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1.
Abstract

Estimating the nitrogen (N) status of plants as a function of their spectral response is a promising technique to diagnose and optimize N fertilization. An experiment was conducted in Jiquilpan (Michoacán, México) in which three N levels (0.3, 3, and 20 mM of NO3 ? in the irrigation water) were applied to strawberry (Fragaria vesca) in a randomized complete block design with three replicates. The spectral response of strawberry was measured at both the canopy and leaf level using individual wavebands as well as vegetation indices. Individual leaves were separated into three strata (young, mature, and old) and leaf dry matter, leaf area, and N content (% dry matter) were measured in each stratum. Leaf area, biomass, and N content differed significantly between strata. Leaf area, biomass, and N content in all strata were affected by N fertilization. At the canopy level, N content was highly correlated with green reflectance (R550) (r2=0.50) and red reflectance (R680) (r2=0.60) as well as the vegetation indices simple ratio (SR) (r2=0.56), normalized difference vegetation index (NDVI) (r2=0.56), and hyperspectral NDVI (HNDVI) (r2=0.56). For individual leaves, significant differences between strata were found with normalized total pigment to chlorophyll a ratio index (NPCI) and MERIS terrestrial chlorophyll index (MTCI) (p<0.001) as well as R550, photochemical reflectance index (PRI), red edge position (REP), and REP calculated using the MERIS satelite wavelengths (p<0.01). Relationships between spectral indices and N content at the leaf level were found with the youngest leaves only, with NPCI (p<0.01) and MTCI (p<0.05), whereas only R550 responded to N fertilization (p<0.05).  相似文献   

2.
The effects of silicon (Si) (0, 1, and 2 mM) and sodium chloride (NaCl) salinity (0, 20, and 40 mM) on the yield, photosynthesis, and ion content in strawberry grown in hydroponics were investigated. Salinity caused a reduction in leaf area and plant biomass, regardless of Si supplement. Leaf area in Si1Na20 treatment was 37% higher than that of Si0Na20 treatment. Salinity at 20 mM concentration had a 25% yield reduction in absence of Si, corresponding to no reduction in the yield in the presence of Si compared with the Si treatment without salinity. The highest reduction of photosynthetic rate (Pn) was observed in Si1Na40 treatment; however, in the presence of Si, there was no reduction in the Pn rate at 20 mM NaCl concentration. An obvious positive relationship was found between potassium/sodium (K/Na) and Pn rate. Within each Si concentration, the increased salinity increased Na concentration in the leaf tissue. However, when Si was supplied to the salinity treatments Na concentration was significantly lower than that of the similar treatments without Si. Supplement of Si to the nutrient solution increased the Si concentration in the roots, and old and young leaves. A clear negative relationship (r2 = 0.71) was found between Si and Na concentration in the leaves. Salinity (NaCl40) increased the proline level 2.5-fold in the absence of Si, corresponding to no changes the proline level in the presence of 1 mM Si concentration compared with the Si treatment without salinity. The salinity (40 mM) increased the electroleakage by 50% compared with 0 mM NaCl treatment in the absence of Si supplement. Findings from this study lead to the conclusion that Si supplement to the nutrient solution ameliorated the deleterious effect of salinity on the strawberry growth; these effects were attributed to an enhanced K/Na ratio and the reduction in Na content and electroleakage ability in the leaf tissue.  相似文献   

3.
Tolerance of gerbera (Gerbera jamesonii L.) to long-term sodium chloride (NaCl) salt stress was evaluated by subjecting plants to 0, 10, 20, 30 and 40 mM NaCl levels for ten weeks. Increased NaCl led to a significant decrease in leaf and stem biomass. Salt stress significantly affected sodium (Na+), potassium (K+) concentrations in leaves, stems and roots leading to sharp declines in K+/Na+ ratios. Magnesium concentrations in stems and roots also showed significant declines. Adverse effect of salt stress on chlorophyll content was also significant. Proline seemed less effective in osmotic adjustment under long-term high salt stress. Switching from vegetative to reproductive growth phase was crucial for certain physiological functions. Leaf Na+ concentration showed significant correlation with important traits. These data suggest that NaCl threshold level in irrigation water for gerbera is around 10 mM. Leaf fresh weight, chlorophyll content and leaf K+/Na+ ratio are promising indicators of salt-sensitivity of gerbera.  相似文献   

