Perubahan Fisiologi, Fotosintesis, dan Struktur

ABSTRAK
SRI BANON. Perubahan Fisiologi Fotosintesis dan Struktur Anatomi Daun Tanaman C3 dan C4
Akibat Cekaman Kekeringan. Dibimbing oleh HAMIM dan DORLY.
Penelitian ini bertujuan untuk mengetahui perubahan fisiologi, fotosintesis, dan struktur
anatomi daun tanaman C3 dan C4 akibat cekaman kekeringan. Tanaman padi (C3), Echinochloa
(E. crusgalli) dan alang-alang (Imperata cylindrica) (C4), ditumbuhkan dalam polybag dan
disiram secara teratur hingga mencapai umur enam minggu, kemudian diberi perlakuan cekaman
kekeringan selama enam hari dan disiram kembali untuk dilihat respon penyembuhannya. Selama
cekaman kekeringan, tanaman diamati karakter fisiologi, fotosintesis, dan struktur anatomi daun.
Pengamatan struktur anatomi daun dilakukan menggunakan mikroskop cahaya dan mikroskop
transmisi elektron (TEM). Perlakuan cekaman kekeringan selama enam hari, nyata menurunkan
status air media dan daun ketiga tanaman, tinggi tanaman, dan jumlah daun tanaman alang-alang
dan padi, tetapi tidak menurunkan tinggi tanaman, jumlah daun, dan anakan tanaman Echinochloa.
Cekaman kekeringan nyata menurunkan kadar air relatif daun tanaman dan nilai parameter
fotosintesis yang didasarkan pada nilai qP pada tanaman Echinochloa dan padi, namun tidak pada
alang-alang. Walaupun demikian cekaman kekeringan selama enam hari menyebabkan penurunan
nilai Fv/Fm ketiga tanaman. Cekaman kekeringan tidak memberikan pengaruh yang nyata
terhadap struktur umum anatomi daun ketiga tanaman, tetapi berdasarkan pengamatan dengan
TEM cekaman kekeringan meningkatkan secara nyata jumlah kloroplas sel seludang pembuluh
tanaman Echnochloa, dan meningkatkan secara tajam jumlah pati pada sel mesofil tanaman padi
serta sel mesofil dan sel seludang pembuluh tanaman Echinochloa.
Kata kunci: kekeringan, anatomi daun, dan fotosintesis
ABSTRACT
SRI BANON. Changes of Physiology, Photosynthesis, and Leaf Anatomy Structure of C3 and C4
Plants in Response to Drought Stress. Supervised by HAMIM and DORLY.
Present research aimed to find out changes of physiology, photosynthesis, and leaf
anatomy of C3 and C4 plants in response to drought stress. Rice (C3 plant), Echinochloa (E.
crusgalli) and alang-alang (Imperata cylindrica) (C4 plants) were grown in polybag and regularly
watered untill six weeks, then they were treated by drought for six days. The plants were watered
again after drought to find out the capacity of recovery. During drought stress, the plants were
analysed their physiological characters, photosynthesis, and leaf anatomy structure. Leaf anatomy
structure was observed using light microscope and transmission electron microscope (TEM). The
six days drought significantly decreased water status of the media and plant leaves, plant height,
and number of leaves of alang-alang and rice, but it did not decrease plant height, number of
leaves, and tillers of Echinochloa. The drought stress significantly decrease relative water contain
and photosynthesis parameter value based on the decreased qP value of Echinochloa and rice, but
not in alang-alang. Meanwhile, drought stress caused slightly reduction of Fv/Fm of all the plants.
The drought stress did not affect significant anatomical structure of the leaves of the three plants.
However based on the observation of TEM the drought stress significantly increased the number
of chloroplast in bundle sheet cell of Echinochloa and increased the starch in mesofil cell of rice
and in mesofil cell as well as bundle sheet cell of Echinochloa.
Keyword: drought, leaf anatomy, and photosynthesis