Nifedipine influence on mineral nutrient uptake by sorghum primary root tips

Seedling sorghum [Sorghum bicolor (L.) Moench. cv GP‐10, SC283, SC574, and Funk G522DR] primary root tips (1‐cm) content of calcium (Ca), phosphorus (P), zinc (Zn), boron (B), manganese (Mn), iron (Fe), magnesium (Mg), and copper (Cu) in response to a Ca²⁺‐channel blocker (nifedipine 0, 0.01, 0.1, or 1 μM) was measured after a 1‐hr exposure to Hoagland and Arnon complete mineral nutrient solution. Content of ions was significantly different among the cultivars. Responses to nifedipine were element‐cultivar‐blocker concentration dependent.     

Vanadate influence on calcium (45Ca2+) absorption by sorghum root tips

One‐cm root‐tips of Sorghum bicolor (L.) Moench cv Funk G522DR, SC574, SC283, or GP‐10 were exposed to calcium (⁴⁵Ca²⁺) for 2‐hr at pH 5.5 in the presence of vanadate (0,0.1, 1.0, or 10.0 mM). Genetic variation in vanadate‐untreated absorption of ⁴⁵Ca²⁺ was observed. Vanadate inhibited ⁴⁵Ca²⁺ uptake in Funk G522DR, SC574, and GP‐10 linearly with the log concentration. In SC283, 0.1 mM vanadate significantly decreased ⁴⁵Ca²⁺ absorption; but, ⁴⁵Ca²⁺ absorption increased at higher vanadate concentrations.     

Magnesium influence on calcium (45Ca2+) absorption by sorghum root tips

Influence of magnesium sulfate (MgSO₄ ‐ 0, 0.01, 0.1, or 1.0 mM) on absorption of calcium as ⁴⁵Ca²⁺ in 2‐hr exposures at pH 5.5 by 1‐cm root‐tips of Sorghum bicolor (L.) Moench. cv SC574, SC283, GP‐10, and Funk G522DR was undertaken. Magnesium (0.01 mM) induced a significantly increased and 1.0 mM induced a significantly decreased ⁴⁵Ca²⁺ uptake.     

Malachite green influence on calcium (45Ca2+) absorption by sorghum root tips

Malachite green (MG) [N‐[4‐[[4‐dimethylamino)phenyl] phenyl‐methylene]‐2,5‐cyclohexadien‐l‐yl idene] ‐N‐methyl‐methanarninium chloride] (0, 0.1, 0.2, 0.4, 0.6, 0.8, 1.0 mM) was evaluated for influence on calcium (⁴⁵Ca²⁺) absorption by 1‐cm root‐tips of sorghum [Sorghum bicolor (L.) Moench. cv GP‐10, SC283, SC574, and Funk G522DR]. Calcium (⁴⁵Ca²⁺) absorption was significantly decreased in all four cultivars at 0.1 mM. LD₅₀’s were Funk G522DR (0.15 mM), GP10 (0.25 mM), SC283 (0.30 mM), and SC574 (0.31 mM).     

Diltiazem influence on calcium and aluminum absorption by roots of three sorghum cultivars

Calcium (Ca⁺⁺) (10 mM) and Al⁺⁺⁺ (10 mM) ions were applied unilaterally in agar to primary roots of sorghum [Sorghum bicolor (L.) Moench.]. Both Ca⁺⁺ and Al⁺⁺⁺ caused unilateral growth “inhibitions and induced root curvature in cv Funk G522DR, SC574, and SC283 (acid soil stress sensitive, tolerant, and tolerant, respectively). Diltiazem (0.1 mM) [3‐(acetyloxy)‐5‐[2‐(dimethylamino)ethyl]‐2,3‐dihydro‐2‐(4‐methoxyphenyl)‐l‐5‐benzothiozepin‐4 (5H)‐one] inhibited Ca⁺⁺ absorption in Funk G522DR and SC283 but only partially influenced Ca⁺⁺ absorption by roots of SC574. Aluminum ion absorption by roots was inhibited in SC283 and SC574 but not in Funk G522DR.     

Nitrate/ammonium ratio effects on mineral element uptake by sorghum 1

Abstract

Experiments were conducted using different NO₃ ^–/NH₄ ⁺ ratios to determine the effects of these sources of N on mineral element uptake by sorghum [Sorghum bicolor (L.) Moench] plants grown in nutrient solution. The NO₃ ^–/NH₄ ⁺ ratios in nutrient solution were 200/0, 195/5, 190/10, and 160/40 mg N L^–1. Nutrient solutions were sampled daily and plants harvested every other day during the 12‐day treatment period.

