Cytokinin concentration gradient in the developing grains and upper leaves of rice (Oryza sativa) during grain filling

1986 ◽  
Vol 64 (9) ◽  
pp. 2068-2072 ◽  
Author(s):  
Shyamali Saha ◽  
P. K. Nagar ◽  
P. K. Sircar
Keyword(s):  
Oryza Sativa ◽  
Concentration Gradient ◽  
Developmental Stages ◽  
Oryza Sativa L ◽  
Flag Leaf ◽  
Grain Filling ◽  
Cytokinin Activity ◽  
Rice Grains ◽  
Nearest Neighbours ◽  
Developing Grains

Changes in cytokinin activity in the flag, first, second, and third leaves and in the developing grain of rice (Oryza sativa L.) were studied using the soybean callus bioassay in relation to the movement of photosynthate during different developmental stages. Cytokininlike activity in leaves was highest at the 85th day after transplantation. The flag leaf maintained higher cytokinin activity than other upper leaves. In grains high cytokininlike activity during the 1st week after anthesis is correlated with the grain setting and cell division period. The concentration gradient of cytokininlike substances in the upper parts of the plant was highest in the panicle after anthesis. The data suggest that the developing rice grains attract most of their photoassimilate from their nearest neighbours, the metabolically active flag, first, and second leaves.

Partitioning of 13C-labelled photosynthate varies with growth stage andpanicle size in high-yielding rice

2004 ◽  
Vol 31 (2) ◽  
pp. 131 ◽  
Author(s):  
Pravat K. Mohapatra ◽  
Yasuyuki Masamoto ◽  
Satoshi Morita ◽  
Junichi Takanashi ◽  
Tsuneo Kato ◽  
...  
Keyword(s):  
Oryza Sativa L ◽  
Flag Leaf ◽  
Source Area ◽  
Grain Filling ◽  
Rice Cultivar ◽  
Japonica Rice ◽  
Heavy Carbon ◽  
Heavy Carbon Isotope ◽  
Source Sink ◽  
Developing Grains

A super-high-yielding rice (Oryza sativa L.) cultivar, Takanari, and a traditional japonica rice cultivar, Nakateshinsenbon, were grown under field conditions to compare partitioning of 13C-labelled photosynthate to different plant organs during the period of reproductive development. The flag leaf and the two leaves immediately below it on the main culm were exposed individually to 13CO2 and the movement of the heavy carbon isotope to grains, hull, panicle branches and vegetative parts of plant was assessed. Also, the effect of a reduction of sink size on the partitioning of 13C to different organs was studied by removing some of the primary branches of the panicle. 13C taken up by the three leaves in the post-heading period, moved mostly to the grains and hull of the panicle. At this stage, the uppermost three leaves and the panicle consisted of a single source–sink unit. Partitioning of 13C to the rest of the vegetative structures of the plant was minimal. In the case of Nakateshinsenbon, the flag leaf supplied most of the carbon assimilates for the grains and contributions from the other two leaves were much smaller. However, in Takanari, the contribution of 13C to grains from the second leaf was equivalent to that of the flag leaf. In Takanari, removal of more than one third of the primary branches of the panicle significantly reduced partitioning from the third leaf of the culm, but partitioning from the flag leaf was not significantly changed. In contrast, branch removal treatment significantly depressed transport of carbon assimilates from the flag leaf in Nakateshinsenbon. The obligatory nature of the source–sink relationship in rice is discussed. It is concluded that in lower-yielding traditional rice, photosynthesis in the flag leaf supplies carbon assimilates to the developing grains. But in the super-yielding rice Takanari, the main source area is extended to include the two leaves below the flag leaf so as to sustain an extra large panicle. Even greater grain-filling is possible in super-yielding rice, if the source area is increased further.

Population-specific quantitative trait loci mapping for functional stay-green trait in rice (Oryza sativa L.)

Genome ◽  
2011 ◽  
Vol 54 (3) ◽  
pp. 235-243 ◽  
Author(s):  
Jin-Dong Fu ◽  
Yong-Feng Yan ◽  
Moon Young Kim ◽  
Suk-Ha Lee ◽  
Byun-Woo Lee
Keyword(s):  
Oryza Sativa ◽  
Quantitative Trait ◽  
Oryza Sativa L ◽  
Flag Leaf ◽  
Grain Filling ◽  
Parental Line ◽  
Stay Green ◽  
Spad Value ◽  
Trait Locus ◽  
Grain Filling Period