4.
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.  相似文献   

5.
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.  相似文献   

6.
The iron-manganese (Fe-Mn) disorder in marigold (Tagetes erecta L.) is related to high Mn and low magnesium (Mg) in leaves. Three solution-culture experiments with marigold were conducted in a greenhouse. One investigated Mn and the disorder. Based on dry matter production, 4.5 mg Mn/L was the toxicity concentration and gave 880 mg Mn g?1 dry weight in new leaves and 1200 in old leaves. Manganese above 4.5 mg L?1 produced bronzed speckles on leaves. A second experiment investigated Mg and the disorder. Based on dry matter production, 10 mg Mg L?1 was the deficiency concentration and gave 1.5% Mg in the shoots. Symptoms of Mg deficiency did not resemble those of the disorder. A third experiment investigated Mn and Mg. Leaf chlorosis appeared at 2.5 mg Mn L?1 with the lowest supply of Mg. These experiments suggest that Mn supply is related to the disorder but increasing Mg does not alleviate the problem.  相似文献   

7.
Investigations on translocation of magnesium (28Mg) in sunflower plants. 1. The translocation and retranslocation of Mg respectively 28Mg in sunflower plants of different age have been investigated. The focus of this investigation was on the influence of the composition of the uptake solution and the age of plants on the uptake of Mg respectively 28Mg through the roots or through the leaves and on Mg translocation (distribution). 2. After sunflower plants were grown in Mg-deficient 1/2-Hoagland solution Mg in the plants were redistributed. The Mg in the roots, stems, cotyledons, primary and secondary leaves was retranslocated to the youngest leaves. 3. In isolated, secondary-rooted sunflower shoots grown in Mg-deficient solution, plant Mg was retranslocated into the new roots and into the youngest shoots. 4. The 28Mg-uptake from the 0,2 mM MgSO4 solution was usually higher than from the 1/10-Hoagland solution. The composition of the uptake solution had little influence on the distribution of 28Mg. Independent of the age plants had the highest 28Mg content in the young and the lowest in the old leaves. 5. Root uptake of 28Mg resulted in a more uniform distribution in the plant than leaf uptake. The old leaves had a higher 28Mg content by root uptake than by leaf uptake of 28Mg. This is probably influenced by transpiration, in combination with the xylem transport of 28Mg after root uptake, which differs from leaf uptake and translocation in basipetal direction. 6. With increased age of plants, the content of 28Mg/10 gr. fresh weight decreased and the difference in content between the parts of plant was higher. The decrease of Mg content in the oldest leaves was the highest. 7. The results showed that Mg was transportable in the phloem. The magnitude and the direction of Mg transport was determined as primarily through the assimilation stream, which is coupled with Mg transport in plants.  相似文献   

8.
Plants of Norland potatoes (Solanum tuberosum L.) were maintained for 42 days at Mg concentrations of 0.05, 0.125, 0.25, 1, 2, and 4 mM in a nonrecirculating nutrient film system under controlled environment. With the increased Mg supply from 0.05 to 4 mM, Mg concentrations in the leaves of the 42-day old plants increased significantly from 1.1 to 11.2 mg g-1 dry weight. Plant leaf area and plant and tuber dry weights increased with increased Mg concentrations up to 1 mM in solution or 6.7 mg g-1 in leaves, and then decreased with further increases in Mg concentrations. Rates of CO2 assimilation measured on leaflets in situ at ambient and various intercellular CO2 concentrations were consistently lower at 0.05 and 4 mM Mg than at other Mg treatments, which may indicate decreased photosynthetic activity in mesophyll tissues at the lowest and highest Mg concentrations. Dark respiration rates in leaves were highest at 0.05 and 4 mM Mg, lowest at 0.25 and 1 mM Mg, and intermediate at 0.125 and 2 mM Mg. The different Mg treatments also influenced accumulation of other minerals in leaves. Leaf concentrations of Ca and Mn decreased with increased Mg supply except that Ca and Mn were lower at 0.05 mM than at 0.125 mM Mg. Leaf K concentrations were lower at 1, 2 and 4 mM Mg than at other Mg treatments. Foliar concentrations of P, Fe, Zn, and Cu had small but inconsistent variation with different Mg concentrations. Leaf concentrations of N, S, and B were similar at different Mg concentrations. This study demonstrates that various Mg nutrition, along with altered accumulation of other nutrients, could regulate dry matter production in potatoes by affecting not only leaf area but also leaf carbon dioxide assimilation and respiration.  相似文献   

