Fotosintesis Sebagai Proses Dasar.
FOTOSINT ESIS SEBAGAI PROSES DASAR
MAKALAH
Intan Ratna Dewi A.
132 306 081
Budidaya Pertanian/ Agronomi
FAKULTAS PERTANIAN
UNIVERSITAS PADJADJARAN
BANDUNG
2007
Diurnal variat ion of photosynthesis and photoinhibit ion in
tea: effects of irradiance and nitrogen supply during growt h
in the field
A. J. Mohot t i 1, 2 and D. W. Lawl or 1, 3
1
Biochemist ry
and
Physiol ogy
Harpenden, Hert s AL5 2JQ, UK
epart
D
ment ,
IACR-Rot hamst ed,
Journal of Experiment al Bot any, Vol . 53, No. 367, pp. 313-322, February
1, 2002© 2002 Oxf ord Uni versit y Press
I. ABSTRACT
Diurnal changes i n t he rat e of phot osynt hesis (A) of mat ure t ea
( Camel l ia si nensis (L. ) O. Kunt ze) bushes grown at high el evat ion in t he
f iel d i n Sri Lanka, were rel at ed t o envi ronment al condit ions. Bushes were
eit her unshaded, receivi ng 100% of incident phot osynt het ical l y act ive
radiat ion (PAR), moderat el y shaded, (65% PAR) or heavil y shaded (30%
PAR).
These
t reat ment s
were combined
wit h
nit rogen
f ert ilzer
i
appl icat ions of 0, 360 and 720 kg ha-1 year-1. When recent l y f ul l y
expanded l eaves were measured under t he growing condit ions on bright ,
cl ear days f rom dawn t o dusk, A was great est in t he morning wit h
increasing radi at ion bet ween approximat ely 8 h and 10 h. St omat al
conduct ances ( gs) and subst omat al carbon dioxid e concent rat ions (Ci )
were t hen l arge, l eaf t emperat ures ( TL) cool , and sat urat ed wat er vapour
def icit s (VPD) smal l . However, as t he irradi ance, TL and VPD increased
1
t owards midday, A, gs, phot ochemical quenching, and Ci decreased, and
non-phot ochemical
quenching
increased.
In
t he
l at e
af t ernoon,
irradi ance, TL and VPD f el l , but despit e t he rel at ivel y l arge increase in gs
and Ci , A remained l ow; however, it recovered overnight . The zero-N
t reat ment decreased t ot al -N cont ent of l eaves by 50% and A by c. 20%
(not
signif icant ). Leaves of unshaded pl ant s receiving l east
N had
signi f icant l y ( P
MAKALAH
Intan Ratna Dewi A.
132 306 081
Budidaya Pertanian/ Agronomi
FAKULTAS PERTANIAN
UNIVERSITAS PADJADJARAN
BANDUNG
2007
Diurnal variat ion of photosynthesis and photoinhibit ion in
tea: effects of irradiance and nitrogen supply during growt h
in the field
A. J. Mohot t i 1, 2 and D. W. Lawl or 1, 3
1
Biochemist ry
and
Physiol ogy
Harpenden, Hert s AL5 2JQ, UK
epart
D
ment ,
IACR-Rot hamst ed,
Journal of Experiment al Bot any, Vol . 53, No. 367, pp. 313-322, February
1, 2002© 2002 Oxf ord Uni versit y Press
I. ABSTRACT
Diurnal changes i n t he rat e of phot osynt hesis (A) of mat ure t ea
( Camel l ia si nensis (L. ) O. Kunt ze) bushes grown at high el evat ion in t he
f iel d i n Sri Lanka, were rel at ed t o envi ronment al condit ions. Bushes were
eit her unshaded, receivi ng 100% of incident phot osynt het ical l y act ive
radiat ion (PAR), moderat el y shaded, (65% PAR) or heavil y shaded (30%
PAR).
These
t reat ment s
were combined
wit h
nit rogen
f ert ilzer
i
appl icat ions of 0, 360 and 720 kg ha-1 year-1. When recent l y f ul l y
expanded l eaves were measured under t he growing condit ions on bright ,
cl ear days f rom dawn t o dusk, A was great est in t he morning wit h
increasing radi at ion bet ween approximat ely 8 h and 10 h. St omat al
conduct ances ( gs) and subst omat al carbon dioxid e concent rat ions (Ci )
were t hen l arge, l eaf t emperat ures ( TL) cool , and sat urat ed wat er vapour
def icit s (VPD) smal l . However, as t he irradi ance, TL and VPD increased
1
t owards midday, A, gs, phot ochemical quenching, and Ci decreased, and
non-phot ochemical
quenching
increased.
In
t he
l at e
af t ernoon,
irradi ance, TL and VPD f el l , but despit e t he rel at ivel y l arge increase in gs
and Ci , A remained l ow; however, it recovered overnight . The zero-N
t reat ment decreased t ot al -N cont ent of l eaves by 50% and A by c. 20%
(not
signif icant ). Leaves of unshaded pl ant s receiving l east
N had
signi f icant l y ( P