Abstract
Aims To investigate the changes in physiological
parameters in leaves of field-grown rice genotypes
differing in their salt tolerance.
Methods Thirty rice cultivars classified as tolerant
(T; 11), moderately tolerant (MT; 5), moderately sensitive
(MS; 7) and sensitive (S; 7) based on the previous
screening at the seedling stage were established in a
greenhouse. Thirty-day-old seedlings were then transplanted
to a rice field, situated in a moderately saline
area in northeastern Thailand, where EC slowly increased
from 2.03 to 6.46 dS m−1 from the transplanting
date to harvest. Leaf samples (the third leaves from the
top or the flag leaves during the vegetative or the reproductive
phase, respectively) were collected, at 1 month
intervals, when the plants were 60-, 90-, 120- and 150-
day-old corresponding to active tillering, early reproductive,
late reproductive and harvest stage, respectively.
Leaf samples were analyzed for changes in proline,
chlorophyll and malondialdehyde (MDA). The harvested
panicles were evaluated for the percentage of
filled grain weight and the concentration of Na+ and
K+ in the top internode.
Results The patterns of change and the mean concentrations
of most physiological parameters in rice
leaves during the course of development were strikingly
similar for the four classes of salt tolerance.
Proline concentration remained relatively constant
throughout the development and finally showed a
dramatic increase in the flag leaves at harvest. MDA
concentration tended to increase with age reaching the
maximum in the flag leaves at harvest. The chlorophyll
concentration was higher during the vegetative
stage than the reproductive stages. At harvest
corresponding to the time of maximum salinity, the T
group tended to contain higher proline and stayed
green longer than the other groups. Moreover, the T
group showed higher percentage filled grain weight
which was associated with lower Na+/K+ ratio in the
top internode. The percentage filled grain weight was
negatively correlated with Na+ concentration and
Na+/K+ ratio in the top internode and proline concentration
in flag leaves, but did not correlate with chlorophyll
and MDA in flag leaves
AbstractAims To investigate the changes in physiologicalparameters in leaves of field-grown rice genotypesdiffering in their salt tolerance.Methods Thirty rice cultivars classified as tolerant(T; 11), moderately tolerant (MT; 5), moderately sensitive(MS; 7) and sensitive (S; 7) based on the previousscreening at the seedling stage were established in agreenhouse. Thirty-day-old seedlings were then transplantedto a rice field, situated in a moderately salinearea in northeastern Thailand, where EC slowly increasedfrom 2.03 to 6.46 dS m−1 from the transplantingdate to harvest. Leaf samples (the third leaves from thetop or the flag leaves during the vegetative or the reproductivephase, respectively) were collected, at 1 monthintervals, when the plants were 60-, 90-, 120- and 150-day-old corresponding to active tillering, early reproductive,late reproductive and harvest stage, respectively.Leaf samples were analyzed for changes in proline,chlorophyll and malondialdehyde (MDA). The harvestedpanicles were evaluated for the percentage offilled grain weight and the concentration of Na+ andK+ in the top internode.Results The patterns of change and the mean concentrationsof most physiological parameters in riceleaves during the course of development were strikinglysimilar for the four classes of salt tolerance.Proline concentration remained relatively constantthroughout the development and finally showed aเพิ่มที่กระบอกในค่าสถานะใบที่เก็บเกี่ยว MDAความเข้มข้นที่มีแนวโน้มจะ เพิ่มขึ้นตามอายุถึงสูงสุดในธงใบที่เก็บเกี่ยว คลอโรฟิลคือความเข้มข้นสูงในช่วงที่พืชขั้นกว่าขั้นตอนการสืบพันธุ์ ที่เก็บเกี่ยวที่สอดคล้องกับเวลาของความเค็มสูงสุด Tกลุ่มที่มีแนวโน้มมีสูงขึ้นเป็น และพักสีเขียวยาวมากกว่ากลุ่มอื่น ๆ นอกจากนี้ Tกลุ่มที่พบสูงขึ้นเปอร์เซ็นต์เต็มเม็ดน้ำหนักซึ่งเป็นสิ่งที่เกี่ยวข้องกับนาล่าง ++ K + อัตราส่วนในการinternode ด้านบน น้ำหนักเมล็ดเปอร์เซ็นต์เต็มไปได้มีความสัมพันธ์ในเชิงลบกับความเข้มข้น Na + และNa + K + อัตรา internode และ proline ความเข้มข้นสูงสุดในใบธง แต่ไม่ไม่ correlate กับคลอโรฟิลและ MDA ในใบธง
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