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).     

Erythrosine B influence on sorghum root curvature and wheat leaf rust germling use of extracellular lipids

Root curvature response to unilaterally applied calcium (Ca²⁺) in agar was inhibited 81% by erythrosine B (EB) (10 nM) in sorghum [Sorghum bicolor (L.) Moench.] cv Funk G522DR, 70% in cv SC283, and 11% in cv SC574. EB (10 nM) is reported to totally inhibit Ca²⁺‐ATPase, while 10–50 μM EB is required to inhibit H⁺‐ATPase. Therefore, differences in relative concentrations of Ca²⁺‐ATPase and H+‐ATPase exist in the root plasma membranes (PM) of the three cultivars. Carbon dioxide (¹⁴CO₂) production from glycerol‐tri‐(1‐¹⁴C)‐palmitate by wheat (Triticum aestivum L.) leaf rust (Puccinia recondita Rob. ex Desm.) urediospore germlings was inhibited 85% by EB (10 nM).     

Coupling of dry matter and nutrient accumulation in forage grass

Abstract

The logistic model has proven very useful in relating dry matter production of forage grasses to applied nitrogen. A recent extension of the model coupled dry matter and plant ? accumulation through a common response coefficient c. The objective of this analysis was to establish the validity of the extended model for each of the three major nutrients (?, ?, ?), with a common coefficient c between dry matter and each applied nutrient. Analysis of variance established the validity of this hypothesis. The model accurately described response of dry matter, plant nutrient removal, and plant nutrient concentration to applied nutrient, with overall correlation coefficients of 0.9928, 0.9972, and 0.9975 for applied N, P, and K, respectively. Furthermore, the model closely described the relationship between yield and plant nutrient removal, as well as between plant nutrient concentration and plant nutrient removal, for each nutrient. This work confirmed earlier results for applied ? with various grasses and established the validity of the model for applied ? and ? for the first time. The logistic equation is well‐behaved and simple to use on a pocket calculator. It can be used to describe yields and nutrient removal in evaluation of agricultural production and environmental quality.     

Yield and mineral concentration of HiMag compared to other tall fescue cultivars grown in the southern piedmont

HiMag is an experimental cultivar derived from Missouri 96 (Mo96) and Kentucky 31 (K31) tall fescue (Festuca arundinacea Schreb.) parentage for increased calcium (Ca), magnesium (Mg), and reduced potassium (K)/ (Ca+Mg). Our objective was to determine productivity and mineral characteristics of endophyte‐free (E‐) HiMag in relation to standard tall fescue cultivars when grown in the Southern Piedmont Land Resource Area. In experiment 1, HiMag (E‐) and K31 (E‐) were grown at two levels of phosphorus (P), K, and lime additions to both severely eroded, and non‐eroded Cecil soil (clayey, kaolinitic, thermic family of Typic Hapludults). Herbage Ca and Mg were greater and K/(Ca+ Mg) and yield were less for HiMag than for K31. Phosphorus and K concentrations were not different. Herbage yields, P, Ca, and Mg concentrations were increased by P, K, and lime additions. In experiment 2, HiMag(E‐), K31(E‐), endophyte‐infected K31(E+), Mo I(E+), Mo II (E+), and AU Triumph (E‐) were planted either in a prepared seedbed or planted without tillage into the Cecil soil. HiMag yields were not different from Mo‐I, Mo‐II or K31(E±), but were less than those of AU Triumph (E‐). HiMag yield response to no‐till planting, past soil erosion, and fertilizer level was similar to that of K31 (E±). Fertilizer level, and soil condition affected the magnitude of differences in mineral levels in HiMag and K31 (E±), but K/(Ca+Mg) values were more favorable in HiMag. All tall fescue cultivars established equally well in no‐till or prepared seedbeds. Aside from a slightly lower first harvest yield there were no important effects of planting no‐till versus planting in a prepared seedbed. HiMag's agronomic attributes, while not superior to other cultivars, were sufficient to justify further testing to improve Mg nutrition of grazing animals.     

Inhibition of conversion of geranylgeranyl-chlorophyll to phytol-chlorophyll by S-ethyl dipropylthiocarbamate (EPTC)

The influence of EPTC (S-ethyl dipropylthiocarbamate) on the hydrogenation of geranylgeranylchlorophyll (GG-Chl) to phytol-Chl was studied during the greening (6-, 12-, 18-, 24-, and 48-hr incandescent light exposure) of etiolated wheat [Triticum aestivum (L.) cv “Stacy”] and sorghum [Sorghum bicolor (L.) Moench cv “G 522DR”] seedlings grown in nutrient solution containing ¹⁴C-labeled sodium acetate. Chloroplast pigment synthesis occurred and small quantities of GG-Chl were found in both Chl^?a and Chl^?b. When wheat seedlings were greened for 48 hr in an EPTC concentration series (1 nM to 100 μM), geranylgeraniol (GG) content increased from 11% (control) to 60% (100 μM EPTC) of the isoprenoid alcohol esterified to chlorophyllide a, but Chl-b contained ≤1% GG-Chl at all concentrations of EPTC. Sorghum seedlings greened for 48 hr in the same EPTC concentration series contained about 3% GG (control) while 100 and 40% GG esterified to chlorophyllide a and chlorophyllide b, respectively, after 48 hr exposure to 100 μM EPTC. Thus, EPTC prevented hydrogenation of GG-Chl to phytol-Chl on the Chl molecule more in sorghum than in wheat.