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| Articles
by
H.D. Laughinghouse |
Total Records (
3 ) for
H.D. Laughinghouse |
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R.C.L. Costa
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A.K.S. Lobato
,
C.F. Oliveira Neto
,
P.S.P. Maia
,
G.A.R. Alves
and
H.D. Laughinghouse
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The aim of this study was to evaluate and compare the
effects of water stress on biochemical and physiological parameters of
Vigna unguiculata (L.) Walp. (Sempre verde and Pitiuba), as well
as reveal the cultivar that better adapts under water stress. The experimental
design was randomized entirely in factorial, with 2 cultivars (Sempre
verde and Pitiuba), combined with 2 water conditions (stress and control).
Tenors of proline, free amino acids, total soluble carbohydrates and total
soluble proteins were quantified and the nitrate reductase activity was
measured. The plants submitted to stress suffered an increase in the amounts
of proline, since this solute is an osmotic adjuster. There was an increase
in the amounts of amino acids due to an increase in the protease enzyme
activity and an increase in the total carbohydrate levels, caused by the
increase of starch. A decrease in the amounts of total protein caused
by the decrease in their synthesis and a fall in nitrate reduction activity
caused by the low nitrate influx were reported. These responses were seen
in both cultivars. The Pitiuba cultivar presented responses that show
better osmotic adjustment in these conditions, revealing a greater adaptability
of this cultivar in conditions of hydric stress. |
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C.A.L. Hister
,
H.D. Laughinghouse
,
C.B. Da Silva
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T.S. Do Canto Dorow
and
S.B. Tedesco
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Aloysia gratissima is used in Brazilian folk medicine for the treatment of digestive and respiratory diseases. The infusions (6 and 24 g L-1) and essential oils (0.25%, on ethanol) were prepared and we used groups of five Allium cepa bulbs for each treatment. A total of 2500 cells per treatment were analyzed and the mitotic indexes were calculated. The antiproliferative effect of infusions and essential oils of Aloysia gratissima on the Allium cepa (onion) cell cycle was evaluated using the leaves of studied specimens. The infusions presented a significant decrease in the mitotic index (4.55% at 6 g L-1 and 2.04% at 24 g L-1) compared to the control-water (6.83%), as well as for the essential oil (2.58%), in comparison to the control-ethanol (3.65%). This investigation showed that the infusions and essential oil of Aloysia gratissima present important antiproliferative effects on the Allium cepa cell cycle. |
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A.K.S. Lobato
,
L.M. Luz
,
R.C.L. Costa
,
B.G. Santos Filho
,
A.C.S. Meirelles
,
C.F. Oliveira Neto
,
H.D. Laughinghouse
,
M.A.M. Neto
,
G.A.R. Alves
,
M.J.S. Lopes
and
H.K.B. Neves
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The aim of this study was to investigate responses promoted by external application of silicon on nitrogen components in Capsicum annuum L. plants submitted to water deficiency. The experimental design was completely randomized, with 4 treatments (0, 0.25, 1.00 and 1.75 μM Si). Leaf relative water content suffered significant changes, with values of 51.9, 66.1, 68.9 and 74.4% in 0, 0.25, 1.00 and 1.75 μM Si treatments, respectively. In total soluble proteins under concentrations of 0, 0.25, 1.00 and 1.75 μM Si were obtained values of 3.8, 4.8, 5.5 and 4.9 mg g DM-1, respectively. This study suggests that exogenous silicon alleviates negative effects promoted by water deficiency on leaf relative water content, stomatal conductance, total soluble proteins, total soluble amino acids and glycinebetaine. Furthermore, the nitrate reductase activity were observed significant benefits only at the concentration of 0.25 μM Si+, however in free ammonium was no obtained improvement after silicon application. Proline level was maximized at concentrations of 1.00 and 1.75 μM Si. |
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