AOBPreview originally published online on July 9, 2003
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Annals of Botany 92: 357-364, 2003
© 2003 Annals of Botany Company
Effect of Irradiance on the Partitioning of Assimilated Carbon During the Early Phase of Grain Filling in Rice
1 Department of Applied Plant Science, Graduate School of Agricultural Sciences, Tohoku University,Tsutsumidori-Amamiyamachi, Sendai 9818555, Japan
* For correspondence. Fax +81 22 717 8766, e-mail hikomae{at}biochem.tohoku.ac.jp
Received: 3 January 2003; Returned for revision: 31 March 2003; Accepted: 20 May 2003 Published electronically: 9 July 2003
 |
ABSTRACT |
|---|
 TOP ABSTRACT INTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONCONCLUSIONLITERATURE CITED |
|---|
Low irradiance in the early phase of grain filling in rice often results in a low grain yield, but its effects on the partitioning of previously or recently assimilated carbon within the plant or panicle have not been seriously examined. The objective of this study was to demonstrate the effect of shading during the different stages in the early phase of grain filling on the partitioning of previously or recently assimilated carbon among constituent organs and into superior and inferior spikelets of the panicle in rice (Oryza sativa L. ‘Sasanishiki’) plants using 13C as a tracer. Plants were grown either under low (shading) or moderate (non-shading) irradiance (120 and 800 µmol quantum m–2 s–1) for 3 or 4 d before or after the 13CO2 feeding at heading, full-heading or milky stages during the early phase of grain filling. Four days after the 13CO2 feeding, the proportion of labelled (previously assimilated) carbon partitioned into the panicle was 17 % higher in plants grown under low irradiance compared with plants grown under moderate irradiance at the full-heading stage (7–11 d after heading), while the proportion partitioned into the culm was 13 % lower. The light treatments for 3 d were conducted before the 13CO2 feeding and partitioning of the labelled (recently-assimilated) carbon into spikelets was examined 6 h after feeding. The amount of labelled carbon partitioned into the spikelets of the secondary branch (inferior grains) in the plants grown under low irradiance was only 31 % when compared with plants grown under moderate irradiance at the full-heading stage, although the partitioning of labelled carbon into the apical spikelets of the primary branch (superior grains) was not affected by the light treatments. These results clearly indicate that preferential partitioning of assimilated carbon into the panicle occurs under low irradiance at around 7–11 d after heading and that the priority of superior spikelets for assimilated carbon intensifies. This phenomenon is thought to be an important strategy for such rice cultivars as used in this study to achieve a certain proportion of ripened grains even under light limited conditions.
Key words: 13C, carbon partitioning, grain filling, low irradiance, rice, Oryza sativa L., sink strength.
|
INTRODUCTION |
|---|
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONCONCLUSIONLITERATURE CITED |
|---|
The yield of field-grown rice strongly depends on the solar irradiance throughout the growth period, especially during grain filling (Yoshida, 1981; Nishiyama, 1985). Low irradiance reduces the photosynthetic rate, resulting in a reduction in the amount of carbon available for grain development (Tanaka and Matsushima, 1971). During the early phase of grain filling in rice as in other gramineous plants, the assimilated carbon is temporarily stored as non-structural carbohydrates in the culm and leaf sheath (Evans and Wardlaw, 1976; Tsukaguchi et al., 1996). A highly positive correlation is obtained between the amount of stored non-structural carbohydrate available per grain in the initial 10 d of grain filling and the relative growth rate of grain in field-grown rice (Tsukaguchi et al., 1996). This period corresponds to the reported time in which endosperm cell number is determined. Previous reports have also shown that the amounts of carbohydrate in the culm and leaf sheath decrease rapidly in artificially shaded field-grown rice (Soga and Nozaki, 1957; Ota et al., 1958; Yoshida, 1981). Furthermore, the effect of shading on dry matter accumulation in the spikelets depends on the position of the spikelet within the panicle (Oshima, 1966; Kato, 1986). The above-cited research suggests that changes in the partitioning of assimilated carbon at the whole plant level and within the spikelets occur under low light conditions during the early phase of grain filling. However, the effects of low irradiance at different stages of the early phase of grain filling on the partitioning of stored or recently assimilated carbon within the plant or panicle has not been dealt with quantitatively.
In a previous paper (Okawa et al., 2002), we characterized the process of partitioning and remobilization of carbon assimilated at different stages during the early phase of grain filling in rice grown under controlled environmental conditions. The results indicated that a shift of the major sink from the culm to the panicle occurs at the beginning of the milky stage (around 10 d after heading; 10 DAH).