Moderately severe Fe deficiencies were observed on leaves of plants grown with 200/0 NO₃ ^–/NH₄ ⁺ solutions, but not on the leaves of plants grown with the other NO₃ ^–/NH₄ ⁺ ratios. As plants aged, less Fe, Mn, and Cu were translocated from the roots to leaves and leaf/root ratios of these elements decreased dramatically in plants grown with 200/0 NO₃ ^–/NH₄ ⁺ solutions. Extensive amounts of Fe, Mn, and Cu accumulated in or on the roots of plants grown with 200/0 NO₃ ^–/NH₄ ⁺ solutions. Manganese and Cu may have interacted strongly with Fe to inhibit Fe translocation to leaves and to induce Fe deficiency. As the proportion of NH₄ ⁺ in solution increased, K, Ca, Mg, Mn, and Zn concentrations decreased in the leaves, and Ca, Mg, Mn, and Cu concentrations decreased in roots. Potassium and Zn tended to increase in roots as NH₄ ⁺ in solution increased.     

不同养分配比对高粱根系生长及养分吸收的影响

为探明高粱养分吸收和根系生长对氮、磷、钾胁迫的响应,通过长期定位试验,在高粱/玉米轮作条件下研究了不同养分配比NPK、PK、NK、NP、CK对高粱根系生长及养分吸收的影响。结果表明:与NPK相比,长期不施氮肥(PK)条件下高粱总根长增加18.29%,总根体积降低26.52%,且根系主要分布在0~10 cm土层,直径小于0.5 mm细根所占比例显著增加。不施磷肥(NK)显著抑制了高粱根系生长,总根长、总根表面积和总根体积分别降低24.03%、27.48%和41.29%。不施钾肥(NP)对细根生长有明显抑制作用。不施氮、磷、钾均降低高粱对相应养分的吸收和累积,不施氮促进了营养器官中氮和钾素向籽粒转运,不施磷或钾肥抑制了氮、磷及钾的转运。高粱对养分的吸收、积累和转运与根系形态有关,不同养分积累与运转与根系形态关系表现不尽相同:氮素、钾素积累和转运与根系形态具有较好的相关性,氮素的积累和转运与植株生物量和产量的相关性大于磷素和钾素。综上,高粱根系形态及养分吸收对氮、磷及钾胁迫响应不同,该研究可为不同养分瘠薄地高粱高效栽培提供理论依据。     

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.     

Effects of excess manganese on mineral uptake in mycorrhizal sorghum

Associations between vesicular‐arbuscular mycorrhizal (VAM) fungi and manganese (Mn) nutrition/toxicity are not clear. This study was conducted to determine the effects of excess levels of Mn on mineral nutrient uptake in shoots and roots of mycorrhizal (+VAM) and non‐mycorrhizal (‐VAM) sorghum [Sorghum bicolor (L) Moench, cv. NB9040]. Plants colonized with and without two VAM isolates [Glomus intraradices UT143–2 (UT1 43) and Gl. etunicatum UT316A‐2 (UT316)] were grown in sand irrigated with nutrient solution at pH 4.8 containing 0, 270, 540, and 1080 μM of added Mn (as manganese chloride) above the basal solution (18 μM). Shoot and root dry matter followed the sequence of UT316 > UT143 > ‐VAM, and shoots had greater differences than roots. Shoot and root concentrations and contents of Mn, phosphorus (P), sulfur (S), potassium (K), calcium (Ca), magnesium (Mg), iron (Fe), zinc (Zn), and copper (Cu were determined. The +VAM plants generally had higher mineral nutrient concentrations and contents than ‐VAM plants, although ‐VAM plants had higher concentrations and contents of some minerals than +VAM plants at some Mn levels. Plants colonized with UT143 had higher concentrations of shoot P, Ca, Zn, and Cu and higher root Mg, Zn, and Cu than UT316 colonized plants, while UT316 colonized plants had higher shoot and root K concentrations than UT143 colonized plants. These results showed that VAM isolates differ in enhancement of mineral nutrient uptake by sorghum.     