9.
Four separate experiments were carried out in greenhouse conditions from spring of 2001 to summer of 2003. The aim of this research was to study the effect of factors such as leaf age, salt type and concentration, number of foliar applications, and the nutritional status on the efficiency of foliar applications of potassium (K) in olive plants. In all experiments, mist-rooted ‘Picual’ olive plants growing in 2 L pots containing perlite were fertigated with a complete nutrient solution containing 0.05 mM or 2.5 mM potassium chloride (KCl). In one experiment, plants received two foliar applications with five concentrations of KCl (0%, 2%, 4%, 6%, or 8%) at 63 and 84 days after transplanting. Foliar KCl applications at 2% or 4% increased shoot lengths and the K content of plants fertigated with 0.05 mM KCl (poor K nourished), while foliar KCl application did not have any influence on the growth or K content of plants fertigated with 2.5 mM KCl (normal K nourished). When the number of foliar applications was increased, the results showed that two foliar applications were enough to increase leaf K concentration in olive plants above the sufficiency level. Leaf age could influence the efficiency of foliar K application. Leaf K concentration were higher in young leaves than in mature ones. All K-salts studied as foliar sprays [KCl, potassium sulfate (K2SO4), potassium nitrate (KNO3), potassium carbonate (K2CO3), and potassium phosphate (KH2PO4)] were effective in increasing leaf K concentration. The results obtained in the present study indicate that foliar applications of K effectively increase K content in K-deficient olive plants, and that foliar applications might be more effective on young leaves. Two foliar applications of 4% KCl or the equivalent for other salts are enough to increase leaf K concentration.  相似文献   

10.
The objective of this research was to study the effects of nitrogen (N) forms (NO3–, 2.6 mM; NH4+, 2.6 mM; NO3–, 1 mM + NH4+, 1.6 mM) on the growth and mineral composition of kiwifruit plants exposed to three boron (B) levels (0.025, 0.1, 0.3 mM). The kiwifruit plants were grown in a 1:1 sand : perlite mixture and irrigated daily with nutrient solutions. Shoot height, mean shoot dry weight, the number of leaves, mean leaf dry weight, and N concentration of NH4‐treated plants were significantly higher compared to the NO3– treatment at all B levels. The concentration of 0.3 mM B significantly reduced shoot height for all N treatments. Boron toxicity symptoms appeared 14 days after starting the experiment, when plants were treated with 0.1 and/or 0.3 mM B. The nitrate supply reduced the B concentration of roots, but B levels of different leaf parts were hardly affected by the N form. Furthermore, the NH4‐N form significantly reduced the Mg concentration of the leaves.  相似文献   

11.
In separate tests, rabbiteye blueberries (Vaccinium ashei Reade) grown in sand culture were subjected to varying levels of Ca (0–81 mg/liter) and Mg (0–24 mg/liter) applied at rates of 250 ml/plant daily. Other essential nutrients were kept constant. Leaf concentrations of N, P, K, Mg, Ca, Mn, Fe, Cu, B, Zn, Co, and Al were determined. The concentration of Ca in the leaves increased linearly but that of Cu decreased in response to increasing levels of Ca fertilization. Leaf concentrations of other elements were not significantly influenced by Ca fertilization. Leaf Mg and Al concentrations increased linearly in response to increasing levels of Mg fertilization. The P content in leaves followed a quadratic curve with increased Mg fertilization. Percent P increased from the 0 to 12 mg/liter levels and then decreased from the 12 to 24 mg/liter levels of Mg. High levels of Mg fertilization resulted in reduced Cu content of leaves.

Fertilization rates of Ca or Mg had little effect on shoot dry weight except at the 0 mg/liter levels. As leaf Ca decreased below 0.20% Ca, Ca deficiency symptoms became more prevalent. Magnesium deficiency symptoms increased as leaf Mg decreased below 0.15% Mg.  相似文献   


