In contrast, soluble protein concentration inMn-deficient plants was higher than in control plants 31 DAS.Shoot concentration of micronutrients which were not suppliedto plants decreased significantly, with a simultaneous increasein concentration of one or more of the other nutrients analysed.The activities of total SOD, MnSOD and Cu/ZnSOD on a fresh weightbasis declined drastically in -Cu and -Zn plants 24 DAS. Onthe contrary, the activities of total SOD and Cu/ZnSOD on eithera fresh weight or soluble protein basis increased markedly in-Mn plants 24 DAS, and MnSOD activity increased significantlyin these plants 31 DAS. It was concluded that micronutrientdeficiency (Cu, Zn or Mn) altered the activities of SOD formsdepending on the kind and severity of the deficiency stress.Manipulation of the capacity of plants to tolerate oxidativestress may influence their capacity to tolerate micronutrientdeficiency.Copyright 1999 Annals of Botany Company. Copper,Lupinus angustifolius, manganese, deficiency, superoxide dismutase, zinc.     

Phloem and Xylem Transport in the Supply of Minerals to a Developing Legume (Lupinus albus L.) Fruit

The economy of carbon, nitrogen, water and mineral elementsin fruits of Lupinus albus L. was studied by measuring accumulationof these quantities in the developing fruit and estimating itstranspirational losses and CO₂ exchanges. Combining this informationwith data on levels of mineral elements in the xylem sap andphloem sap supplying the fruit, it was possible to test whethertransport based on mass inflow through xylem and phloem wouldaccount for the observed intake of elements. A model of transportbased on water and carbon intake suggested that vascular intakeduring the fruit's life matched the recorded increment for mineralsto within ± 15 per cent for N, Na, Zn, Fe and Cu, andto within ± 23 per cent for P, K and S. However, estimatedvascular intake of Ca, Mg and Mn accounted for less than one–thirdof the recorded intake by the fruit, inadequacy of vascularintake being especially great early in growth. Transport inphloem accounted for more than 80 per cent of the fruit's vascularintake of C, N and S, and 70–80 per cent of its P, K,Mg and Zn. Xylem contributed 68 per cent of the vascular inputof Ca, 59 per cent of the Na, and 34–38 per cent of theFe, Mn and Cu. Enclosure and darkening of fruits reduced levelsof Ca and Fe but increased levels of N, P, K and Zn in fruitdry matter relative to unenclosed, illuminated fruits. Resultswere related to previous observations on fruit functioning. Lupinus albus, legume fruit, mineral supply, phloem, xylem     

Imidacloprid‐induced transference effect on some elements in rice plants and the brown planthopper Nilaparvata lugens (Hemiptera: Delphacidae)

Abstract The widespread use of imidacloprid against insect pests has not only increased the rate of the development of target pest resistance but has also resulted in various negative effects on rice plants and Nilaparvata lugens resurgence. However, the effect of imidacloprid on elements in rice plants and the transference of these element changes between rice and N. lugens are currently poorly understood. The present study investigated changes of Cu, Fe, Mn, Zn, Ca, K, Mg and Na contents in rice plants following imidacloprid foliar sprays in the adult female of N. lugens that develops from nymphs that feed on treated plants and honeydew produced by females. The results indicated that imidacloprid foliar spray significantly increased Fe and K contents in leaf sheaths. Generally, Fe, Mn, K and Na contents in leaf blades were noticeably decreased, but Ca contents in leaf blades for 10 and 30 mg/kg imidacloprid treatments were significantly increased. The contents of most elements except K and Mg in the adult females and honeydew were significantly elevated. Multivariate statistical analysis showed that Fe, Mn and Na in leaf blades and Fe and Mn in leaf sheaths could be proportionally transferred to N. lugens. The relationship between most elements in adult female bodies and in the honeydew showed a positive correlation coefficient. There were significant differences in the contents of some elements in rice plants and N. lugens from different regions.     

Cold-induced changes in mineral content in leaves of Coffea spp. Identification of descriptors for tolerance assessment

Temperature and mineral nutrition are major environmental factors regulating plant growth and development. Yet, cold impact on mineral contents and the ability of the plants to perform changes in specific elements as a part of the acclimation process received little attention. Using five Coffea genotypes previously characterized concerning their cold sensitivity, a mineral analysis was performed considering macro (N, P, K, Ca, Mg, and S) and micro (Na, Fe, Mn, Zn, Cu, and B) nutrients in order to predict their importance in cold tolerance. The results showed a cold-induced dynamics of mineral nutrients in recently mature leaves. The less cold sensitive Icatu, and partially Catuaí, accumulated N, Ca, Mn, Cu, and Zn with potential implications in the maintenance of photosynthetic performance, the reinforcement of the antioxidative defense system, lipid metabolism, and the expression of cold regulated genes, thus constituting interesting traits to evaluate the cold acclimation ability. After a principal component analysis (PCA), N, Fe, Mn, and Cu were further confirmed as strong candidates for an early cold tolerance evaluation due to their dynamics and to specific roles in the activities of Cu/Zn-SOD (Cu), APX (Fe), and PSII (Mn).