Genetics of Leaf Water Potential and its Relationship with Drought Avoidance Components in Rice (Oryza sativa L.)

2003 ◽  
Vol 3 (9) ◽  
pp. 760-765 ◽  
Author(s):  
M.K. Bashar . ◽  
Khaleda Akter . ◽  
K.M. Iftekharuddaula . ◽  
M.S. Ali .
2006 ◽  
Vol 97 (2-3) ◽  
pp. 142-154 ◽  
Author(s):  
V. Sibounheuang ◽  
J. Basnayake ◽  
S. Fukai

2014 ◽  
Vol 4 (2) ◽  
Author(s):  
Song Ai Nio ◽  
Audry Agatha Lenak

Abstrak Penggulungan daun merupakan salah satu bentuk resistensi terhadap kekeringan atau lebih tepatnya mekanisme menghindari kekeringan pada tumbuhan monokotil. Mekanisme ini terjadi dengan cara menurunkan laju evapotranspirasi atau dengan meningkatkan absorpsi air pada tanah kering untuk mempertahankan potensial air daun tetap tinggi. Proses penggulungan daun ini berkaitan erat dengan peranan sel kipas. Pada saat kekurangan air, jumlah dan ukuran sel kipas meningkat, sehingga daun akan menggulung. Tingkat penggulungan daun dapat ditentukan secara visual berdasarkan sistem standar evaluasi untuk tanaman padi dengan memberi skor 1-9. Rendahnya tingkat penggulungan daun berkorelasi positif dengan meningkatnya potensial air daun. Kata kunci: menghindari kekeringan, penggulungan daun Abstract Leaf rolling is one mechanism of drought resistance, i.e. drought avoidance. This mechanism was resulted from decreasing evapotranspiration rate or increasing water absorption in the dry soil to maintain high leaf water potential. The process of leaf rolling in monocotyledon was closely related to the activity of bulliform cells. The number and size of bulliform cells were increased under water deficit, so that leaf rolling occurred. Leaf rolling score (1-9) could be visually determined based on the system of standard evaluation in rice. The low leaf rolling score was positively correlated with high leaf water potential. Keywords: drought avoidance, leaf rolling


Forests ◽  
2019 ◽  
Vol 10 (12) ◽  
pp. 1119
Author(s):  
Thuy T. Nguyen ◽  
Stefan K. Arndt ◽  
Patrick J. Baker

Deciduous dipterocarp forest (DDF) is the most extensive forest type in continental Southeast Asia, but across much of its range is functionally more similar to tropical savannas than tropical forests. We investigated water relations and drought responses of the four dominant tree species (two Shorea and two Dipterocarpus species) of the DDF in central Vietnam to determine how they responded to prolonged periods of drought stress. We quantified leaf water relations in nursery- and field-grown seedlings of the four species and conducted a dry-down experiment on 258 seedlings to study leaf water potential and morphological responses of the seedlings following the drought stress. The two Shorea and two Dipterocarpus species differed significantly in leaf water potential at turgor loss point and osmotic potential at full turgor, but they showed similar responses to drought stress. All species shed leaves and suffered from stem loss when exposed to water potentials lower than their turgor loss point (approximately −1.7 MPa for Dipterocarpus and −2.6 MPa for Shorea species). Upon rewatering, all species resprouted vigorously regardless of the degree of leaf or stem loss, resulting in only 2% whole-plant mortality rate. Our results suggest that none of the four deciduous dipterocarp species is drought tolerant in terms of their water relations; instead, they employ drought-adaptive strategies such as leaf shedding and vigorous resprouting. Given that all species showed similar drought avoidance and drought-adaptive strategies, it is unlikely that seasonal drought directly influences the patterns of species assembly in the DDF of Southeast Asia.