The objective of the present research was to demonstrate quantitatively the effect of shading (low irradiance) at heading, full-heading and milky stages in the early phase of grain filling on the partitioning of previously assimilated carbon among the constituent organs (Experiment 1) or recently assimilated carbon into the superior and inferior spikelets of the panicle (Experiment 2) in rice using 13C as a tracer, and to discuss the strategy of rice plants for grain filling under limited light conditions.
|
MATERIALS AND METHODS |
|---|
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONCONCLUSIONLITERATURE CITED |
|---|
Experiment 1 (effect of shading on partitioning of previously assimilated carbon among constituent organs)
Plant culture.
Rice (Oryza sativa L. ‘Sasanishiki’) was grown hydroponically in a temperature-controlled glasshouse (S-203A; Koito, Yokohama, Japan). The total area of the glasshouse was 4·12 m2 with an average height of 1·95 m. The glasshouse temperature was maintained at 25 °C during the day and 20 °C during the night. Light was supplemented with six 400 W metal halide lamps (MLR BOC400F-U; Mitsubishi Electric Osram Ltd, Yokomama, Japan) with a 14-h lighting regime (0600–2000 h) until the start of expt 1 and expt 2 (as described below).
Rice seeds were soaked in tap water for 36 h at 30 °C, and the seedlings were grown for 21 d on a plastic net floating on tap water with pH adjusted to 5·2. On day 21, eight seedlings each were transplanted into 44 pots containing 3·7 L of nutrient solution. The basal nutrient solution contained 1·0 mM NH4NO3, 0·6 mM NaH2PO4, 0·3 mM K2SO4, 0·3 mM CaCl2, 0·3 mM MgCl2, 45 µM Fe-EDTA, 50 µM H3BO3, 9 µM MnSO4, 0·3 µM CuCl2, 0·7 µM ZnSO4 and 0·1 µM Na2MoO4. The nutrient solution was renewed once a week and the pH was adjusted to 5·2 with 2 M HCl. The strength of the nutrient solution ranged from 1/4- to full-strength depending on the growth period (Mae and Ohira, 1981): 1/4-strength, 0–2 weeks after transplantation; 1/2-strength, 2–4 weeks after transplantation; 3/4-strength, 4–8 weeks after transplantation; full-strength, 8 weeks after transplantation to 1 week before heading; 1/4-strength [NH4NO3 replaced by (NH4)2SO4], 1 week before heading to 3 weeks after heading; tap water only, 3 weeks after heading to harvest. Heading time when panicles emerged from 40–50 % of the reproductive tillers was 98 d after seeding. At this stage, reproductive and non-reproductive tillers could be easily distinguished by their height. The height of non-reproductive tillers was half the average height of the reproductive tillers. The number of panicles per plant in the non-shading treatments was 3·5 ± 0.6 (n = 4). There was no difference in the number of panicles between the light treatments.
13CO2 feeding.
Plants were fed with 13CO2 at 0, 7 and 14 DAH, respectively. At the time of the second feeding, 90 % of the reproductive tillers had completed heading (full-heading stage). At the time of the third feeding, a higher rate of dry matter deposition had started in the panicle (milky stage). Eight pots were transferred to a growth chamber (LPH-0·3PS; NK System, Osaka, Japan (volume: 3·9 m3) 4 d before each 13CO2 feeding. The chamber was maintained under a 14-h (0600–2000 h) photoperiod, day/night temperatures of 25/20 °C, 60 % relative humidity, and a photosynthetic photon flux density of 800 µmol quanta m–2 s–1 at canopy height. Light was supplemented with two 250 W metal halide lamps (D250F; Toshiba Lighting & Technology Corporation, Tokyo, Japan) and 14 96 W fluorescent bulbs (12 x National FPR96EX-N/A bulbs and 2 x National FPR96EX-N/A bulbs; Matsushita Electric Industrial Co. Ltd, Osaka, Japan). The plants were fed 13CO2 for 3 h (1000–1300 h) at each feeding. 13CO2 gas was produced by the reaction of HCl and Ba13CO3. Hydrochloric acid was added at a constant rate (40 mmol h–1) to the Ba13CO3 (99 atom%, 10 g) suspension (200 ml) in the chamber. During feeding with 13CO2, air inflow was stopped by switching off the ventilator and sealing the duct. One day before the experiment, a trial run was carried out under the same conditions, except that BaCO3 was used instead of Ba13CO3 to check the changes in the partial pressure of CO2 in the chamber during the experimental period. The partial pressure of CO2 measured with an infrared CO2 analyser (G-MP111; Vaisala, Helsinki, Finland) in the chamber was 35–40 Pa during the first 2 h, and then gradually declined to 20–25 Pa at the end of the feeding (3 h after). At the end of the feeding period, air was introduced from outside by opening the duct and switching on the ventilator. Air in the chamber was fully replaced with atmospheric air within 14 min. The plants were then grown in the same chamber with shading or without shading as described below.