12.
To examine tolerance of cadmium (Cd) by eggplant (Solanum melongena L.) cv. ‘Hybrid PK 123’, plants were grown in refined sand in complete nutrient solution for 52 days in a glasshouse at ambient temperature. Cadmium sulfate was superimposed on day 53, at variable levels: nil, 0.05, 0.1, 0.2, 0.4, and 0.5 mM. Influence of excess Cd was discernible after 5 days of metal supply at 0.4 and 0.5 mM Cd as depression in growth. At these levels, foliar symptoms were initiated as paling of young leaves at the base progressing upward. With increase in age, affected leaves turned golden yellow and these effects spread to lower leaves. Leaf size and floral initiation were very much restricted. These types of phenotypes induced leaf senescence. Excess Cd reduced the biomass and fruit yield of plants. At higher levels (>0.1 mM) of Cd, fruit formation was completely inhibited and fruits formed at 0.05 and 0.1 mM Cd were smaller in size. Besides this, excess Cd disturbed the metabolism of eggplant by reducing the concentration of chlorophyll (a and b), protein, Hill reaction activity, and activity of antioxidant enzymes—catalase and ascorbate peroxidase; whereas the activity of peroxidase and ribonuclease increased in leaves of eggplant. Cadmium excess reduced the concentration of Fe and Zn and Cd increased that of proline, lipid peroxidation, phenols, reducing sugars and Cd concentration in leaves of eggplant.  相似文献   

13.
ABSTRACT

The present work was aimed at determining the limits of tolerance to sodium chloride (NaCl) of a halophyte, Beta macrocarpa Guss (wild Swiss chard). Five week-old plants were cultivated with a nutritive solution to which was added 0, 100, 200, and 300 mM NaCl. Plants were harvested after four weeks of treatment. The growth (fresh and dry weight, leaf surface area, and leaf number), water contents, and the mineral composition (meq · g?1 DW) of roots and leaves (reduced nitrogen (N), K+, Ca2 +, Na+, Cl?) were determined on individual plants. Results show that Beta macrocarpa can tolerate up to 200 mM NaCl. A significant decrease in biomass production (to 50% of control) was observed only for 300 mM NaCl. In the latter treatment, leaf mean surface area was 25% of control. The shoot-to-root ratio was not changed. Leaf hydration was not modified by salt treatment. This ability of the plant to maintain the hydric equilibrium of its leaves seemed associated with an efficient intracellular compartmentalization of Na+ and Cl? ions. Salt treatment had little effect on N content (80% of control), but decreased significantly K+ and Ca2 + contents. These three essential elements could be limiting for growth of leaves and roots of plants challenged by NaCl.  相似文献   

14.
Magnesium (Mg) deficiency reduces yield and quality of crops as Mg is involved in carbohydrate and protein anabolism. Foliar application of MgSO4 represents a means of ameliorating the nutritional status of crops growing under conditions of deficiency. Foliar Mg application has been demonstrated to increase the chlorophyll concentration and vegetative yield of plants. However, in crop plants used for seed production, the limited number of available studies provides only conflicting results in terms of the efficiency of Mg leaf application on yield and quality. We have examined the effect of increasing Mg foliar application rates on differentially developed leaves and leaf stages with regards to Mg concentration, chlorophyll concentration and biomass formation. Our data reveal that in order to obtain significant effects MgSO4 concentrations in the spraying solution should be higher than 50 mM, as lower concentrations did not lead to significant changes in the vegetative or generative material. Positive effects of the foliar application on chlorophyll concentration and leaf area were only measured in leaves treated with 200 mM foliar MgSO4. The application of Mg did not affect the parameters chlorophyll, ion concentration and leaf area in the newly developing leaves, but it had an important influence with regard to yield traits, especially on the formation of pods. The quality of the seeds with regard to the protein concentration was reduced in response to the magnesium deficiency treatment, but the application of foliar magnesium prevented a significant loss of protein.  相似文献   

