P132-01 Photosynthetic induction in Eucalyptus urograndis
seedlings and cuttings measured by an open photoacoustic cell
Barja PR, Mansanares AM, da Silva EC, Magalhães ACN, Alves
PLCA
The differences in PA signals of seedlings and cuttings of four-month-old
Eucalyptus are associated with differences between the photosystem
2 antenna systems of these samples.
Photosynthetica 39: 489-495, 2001. IF = 0.807
P133-01 Photosynthesis in Eucalyptus studied by
the open photoacoustic technique: effects of irradiance and temperature
Barja PR, Mansanares AM, da Silva EC, Magalhães ACN, Alves
PLCA
The usefulness of the Open Photoacoustic Cell technique to study the
effects of irradiance and temperature on photosynthesis was demonstrated
in this paper.
Acoustical Physics 47: 16-21, 2001. IF = 0.363
P134-01 Purification and properties of asparaginase
from the testa of immature seeds of pea (Pisum sativum L.)
Chagas EP, Sodek L*
A potassium dependent asparaginase was purified 1328 fold from testas
of immature pea seeds and characterized. Antibodies were raised against
the purified protein.
Brazilian Archives of Biology and Technology 44: 239-246, 2001. IF
= 0.050
*E-mail: lsodek@unicamp.br
P135-01 N-partitioning, nitrate reductase and glutamine
synthetase activities in two contrasting varieties of maize
Machado AT, Sodek L*, Fernandes MS
Translocation efficiency of N and photoassimilates to the developing
grain and the source-sink relationship were significantly different
for the two varieties of maize studied. NR and GS activities did not
differ between varieties. N content of the plant or grain was a useful
parameter for characterizing efficient use of N.
Pesquisa Agropecuaria Brasileira 36: 249-256, 2001. IF = 0.010
*E-mail: lsodek@unicamp.br
P136-01 Nitrate reductase and glutamine synthetase
activities in S1 endogamic families of the maize populations Sol da
Manhã NF and Catetão
Machado AT, Sodek L*, Paterniani E, Fernandes MS
NR and GS activities were measured in two contrasting varieties of
maize in terms of N efficiency use. The data are discussed in relation
to the response of these enzymes under different N regimes.
Revista Brasileira de Fisiologia Vegetal 13: 88-102, 2001
*E-mail: lsodek@unicamp.br
P137-01 Efeitos do nível de inóculo
de Meloidogyne incognita no algodoeiro
Abrão MM, Mazzafera P*
Neste estudo acompanhou-se a variação de alguns parâmetros
fisiológicos em algodão, em resposta a inoculação
com baixas doses de inóculo de Meloidogyne incognita raça
3. Duas cultivares foram utilizadas, Acala e IAC-20, respectivamente,
suscetível e moderadamente resistente. Plântulas com
duas folhas foram inoculadas com 500 ou 5.000 ovos, e 90 dias depois
foram comparadas com plantas não inoculadas, quanto à
massa da parte aérea e raízes, fotossíntese,
atividade da enzima redutase do nitrato, e teores de clorofila e açúcares
solúveis. Aos 90 dias algumas plantas também foram submetidas
à deficiência hídrica e o potencial da água
determinado nas folhas. O maior nível de inóculo levou
à redução da parte aérea (massa de folhas)
em Acala. Com 500 ovos ocorreu estímulo em ambas cultivares,
uma vez que houve tendência de maior crescimento da parte aérea.
Em Acala houve maior crescimento de raiz com o aumento do inóculo,
provavelmente devido à emissão de raízes secundárias
nos pontos de penetração do nematóide e também
pela formação de galhas. Houve aumento dos teores de
clorofila e açúcares solúveis, e da fotossíntese
com o aumento do inóculo. Discute-se isto em relação
à maior demanda de fotoassimilados para suportar o crescimento
de raízes em Acala. Na IAC-20 isto estaria ligado aos mecanismos
de defesa induzidos pelo ataque do nematóide. Após o
estresse hídrico o potencial da água diminuiu na IAC-20
e aumentou na Acala, com o aumento do inóculo. O aumento do
potencial da água nesta última cultivar poderia estar
ligado ao crescimento das raízes, principalmente a emissão
de novas raízes secundárias, enquanto que a resposta
na IAC-20 seria a resposta normal, ou seja, de deficiência hídrica.
Bragantia 60: 19-26, 2001
*E-mail: pmazza@obelix.unicamp.br
P138-01 Seed storage proteins in coffee
Baú SMT, Mazzafera P*, Santoro LG
It has been reported that Coffea arabica seeds contain as the main
reserve protein, a legumin-like protein, constituted of two subunits,
a and b, of approximately 35 and 20 kDa. In this work the seed proteins
of several coffee species and varieties were investigated by SDS-PAGE
and gel filtration. No differences were observed in the electrophoretic
profiles among varieties of C. arabica, however, marked differences
were observed among species, or even among individuals of some species.
In general, the molecular weight of the subunits a and b accounted
for a monomer of 48 to 62 kDa. However, native molecular weight obtained
by gel filtration showed that there is association of 6 of such proteins,
in a hexamer. The most marked difference was observed for C. canephora
and C. racemosa. The former clearly showing isoforms of the subunits,
and the later showing absence of the b subunit. The influence of proteases
in this observations is discussed.
Revista Brasileira de Fisiologia Vegetal 13: 31-40, 2001
*E-mail: pmazza@obelix.unicamp.br
P139-01 Effect of a drought period on the mobilisation
of non-structural carbohydrates, photosynthetic efficiency and water
status in an epiphytic orchid.
Stancatto GC, Mazzafera P*, Buckeridge MS
Environmental stress induces modifications and adaptations, a marked
characteristics of epiphytic orchids. The presence of the pseudobulb
is associated with carbohydrate reserve functions and water maintenance
in the plant. We evaluated the effects of drought on carbohydrate
metabolism in plants subjected to drought fot 0,25 and 45 d by masuring
the following parameters: Fv/Fm ratio, ethanol and water-soluble polysaccharides,
acid invertase activity, relative water content, concentration of
osmotically active solutes and dry mass/fresh mass ratio. Our results
showed that a period of drought decreased the efficiency of the photochemical
system at the same time the ratio of sucrose/monosaccharides was constant
in the leaf, but increased in the pseudobulb. As a consequence of
the changes in sucrose/monosaccharides ratio in the pseudobulb, plants
under drought stress have decreased invertase activity and increased
concentration of osmotically active solutes. The pseudobulb stores
a glucomannan, thought to be a multifunctional carbohydrate involved
in water stress and carbon reserve.
Plant Physiology and Biochemistry 39: 1009-1016, 2001. IF = 1.333
*E-mail: pmazza@obelix.unicamp.br