Plant mineral contents of root tips from four sorghum cultivars after exposure to the anion channel blocker,sits

SITS (0, 0.01, 0.1, or 1.0 mM) influence on the absorption (1 hr) by 1‐cm root tips of Sorghum bicolor (L.) Moench cv GP‐10, SC 283, SC 574, or Funk G522DR seedlings of calcium (Ca), boron (B), phosphorus (P), zinc (Zn), manganese (Mn), iron (Fe), magnesium (Mg), and copper (Cu) from an Hoagland and Arnon complete mineral nutrient solution was evaluated by inductively coupled plasma emission spectrophotometry (ICP). Cultivar variation in response to SITS within each element was found. Multiple mechanisms of control for the absorption of each element among cultivars were evident.     

Calcium (45Ca2+) efflux from sorghum root tips

Sorghum [Sorghum bicolor (L.) Moench. cv GP‐10] root tips (1‐cm) were exposed to ⁴⁵Ca²⁺ for 1 hr. Root tips were washed in 0.01M EDTA for 5, 10, 15, 30, and 60 min. Calcium (⁴⁵Ca²⁺) remaining in the roots decreased on a T_1/2 = 12–13 minutes scale, which represents Ca²⁺‐ATPase activity in the GP‐10 root tips (1‐cm).     

Growth and nutrient uptake in grain sorghum grown under mulch

Mulches can alter plant growth by changing the soil environment, but their effects on mineral uptake in grain sorghum are unknown. A 3‐year study was conducted to measure nutrient uptake in plants grown under 0, 2200, 4400, and 8800 kg/ha mulch. Plants were irrigated to insure that moisture was not limiting. Dry‐matter production, total mineral uptake and concentrations were determined at 7‐ to 9‐leaf, late boot, soft dough, and physiological maturity growth stages. Mulches altered sorghum growth by delaying plant maturity and by increasing dry‐matter yields. Nutrient uptake increased with increased dry‐matter production although elemental concentrations declined. Hybrid reaction to mineral uptake was dependent on the specific environment created by the mulch. Hybrids did not respond the same to given mulch rates each year. Management considerations for soil fertility under mulch conditions should be made on the basis of expected dry‐matter yields for the specific environment.     

柚木优良无性系根系养分吸收动力学研究

以4个柚木优良无性系1年生苗木为试材,采用营养液培养和离子消耗曲线模拟方法,测定了根系的Ca2+、Mg2+、K+、NO-3吸收动力学参数。结果表明,以根系总吸收面积和总干重计算的Ca2+、Mg2+、K+、NO3-最大吸收速率相接近。在Ca2+、Mg2+、K+、NO3-最大吸收速率(Vmax)及离子流入速率(α值)指标上,不同基因型之间差异较大,而在养分离子吸收亲合力(Km)指标上,则没有明显差异。缅甸种源无性系VI-23根系对Ca2+、Mg2+、NO3-的Vmax及α值均为最大,而印度种源无性系70-12根系则对K+的Vmax及α值为最大,表明缅甸种源无性系VI-23为Ca、Mg和NO3--N硝态氮高效吸收基因型,印度种源无性系70-12为钾高效吸收基因型。     

Selectivity of the root absorption of nutrient ions in grain sorghum

Root absorption selectivity, which refers to the fact that the mineral elements are not found in the same proportions in the plant as in the growth medium, was characterized using plots where the proportions between the elements were considered. Grain sorghum was grown hydroponically in nutrient solutions where the cationic macroelements were increasingly replaced with sodium and the anionic macronutrients with chloride. The data obtained from the analyses of the nutrient solutions and of the whole plants show that root selectivity promotes the absorption of K⁺ and NO₃ ^‐ ‐N and impedes that of Ca⁺⁺ whereas there is nearly no selectivity towards the other nutrients (Mg, P, S).The high negative selectivity towards unessential elements (Na and Cl) is reflected by their very low proportions within the plant.

The comparison between the various plant organs shows that the proportions of the essential elements are nearly identical in the roots, the sheaths, the younger leaves and in the adult leaves (only for the anions). The differences observed for the older leaves are to be assigned to their senescence status which conditions the possibilities of translocation of the elements within the plant.     