15.
  【目的】  对比大、中量养分短期缺乏下脐橙新、老叶片中11种必需元素含量及变化,并分析缺素导致的营养元素间的相互影响。  【方法】  以一年生枳砧纽荷尔脐橙幼苗为试材进行了砂培试验。以完全营养液为对照 (CK),设置缺氮 (?N)、缺磷 (?P)、缺钾 (?K)、缺钙 (?Ca)和缺镁 (?Mg)处理,测定不同处理脐橙叶片（老叶和新叶）生长指标及矿质元素含量。  【结果】  所有缺素处理均导致叶片叶绿素含量降低,生物量减少,以缺氮处理最为显著。缺氮降低了叶片N、Ca、Cu、Mo含量;缺磷降低了叶片P、K、Mo含量;缺钾降低了叶片K含量;缺钙降低了叶片N、Cu、Zn、Mo含量但增加了P含量;缺镁降低了叶片Ca、Mg、Zn、Mo含量但增加了K含量。以必需矿质元素为变量分别对各处理老叶和新叶进行主成分分析,老叶中第一主成分 (PC1)明显将缺钾处理与其他处理区分开,与对照相比,缺钾老叶离子组成变化为N (?3%)、P (+1%)、K (?71%)、Ca (+11%)、Mg (+39%)、B (+16%)、Mn (+11%)、Fe (+32%)、Cu (?7%)、Zn (+14%)、Mo (?63%);新叶中PC1明显将缺氮处理与其他处理区分开,缺氮新叶离子组成变化为N (?53%)、P (+8%)、K (+7%)、Ca (?14%)、Mg (+11%)、B (+55%)、Mn (+51%)、Fe (?14%)、Cu (?57%)、Zn (+4%)、Mo (?25%)。老叶和新叶中元素含量呈正相关的元素是N-Cu、N-Ca、Mg-Mn和Cu-Mo,呈负相关的是K-Zn。  【结论】  脐橙幼苗老叶对钾的短期缺乏反应最敏感,缺钾会显著降低老叶中K和Mo含量并增加Mg和Fe含量,而新叶对氮素的短期缺乏最敏感,缺氮显著降低新叶中N、Ca、Cu和Mo含量。短期缺少P、Ca和Mg对脐橙幼苗叶片中的养分含量影响较小。  相似文献   

16.
以3 个芭蕉芋栽培品种为试材,研究了芭蕉芋发棵结芋期和子芋完熟期生物量的构成特点及各器官矿质元素含量、 积累和分配规律,以期为芭蕉芋科学管理和合理施肥提供依据。结果表明,发棵结芋期,芭蕉芋干物质量为54.99~62.21g/plant,叶片是干物质主要的分配器官; 子芋完熟期,芭蕉芋的干物质量是发棵结芋期的 4 倍多,根茎为干物质的主要分配器官。发棵结芋期,3 个芭蕉芋品种平均每株累积吸收N 497.4mg~598.8mg、 P 128.7mg~223.1mg、 K 2021.2.mg~2450.3mg、 Ca 496.0 mg~577.3 mg、 Mg 526.7 mg~804.5 mg,氮以叶片中含量最高,磷、 钾和镁以茎中含量最高,根系内钙含量最高; 子芋完熟期,芭蕉芋平均每株累积N 1116.2~1210.8mg、 P 852.6~907.5mg、 K 4528.9~5055.2 mg、 Ca 919.2~991.7mg、 Mg 888.2~1369.0 mg,氮以叶片含量最高,钾含量以根系最高,磷含量以茎、 叶中最高,根茎内镁含量高。生育期内构建相同生物量,Xingyu-1需要的 K、 Ca 和 Mg 比其他 2个品种多,N和P与其他2个品种相当,但Xingyu-1 的根茎干物质分配率高,生产相同质量的干根茎,Xingyu-1 需要的N、 P、 K 低于其他 2 个品种。  相似文献   

17.
Abstract

The present study was conducted in the existing germplasm block of gerbera under protected condition at ICAR-IIHR, Bengaluru, India during 2017–2019 to obtain comprehensive information on biomass partitioning, nutrient uptake pattern and flower yields in different genotypes for precision use of critical inputs. The number of leaves (187.6–353.2 m?2?yr?1) and flower stalks (166.9–274.5 m?2?yr?1) varied significantly among genotypes. Specific leaf area (SLA) was similar among Balance, Stanza, Arka Aswha and Terra Kalina cultivars (0.150–0.156?cm2 mg?1). Strong positive influence of SLA on number of flower stalks was evident from the significant correlation (r = –0.774). Significant positive correlations among number of flower stalks and leaves, leaf area and SLA substantiate the flower yield pattern in gerbera. Optimum leaf number per plant was estimated at 18.6, while optimum range was quantified at 14.1 to 22.4. In gerbera genotypes, the partitioning of total aboveground dry biomass to leaves and flower stalks was 46–61% and 39–54%, respectively. The average nutrient removal was quantified at 32.8?g N, 7.3?g P, 78.7?g K, 24.7?g Ca and 4.1?g Mg m?2?yr?1 and the uptake of macronutrients was in the order of K?>?N > Ca > P?>?Mg. The order of micronutrient removal (g m?2?yr?1) was Fe (0.2), Zn (0.08), Mn (0.06) and Cu (0.03). The soil fertility status at uniform management was above optimum. It is clear that leaf number, biomass partitioning and nutrient removal pattern had direct impact on flower stalk yields of gerbera.  相似文献   