Weed Science ◽  
1983 ◽  
Vol 31 (3) ◽  
pp. 410-414 ◽  
Author(s):  
Rolando T. Cruz ◽  
John C. O'Toole ◽  
Keith Moody

Twenty days after rice (Oryza sativaL. ‘IR28’) emergence, water was withheld from the stress treatment for 20 days while the control was kept well-watered by furrow irrigation. In the control plots, rice leaf water potential at 0800 hours was –5.5 bars and leaf length 30 cm on the 12th day of stress. In the stress treatment, leaf water potential decreased to –8 bars and leaf length to 20 cm, when no weeds competed with rice. With maximum weed competition, rice leaf water potential decreased to –18 bars and leaf length to 15.5 cm. on the 20th day of stress, dawn (0600 h) leaf water potential of rice in the stress treatment was reduced from –8 bars when no weeds competed with rice to –19 bars when competition was maximum. The weed species had higher water potential values than the rice in both control and water-stress treatments.


2018 ◽  
Vol 18 (2) ◽  
pp. 63
Author(s):  
Risa Junita Mereh ◽  
Nio Song Ai ◽  
Parluhutan Siahaan

KANDUNGAN AIR PADA SEGMEN DAUN TANAMAN PADI (Oryza sativa L.) LOKAL SULAWESI UTARA SAAT KEKERINGAN YANG DIINDUKSI DENGAN POLIETILEN GLIKOL 8000 ABSTRAKPenelitian ini telah dilakukan untuk mengkaji kandungan air sebagai respon fisiologi pada segmen daun tanaman padi lokal Sulut (varietas Temo, Ombong, Burungan, dan Superwin) terhadap kekeringan yang diinduksi dengan PEG 8000 secara in vitro. Segmen daun padi dipotong-potong 1 cm x 1 cm dan diberi tiga macam perlakuan PEG 8000 (dengan potensial air/PA medium 0; -0,25; dan -0,5 MPa), dan empat waktu pengambilan sampel (0, 4, 8 dan 12 jam) dalam tiga kali ulangan. Hasil penelitian menunjukkan bahwa bahwa faktor varietas, faktor waktu perlakuan,  faktor konsentrasi PEG 8000, dan interaksi antara ketiga faktor tersebut tidak menyebabkan perbedaan kandungan air segmen daun yang nyata.Kata kunci: Cekaman kekeringan, PEG 8000, Potensial air, Segmen daun LEAF WATER CONTENT IN LEAF SEGMENTS OF NORTH SULAWESI LOCAL RICE (Oryza sativa L.)  UNDER POLYETHYLENE-GLYCOL- 8000-INDUCED DROUGHTED DROUGHTABSTRACTA study was conducted to evaluate leaf water content as one of physiological responses in leaf segments of North Sulawesi local rice (cv. Temo, Ombong, Burungan, and Superwin) under PEG 8000- induced-drought. The rice leaves were cut into 1 cm x 1 cm segments and treated withPEG 8000 solutions  (medium water potential or PA of 0; -0.25; and -0.5 MPa),four sampling times (0, 4, 8 and 12 hours) and 3 replicates. The results indicated that factors of varieties, treatment period, concentration of PEG 8000, and interaction among these factors did not result in any differences in water content of rice leaf segments.Keywords: Drought stress, PEG 8000, Water potential, Leaf segment


1983 ◽  
Vol 100 (2) ◽  
pp. 429-439 ◽  
Author(s):  
A. J. Karamanos ◽  
J. B. Drossopoulos ◽  
C. A. Niavis

SUMMARYThe course of free proline accumulation in leaves, stems, roots and ears was examined during the development of the wheat cultivars Yecora and Generoso grown in the field with or without irrigation. More negative values of leaf water potential were associated with higher amounts of free proline in the various organs. In most cases, proline accumulated more readily with increasing water stress before heading than after ear emergence in the leaves, stems and roots of both varieties. Differences between the two cultivars concerning the sensitivity of the mechanisms inducing proline accumulation to water stress existed mainly in the reproductive phase: Generoso accumulated proline more readily than Yecora. There is evidence that the increased amounts of free proline in Generoso can be associated with more effective dehydration and drought avoidance mechanisms.


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