Light treatment.
After each 13CO2 feeding, shading treatment was performed for half of the pots with a 85 % shade cloth, while the other half remained without shading. The light treatments were continued for 4 d because our previous experiments had shown that the redistribution of assimilated 13C among constituent organs was mostly completed within 4 d (Okawa et al., 2002). The light intensity was 120 µmol quanta m–2 s–1 (corresponds to the solar irradiance during a cloudy day) for the shading treatment, and 800 µmol quanta m–2 s–1 (corresponds to the solar irradiance on a moderate sunny day) for the non-shading treatment at canopy height. This was done because the Pacific Ocean side of northern Japan sometimes experiences relatively cold and cloudy weather during summer.
Sampling and analysis.
On the last day of light treatments, eight plants from each light treatment were sampled for measurements of labelled carbon. Two plants each were used as a set for four replicates. The harvested plants were divided into panicles, leaf blades, leaf sheathes, culms, roots, and non-reproductive tillers and dead leaves. Samples were freeze-dried, weighed and ground to a fine powder in a vibrating mill (MC-4A; Itoh Seisakusyo Ltd, Tokyo, Japan). The amount of labelled carbon in the sample was calculated with the following equation: (the carbon content of each sample) x [(13C atom% of sample) – (13C atom% of natural abundance)]/100. The carbon content in the samples was determined with an elemental analyser (NA2500; Fisons Instruments, Milan, Italy). Measurement of 13C atom% in the samples was performed by a combustion method using an infrared 13CO2 analyser (EX-130S; Japan Spectroscopic Co. Ltd, Tokyo, Japan).
Experiment 2 (effect of shading on partitioning of recently assimilated carbon into superior and inferior spikelets)
Rice plants were cultured under the same conditions as in the Experiment 1. Heading time was 99 d after seeding. Eight pots were transferred to the growth chamber 1 d before each light treatment. The same light-treatment (shading and non-shading treatments) as in Experiment 1 was performed on days 0, 7 and 14 DAH and continued for 3 d. After each light treatment, plants were fed with 13CO2 as in Experiment 1. This experiment was conducted to determine the effect of shading on the early distribution of recently assimilated carbon into the superior and inferior spikelets at different positions on the panicle. The five apical spikelets of the top five primary branches (superior grains) and the five secondary spikelets of the bottom five secondary branches (inferior grains) of the panicle on the main stem were sampled 6 h after each 13CO2 feeding. Two plants each were used as a set for four replicates. The total number of spikelets per panicle of the main stem in the non-shaded treatments was 81 ± 4 (n = 4). The light treatments did not affect the number of spikelets per panicle.
Statistics
The experiments were a completely randomized design with four replicated levels. The significance of light treatments was assessed by ANOVAs. LSD and standard errors were used to determine the significance of differences between the treatments.
|
RESULTS |
|---|
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONCONCLUSIONLITERATURE CITED |
|---|
Experiment 1
Plant growth.
Figure 1 shows the changes in the dry mass of the whole plant and each plant part from just before heading to the full-ripening stage in rice grown under the non-shading condition.
|
Dry mass of the whole plant increased linearly in the early phase of the grain filling period (Fig. 1). The increase in panicle dry mass can be represented by a sigmoid curve with a rapid rise at around 10 DAH. The dry mass of the culm also increased linearly until 10 DAH. Thereafter, the culm mass declined until 30 DAH. In contrast to panicle and culm mass, the decreases in the dry mass of the leaf blade and leaf sheath had already begun before 10 DAH. The fraction of ‘non-reproductive tillers and dead leaves’ gradually increased after 20 DAH. However, the dry mass of root did not change significantly during the grain filling period.
Effect of shading on the dry mass.