18.
Crop production in many parts of the world is increasingly affected by soil salinization, especially in the irrigated fields of arid and semi-arid regions. The effects of four magnesium levels [0, 0.5, 1, and 22 millliMolar (mM) magnesium as magnesium sulfate (MgSO4.5H2O)], and three salinity levels [0, 45 and 90 mM sodium chloride (NaCl)] on growth and the chemical composition of pistachio seedlings (Pistacia vera L.) cv. ‘Badami-e-Zarand’ was studied in sand culture under greenhouse conditions. The experiment was set up as a completely randomized design (CRD) with four replications. After 28 weeks the growth parameters of biomass, leaf number, leaf area and stem height were measured. The results demonstrated that salinity decreased biomass, leaf area and stem height; the application of 2 mM magnesium (Mg) significantly reduced biomass, leaf number, leaf area and stem height; salinity stress increased concentrations of sodium (Na) and potassium (K) in shoot as well as Na concentration in root; however, it decreased Mg and calcium (Ca) concentrations in shoot, as well as Mg, Ca, and K concentrations in root. The application of 2 mM Mg reduced K and Ca concentrations in shoot and Na and K concentrations in root.  相似文献   

19.
Greenhouse grown ‘Golden Delicious’ apple seedlings were treated with soil drenches of paclobutrazol (PP333) at rates equivalent to 0.1, 0.2, 0.4, 0.8, and 1.6 kg of active ingredient (a.i.) ha.‐1 Eleven weeks after treatment initiation, seedlings were harvested, divided into leaves, stems, and roots, weighed and analyzed for the content of macro‐and microelements. Shoot growth rate, leaf area, and total dry weight showed a decreasing trend with increasing rates of PP333. In contrast, specific leaf weight increased in response to growth regulator treatments. The total amount of N, Zn, and Cu absorbed by seedlings was not affected and that of K, Ca, Mg, and Mn was decreased by PP333 treatments. Concentration of Ca and Mn in leaves, N in roots, and N, Ca, Mg, Mn, Zn, and Cu in stems increased in response to PP333 treatments. The magnitude of these increases were dependent on the rate of growth regulator applied. Potassium was the only element which declined in concentration in leaves and stems; this was true, however, only at the two highest rates of PP333 (0.8 and 1.6 kg ha‐1) Root K concentration was not affected by PP333 treatments.  相似文献   

20.
Abstract

Sodium (Na) movement between plants and humans is one of the more critical aspects of bioregenerative systems of life support, which NASA is studying for the establishment of long‐term bases on the Lunar or Martian surface. This study was conducted to determine the extent to which Na can replace potassium (K) in red beet (Beta vulgaris L. ssp vulgaris) without adversely affecting metabolic functions such as water relations, photosynthetic rates, and thus growth. Two cultivars, Ruby Queen and Klein Bol, were grown for 42 days at 1200 μmol mol?1 CO2 in a growth chamber using a re‐circulating nutrient film technique with 0%, 75%, 95%, and 98% Na substitution for K in a modified half‐strength Hoagland solution. Total biomass of Ruby Queen was greatest at 95% Na substitution and equal at 0% and 98% Na substitution. For Klein Bol, there was a 75% reduction in total biomass at 98% Na substitution. Nearly 95% of the total plant K was replaced with Na at 98% Na substitution in both cultivars. Potassium concentrations in leaves decreased from 120 g kg?1 dwt in 0% Na substitution to 3.5 g kg?1 dwt at 98% Na substitution. Leaf chlorophyll concentration, photosynthetic rate, and osmotic potential were not affected in either cultivar by Na substitution for K. Leaf glycinebetaine levels were doubled at 75% Na substitution in Klein Bol, but decreased at higher levels of Na substitution. For Ruby Queen, glycinebetaine levels in leaf increased with the first increase of Na levels and were maintained at the higher Na levels. These results indicate that in some cultivars of red beet, 95% of the normal tissue K can be replaced by Na without a reduction in growth.  相似文献   

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