The functional stay-green trait gives leaves a longer duration of greenness and photosynthetic capacity during the grain-filling period. We developed two independent recombinant inbred line populations from the intra- and intersubspecific crosses of Oryza sativa L. subsp. japonica ‘Suweon490’ (japonica) × O. sativa subsp. japonica ‘SNU-SG1’ (japonica) and O. sativa subsp. indica ‘Andabyeo’ (indica) × O. sativa subsp. japonica ‘SNU-SG1’ (japonica), respectively. The common parental line ‘SNU-SG1’ was the functional source for the stay-green trait. Quantitative trait locus (QTL) mapping based on simple sequence repeat markers identified a total of six QTLs associated with two stay-green traits across two populations. The two traits were cumulative chlorophyll content (SPAD value) of flag leaf (CSFL) and total cumulative SPAD value of the four upper leaves (TCS). Four QTLs, tcs4, csfl6, csfl9 (or tcs9), and csfl12, located on chromosomes 4, 6, 9, and 12, respectively, were detected simultaneously in both populations. The remaining two QTLs, csfl2 (or tcs2) and tcs5, on chromosomes 2 and 5, respectively, were found to be population specific. Moreover, the functional stay-green trait of ‘SNU-SG1’ positively correlated with grain yield performance. Two yield QTLs, yld6 and yld9, on chromosomes 6 and 9 found in both populations were positioned at the same locations with the csfl6 and tcs9 QTLs for stay-green traits. Thus, the identified chromosomal regions can be promising targets of marker-assisted introgression of the functional stay-green trait into breeding materials for improvement of rice yield.

scholarly journals Quantitative Trait Loci Affecting Flag Leaf Development in Rice (Oryza sativa L.)

2003 ◽  
Vol 53 (3) ◽  
pp. 255-262 ◽  
Author(s):  
Sohei Kobayashi ◽  
Yoshimichi Fukuta ◽  
Satoshi Morita ◽  
Tadashi Sato ◽  
Mitsuru Osaki ◽  
...  
Keyword(s):  
Oryza Sativa ◽  
Quantitative Trait Loci ◽  
Quantitative Trait ◽  
Leaf Development ◽  
Oryza Sativa L ◽  
Flag Leaf ◽  
Trait Loci

Changes in Cytokinin Activity during Seed Germination in Rice (Oryza sativa L.)

1984 ◽  
Vol 54 (1) ◽  
pp. 1-5 ◽  
Author(s):  
SHYAMALI SAHA ◽  
P. K. NAGAR ◽  
P. K. SIRCAR
Keyword(s):  
Oryza Sativa ◽  
Seed Germination ◽  
Oryza Sativa L ◽  
Cytokinin Activity

scholarly journals Mechanical and Processing Properties of Rice Grains

2020 ◽  
Vol 12 (2) ◽  
pp. 552 ◽  
Author(s):  
Weronika Kruszelnicka ◽  
Andrzej Marczuk ◽  
Robert Kasner ◽  
Patrycja Bałdowska-Witos ◽  
Katarzyna Piotrowska ◽  
...  
Keyword(s):  
Grain Size ◽  
Oryza Sativa ◽  
Negative Correlation ◽  
Oryza Sativa L ◽  
Strength Properties ◽  
Rice Grain ◽  
Static Compression ◽  
Positive Correlation ◽  
Rice Grains ◽  
Processing Properties

Strength properties of grains have a significant impact on the energy demand of grinding mills. This paper presents the results of tests of strength and energy needed the for destruction of rice grains. The research aim was to experimentally determine mechanical and processing properties of the rice grains. The research problem was formulated in the form of questions: (1) what force and energy are needed to induce a rupture of rice grain of the Oryza sativa L. of long-grain variety? (2) what is the relationship between grain size and strength parameters and the energy of grinding rice grain of the species Oryza sativa L. long-grain variety? In order to find the answer to the problems posed, a static compression test of rice grains was done. The results indicate that the average forces needed to crush rice grain are 174.99 kg m·s−2, and the average energy is 28.03 mJ. There was no statistically significant relationship between the grain volume calculated based on the volumetric mass density Vρ and the crushing energy, nor between the volume Vρ and other strength properties of rice grains. In the case of Vs, a low negative correlation between strength σmin and a low positive correlation between the power inducing the first crack were found for the grain size related volume. A low negative correlation between the grain thickness a3, stresses σmin and work WFmax was found as well as a low positive correlation between thickness a3 and the force inducing the first crack Fmin.

scholarly journals Proteomic analysis of salicylic acid regulation of grain filling of two near-isogenic rice (Oryza sativa L.) varieties under soil drying condition

2020 ◽  
Vol 151 ◽  
pp. 659-672 ◽  
Author(s):  
Romesh Eric Romy Kimbembe ◽  
Guangyan Li ◽  
Guanfu Fu ◽  
Baohua Feng ◽  
Weimeng Fu ◽  
...  
Keyword(s):  
Salicylic Acid ◽  
Oryza Sativa ◽  
Proteomic Analysis ◽  
Oryza Sativa L ◽  
Grain Filling ◽  
Soil Drying ◽  
Drying Condition
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