Figure 2 shows the increase in dry mass of the whole plant and each plant part during the light treatments. At the whole plant level, there was a considerable increase in dry mass in the non-shaded treatment at all growth stages. In contrast, the increase was almost negligible in the shading treatment at all the stages (Fig. 2A). However, the panicle dry mass increased in both the non-shading and shading treatments (Fig. 2B). Increased culm dry mass was observed in the non-shading treatment at the heading and full-heading stages, while culm dry mass decreased in the shading treatment by the full-heading stage (Fig. 2C). At the milky stage, culm dry mass decreased in both light treatments. The increase in leaf sheath dry mass was observed at the heading stage and had become negligible at the full-heading stage in the non-shading treatment, whereas in the shading treatment it had become negative by the heading stage itself (Fig. 2E). Differences in leaf sheath dry mass between the treatments were negligible at the milky stage. There were no significant changes in dry mass of the leaf blade, ‘non-reproductive tillers and dead leaves’ and root fractions comparing the treatments except for the leaf blade at the full-heading stage (Fig. 2D, F and G).
|
Effect of shading on the partitioning of previously assimilated carbon (13C) into the organs.
Table 1 shows the amount of labelled carbon which remained in the whole plants after shading for 4 d at each stage. In the shading treatment, the amount of labelled carbon was slightly lower (5–12 %) at all the stages, although a significant difference between the light treatments was found only at the full heading stage.
|
Figure 3 shows changes in the proportion of labelled carbon among plant parts at 4 d after the 13CO2 feeding. In the panicle, the proportion of labelled carbon increased from 25–28 % at the heading stage to 70–72 % at the milky stage (Fig. 3A) in both light treatments. At the full-heading stage, the proportion of labelled carbon partitioned into the panicle was significantly larger in the shading treatment (68 %) than in the non-shading treatment (51 %), although there was no effect of the light treatments on the proportion of labelled carbon at the heading and milky stages. The proportion of labelled carbon in the culm was relatively high (48–51 %) in both treatments at the heading stage and there was no difference in the proportion between the treatments (Fig. 3B). The proportion in the culm decreased in both treatments at the full-heading stage, but the decrease was much larger in the shading treatment than in the non-shading treatment. The proportion of labelled carbon in the culm was 20 % in the shading treatment and 33 % in the non-shading treatment. No difference in the proportion was found between the treatments at the milky stage. In the leaf sheath, the proportion of labelled carbon content was 11 % in the shading treatment and 14 % in the non-shading treatment at heading stage (Fig. 3D). The proportion decreased to less than 5 % in both treatments at the full-heading stage. It was smaller in the shading treatment than in the non-shading treatment as in the culm. The proportion of labelled carbon in the leaf blade, ‘non-reproductive tillers and dead leaves’, and the root was relatively small and was less than 6 % in both treatments throughout the three stages, although some small differences were found between the treatments (Fig. 3C, E and F).
|
Experiment 2
Growth of superior and inferior grains.
Figure 4 shows the changes in the dry mass of superior and inferior grains between heading and full ripening in rice grown under non-shaded conditions. For both the superior and inferior grains, the changes of dry mass can be represented by sigmoid curves. During the first shading period, the dry mass of both types of grain did not increase. The dry mass began to rapidly increase only in superior grains during the second shading period, and the dry mass of both types of grain rapidly increased during the third shading period (Fig. 4).
|
Effect of shading on the dry mass.
Figure 5 shows the dry mass of the superior spikelet (A, C) and inferior spikelet (B, D) just after each shading treatment (A, B) and at the time of harvesting (C, D). There were no significant effects of shading treatment on individual spikelet weight, regardless of the spikelet positions and the time of measurements under the conditions employed here (Fig. 5).
|
Effect of pre-shading on the partitioning of recently assimilated carbon (13C) into the spikelets.
Figure 6 shows the content of labelled carbon in the superior spikelets (A) and the inferior spikelets (B) 6 h after 13CO2 feeding. The shading treatment did not have any significant effect on the labelled carbon content in the superior spikelets at all stages in the early phase of grain filling (Fig. 6A). In the inferior spikelets, however, the content of labelled carbon in the shading treatment was reduced considerably at the full-heading stage and it was only 31 % of that in the non-shading treatment at 10 DAH (Fig. 6B). The differences in the content of labelled carbon in both superior and inferior grains were not significant at 3 DAH and 17 DAH.
|
|
DISCUSSION |
|---|
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONCONCLUSIONLITERATURE CITED |
|---|
In this study, we attempted to quantify the effect of low irradiance on the partitioning of assimilated carbon during the early phase of grain filling in rice by using 13C as a tracer.
