AUXIN-LIKE EFFECT OF HUMIC SUBSTANCES EXTRACTED FROM FECES OF ALLOLOBOPHORA-CALIGINOSA AND ANTENNARIA-ROSEA

Leaf explants of Nicotianaplumbaginifolia were compared in cultures supplemented with IAA, inhibitors of IAA (TIBA = 2,3,Qriiodobenzoic acid and PCIB = 4-chlorophenoxy-isobutyric acid) and a humic substance (HEf) obtained from the faeces of Allolobophora caliginosa and A. rosea. The results show that HEf at a concentration of 1 mg Cl- \u2019 causes root development from leaf explants that appears to be similar to MA-induced activity, while the control did not develop roots. Furthermore HEf induced longer roots than those grown in IAA with fewer hair roots. In the presence of the IAA inhibitors, the leaf explants were without roots. Humic matter, IAA and IAA-inhibitors stimulated peroxidase activity in N. plumbaginifolia. Also, when the Nicotiana tissues were treated with the humic fraction and IAA there was a minor polymorphism in the esterase isoenzymes. The presence of both TIBA and PCIB restored the esterase profile obtained from control tissues. The induced root-forming activity in leaf explants and the minor polymorphism with respect to the control in the esterase zymograms demonstrate that the humic substance exhibited auxin-like activity. HEf, a low molecular size fraction, was obtained from the faeces of Ailolobophora caliginosa (Sav.) and A. rosea (Sav.) by disaggregating the humic material with acetic acid, confirmed the effectiveness of the combination of high acidity and low molecular size in influencing the biological activity of the plant system tested

Effect of humic substances on nitrogen uptake and assimilation in two species of pinus

The aim of this paper was to test the effect of forestry humic substances on nitogen uptake and on the activity of key enzymes of nitrogen assimilation in two differen species of pinus

Effect of molecular complexity and acidity of earthworm faeces humic fractions on glutamate dehydrogenase, glutamine synthetase, and phosphoenolpyruvate carboxylase in Daucus carota alpha II cells

Carrot cells were grown in cultures supplemented with two hormones [2,4-dichlorophenoxyacetic acid (2,4-D) and 6-benzylaminopurine (6BAP)] and two humic fractions extracted from earthworm faeces, one with high acidity and a low apparent molecular size (<3500) and the other with low acidity and a large molecular size. 2,4-D stimulated growth through an effect on eel enlargement, while the strongly acidic humic fraction (0.2 mg l(-1)) and the weakly acidic fraction (1 mg l(-1)) were both less effective. With 4-16 h of pre-incubation, the highly acid humic fraction, mainly alone, induced the best increase in protein content; the effect of the weakly acid humic fraction and the hormones was generally less important. The two humic fractions also differed in their influence on glutamate dehydrogenase activity. After 2 h of pretreatment, the highly acidic fraction increased glutamate dehydrogenase activity, while the other fraction did not affect it. After 4-16 h of pre-incubation, the activity of this enzyme was still not influenced by these humic fractions. The presence of the two hormones did not interfere with the humic matter effects. Glutamine synthetase activity was not affected by a pre-incubation of up to 4 h with the two humic fractions, but it was stimulated after 8-16 h of pre-incubation. A 2,4-D+6BAP mixture stimulated glutamine synthetase activity (from +12 to +50%). Again, the presence of the hormones did not interfere with the effects induced by the humic fractions. After 16 h of pre-incubation, phosphoenolpyruvate carboxylase activity was increased by the highly acidic humic fraction (+93%) and by both humic fractions together (+34%). An explanation of the different incubation times necessary for the humic fractions to exert stimulatory effects on these enzymes is proposed here. The regulatory properties of the strongly acidic humic fraction appeared to depend on the combination of high acidity (expecially carboxylic C) with low molecular size

The ascorbate system during the early stage of germination in Pinus laricio seeds treated with extracts from two different sources of humus

The aims of the paper was to study how the AA biosynthetic capacity, as well as the activities of REDOX enzymes of the ascorbate systems during the early stage of pinus laricio germination, were affected by humus from two forestry sites