The accumulation of accessory pigments as a function of chlorophyll a. A comparison of development and genetic control

A comparison is made between pigment accumulation in pigment-deficient genotypes of soybean ( Glycine max ) at any one sampling time (genotype control) and pigment accumulation for any one genotype as a function of development (development control). Plots of accessory chloroplast pigments against chlorophyl a show various linear and non-linear relationships that are similar whether generated by genetic differences or by the development process. These relationships are related to the formation and development of pigment-protein complexes especially the relationship of carotenoids to these complexes.     

Infra-species Variation in Reactions to Hosts in Heterodera glycines Population

Eighteen hosts were inoculated with each of four races of Heterodera glycines. A discriminant function analysis of the reactions of these races to these hosts demonstrated that these races could be separated but not consistently. Then 33 H. glycines populations collected from 13 states and five obtained from Japan were tested on differential hosts. The number of variants discriminated within these 38 populations depended on the number of differentials and the rating system used. When five differentials were used with a (+) or (-) rating system there were six "races," but when 13 differentials were used with a (+) or (-) system there were 25 physiological groups. If an index rating system was used there were 36 groups. Apparently H. glycines is a very variable species and delineation of races varies with criteria chosen.     

Serine protease inhibitors inhibit superoxide production by human basophils stimulated by anti-IgE

Anti-IgE-induced O₂^? production by human basophils was inhibited by potent inactivators of serine proteases. The inhibitory effect of the inhibitor and substrate for chymotrypsin-type protease was much greater than that of those substances for trypsin-type protease. These findings suggest that chymotrypsin-like serine proteases are involved in basophil O₂^? production.     

Effect of polyamines on ethylene production

The polyamines putrescine, cadaverine, spermidine and spermine reduced the amount of ethylene produced by senescing petals of Tradescantia but they did not prevent anthocyanin leakage from these same petals. These polyamines also inhibited auxin-mediated ethylene production by etiolated soybean hypocotyls to less than 7 % of the control. The basic amino acids lysine and histidine reduced the amount of auxin-induced ethylene produced by soybean hypocotyls by ca 50 %. In the hypocotyls, methionine was unable to overcome the inhibition caused by the polyamines. The polyamines spermidine and spermine inhibited ethylene production induced by the application of 1-aminocyclopropane-1-carboxylic acid and they also reduced the endogenous content of this amino acid in the treated tissues.     

Embryonic control of isocitrate lyase activity in cotyledons of germinating soybean

The activity of isocitrate lyase (EC 4.1.3.1) in the cotyledons of germinating soybean is controlled by the embryonic axis. Plant growth regulators like gibberellic acid, indole acetic acid and 2,4-dichlorophenoxy acetic acid are able to increase the enzyme activity in cotyledons of whole seedlings but not in dissected cotyledons. The control of induction of the enzyme activity during germination by the embryo could be mediated by the elaboration of kinetin.     

Photosynthesis in flashing light in soybean leaves grown in different conditions. I. Photosynthetic induction state and regulation of ribulose-1,5-bisphosphate carboxylase activity

The photosynthetic induction state under conditions of different lightfleck frequencies or durations, or different shade periods was studied in soybean leaves in order to examine how it might limit utilization of sunflecks in leaf canopies. Induction following an increase in photon flux density (PFD) from strongly limiting to saturating PFDs exhibited two phases; a fast-inducing one, requiring about 1 min and a slow one, requiring up to 60 min for completion. Transfer of fully induced leaves to low light resulted in a rapid decrease in the fast-inducing component, a slower decrease in the slow-inducing component and an even slower decrease in stomatal conductance. Therefore, the decreases in extent of induction appeared to be due to biochemical factors and not to stomatal closure. Under flashing light regimes consisting of 1-s lightflecks given at different frequencies for long periods, a constant induction state was achieved, the measure of induction state increased with the frequency of the lightflecks. This constant induction state also depended on the growth conditions, with shade leaves having a higher value than those grown at high light at any particular lightfleck frequency. The measure of induction state was mostly lower in flashing light as compared to constant light of the same mean PFD, particularly in leaves with a low light saturation point and in short lightflecks. Initial activities of ribulose-1,5-bisphosphate carboxylase (rubisco) were also higher in continuous light and were highly correlated with the measure of induction state. The rapid decrease in extent of induction of soybean leaves during shade periods is an important limitation to the ability of the leaves to respond to light increases similar to those occurring with sunflecks. At least part of the limitation on carbon assimilation during sunflecks due to photosynthetic induction is based on regulation of rubisco activity.     

Purification and some properties of γ-conglycinin in soybean seeds

A 7S globulin (γ-conglycinin) which was one of four major antigenic components in soybean globulins was purified and found to be homogeneous on ultracentrifugation, disc electrophoresis, immunoelectrophoresis and disc electrofocusing by gel filtration, preparative-scale disc electrophoresis and two kinds of affinity chromatography. Subsequently, some physico-chemical properties of the protein were determined. The sedimentation coefficient, isoelectric point, MW and diffusion constant were 6·55S, pH 5·80, 104000 and 5·80 × 10^?7 cm²/sec, respectively. The protein was a glycoprotein which contained 5·49% total carbohydrate per protein. The protein did not aggregate and dissociate with a change of ionic strength from 0·1 to 0·5.     

Soybean alcohol dehydrogenase

Alcohol dehydrogenase was prepared from germinating soybean seeds. Specific activity was increased from 511 to 31316 units. The coenzyme is NAD with a K_m of 10^?4M. Allyl alcohol is oxidized faster than ethanol; with the latter substrate, the K_m is 1.3 × 10^?2M, and the pH optimum 8.7. The enzyme catalyses acetaldehyde reduction, with a K_m of 10^?2M and a pH opt of 7.1. The MW is 53(±5) × 10^?3.