矿质养分和激素对根毛生长发育的影响及作用机制

【目的】植物矿质养分和水分的吸收利用赖于根系,根系中根毛的生长发育不仅扩大了根系吸收表面积,促进了矿质养分和水分的吸收还有助于植物根的固定以及与土壤微生物的互作。本文从矿质养分角度(氮、 磷、 钾、 钙、 铁)和激素角度(生长素、 乙烯、 茉莉酸、 独脚金内酯、 油菜素内酯)探讨影响根毛生长发育的因子及作用机理。【主要进展】氮对根毛生长发育的影响与茉莉酸和乙烯有关, 磷与生长素、 乙烯、 独脚金内酯互作调控根毛生长发育;生长素和乙烯以交互作用调控根毛生长发育,茉莉酸、 独角金内酯和油菜素甾醇对根毛生长发育的作用是部分依赖生长素或乙烯途径;植物体内生长素和乙烯等激素的平衡对根毛的生长发育起着重要作用。【建议和展望】基于以上分析,从蛋白激酶及其相关调控基因及转录因子等方面可深入探析矿质养分、 植物激素等对根毛和丛枝菌根生长发育的影响。     

Soil temperature affects element uptake by sorghum

The influence of soil temperature on nutrient accumulation in aerial portions of sorghum plants was evaluated in a greenhouse experiment. Plants were grown in 20‐liter containers at cooled and ambient soil temperatures of 20 and 25C, respectively, and were harvested at the 8‐ and 12‐leaf stages of development for yield and nutrient analysis.

At the 8‐leaf stage, sorghum plants subjected to 25C were significantly higher in concentration of N, P, K, Mg, and Cu, but were significantly lower in Ca. Soil temperature did not significantly affect concentration of Zn, Fe, and Mn. At the 12‐leaf stage, sorghum plants grown in the warm soil temperature treatment were lower in concentration of N, K, Ca, Mg, Zn, Fe, Mn, and Cu than plants grown in the cooled‐soil treatment. Phosphorus showed a negative response to increased temperature.

It was concluded that further research relating element uptake and translocation to temperature is needed. Element accumulation in the roots, stems, leaves, and floral and seed portions of the plant should be included. In addition, the interaction between plant age and element concentration should be studied more thoroughly. Both this study and the published literature indicate that this interaction is significant for many of the elements.     

The influence of root hairs on the uptake of phosphate

Abstract

The uptake of phosphate from stirred solution by roots was not affected by root hairs. In contrast to this, root hairs appreciably increased the uptake of phosphate from a clay soil.     

Calcium (45CA2+) absorption by sorghum seedling root tips in the presence of ruthenium red and verapamil

Sorghum bicolor (L.) Moench. cv GP‐10, SC283, SC574, and Funk 6522DR seedling root tips (1 cm) absorption of calcium (⁴⁵Ca²⁺) in the presence of 0.1 mM ruthenium red (RR) and verapamil (0, 0.01, 0.1, 1.0, or 10 mM) was evaluated at pH 5.5. Verapamil was not inhibitory in Funk G522DR, significantly inhibited ⁴⁵Ca²⁺ absorption at 1.0 mM verapamil in GP‐10, SC283, and SC574 by 35, 65, and 55%, respectively. Genetic variation is documented. Additionally, as yet unrecognized physiological parameters seem to induce changes in response by the various cultivars.     

水稻根长增长和养分吸收动态及其模拟模型

采用溶液培养和田间试验研究水稻根长增长和氮磷钾吸收动态。在改进蔬菜根长和养分吸收动态模型基础上,建立了适用于一个生长周期的水稻根长增长模型、单位根表面积氮磷钾吸收速率模型及其累积吸收动态模型。6个根长增长模型和18个根表氮磷钾吸收速率模型以及36个氮磷钾吸收动态模型的模拟效果达统计显著水平。结果表明,随着种植时间的推移,水稻根长增长和氮磷钾累积吸收量在整个生育期呈现S型特征;根表养分吸收速率在生长前期随种植时间迅速提高并达到最大值,过后则按指数规律下降。溶液培养试验看出,生育期120 d水稻最大根长增长速率和最大根长分别为播种后（68.85.4）d和（108.43.9）d,品种间差异很小;最大根长增长速率和根长则为（4531.51529.4）cm/( pot?d)和 (2.8931 0.6237)105 cm/pot,品种间差异较大。田间试验看出,不同施肥处理的氮磷钾吸收速率基本同步,早晚稻插秧后约50~60 d根系养分吸收能力达到峰值,临近成熟时养分吸收量达到高峰。研究结果为水稻中后期养分管理提供了科学依据。