In Experiment 1, panicle growth was maintained and continued in both moderate and low irradiances, although no dry mass increase in the whole plant was observed under low irradiance at any of the stages (Fig. 2A and B). The growth of the panicle under low irradiance was supported by the enhanced remobilization of previously assimilated and accumulated carbon in the plant and by the preferential partitioning of recently assimilated carbon into the panicle. The enhancement of labelled carbon allocation into the panicle was compensated by a reduction of the proportion of labelled carbon partitioned into the other organs, especially in the culm and leaf sheath, in which the sum of decreases in the proportion (culm 13 % + leaf sheath 3 %) of labelled carbon was almost as great as the increased proportion (17 %) of labelled carbon in the panicle (Fig. 3). These results demonstrate that the preferential partitioning of dry matter into the panicle occurs under low irradiance in this rice cultivar. These are in agreement with previous field research on dry matter partitioning in plants with different rice cultivars (Soga and Nozaki, 1957; Ota et al., 1958). The proportions of labelled carbon partitioned into the leaf blade, ‘non-reproductive tillers and dead leaves’ and root fractions were much smaller compared with those in the culm and the leaf sheath (Fig. 3). The results indicate that the contribution of these organs to the grain filling, as reservoirs for carbohydrates, is limited and almost negligible. At around 10 DAH, as shown by the growth curve (Fig. 1), panicle growth was vigorously accelerated, presumably due to the rapid development of endosperm tissues and the substantial deposition of dry matter (Hoshikawa, 1967). The enzyme activities related to starch synthesis in the endosperm are enhanced at this stage (Nakamura and Yuki, 1992; Liang et al., 2001).
In expt 2, the distribution of recently assimilated (labelled) carbon into the inferior spikelets was clearly decreased in the plants grown under low irradiance at the full-heading stage and the superiority of the superior spikelets was greatly intensified (Fig. 6). These results suggest that there is a high sensitivity of photoassimilate partitioning among the spikelets to low irradiance in the plants at this stage. Iwasaki et al. (1992) reported that the dry mass of the inferior spikelets of the same cultivar increased immediately after thinning of the superior spikelets at around 10 DAH. Regulatory mechanisms of dry matter partitioning among spikelets are, however, not known. Actual dry mass of inferior spikelets just after the shading treatments and at harvest did not differ between the plants grown under the low and moderate irradiances in this experiment (Fig. 5). The growth conditions after the shading treatments seemed to be within a possible range for inferior spikelets to recover their proper development and grain filling.
|
CONCLUSION |
|---|
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONCONCLUSIONLITERATURE CITED |
|---|
It is suggested that under low irradiance at around 10 d after heading, the priority of the panicle and the superior spikelets of the panicle in the partitioning of previously and recently assimilated carbon is intensified by the compensational decrease of assimilates into the culm and the leaf sheath and into the inferior spikelets in the rice cultivar used in this experiment. This phenomenon is thought to be an important strategy, at least for the type of rice cultivars used in this experiment, to achieve a certain proportion of ripened grains, even under conditions of low irradiance.
|
ACKNOWLEDGEMENTS |
|---|
We wish to thank Dr S. Seneweera for critical reading of the manuscript. This work was supported by Grant-in-Aid for Scientific Research 12460028 from the Japanese Ministry of Education, Culture, Sports, Science and Technology and by Grant JSPS-RFTF 96L00604 for Research for the Future from the Japanese Society for the Promotion of Science.
|
LITERATURE CITED |
|---|
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONCONCLUSIONLITERATURE CITED |
|---|
-
Evans LT, Wardlaw IF. 1976. Aspects of the comparative physiology of grain yield in cereals. Advance in Agronomy 28: 301–359.
Hoshikawa K. 1967. Studies on the development of endosperm in rice. 1. Process of endosperm tissue formation. Proceeding of the Crop Science Society of Japan 36: 151–161 [in Japanese with English summary].
Iwasaki Y, Makino A, Mae T. 1992. Nitrogen accumulation in the inferior spikelet of rice ear during ripening. Soil Science and Plant Nutrition 38: 517–525.
Kato T. 1986. Effect of the shading and rachis-branch clipping on the grain-filling process of rice cultivars differing in the grain size. Japan Journal of Crop Science 55: 252–260.
Liang J, Zhang J, Cao X. 2001. Grain sink strength may be related to the poor grain filling of indica-japonica rice (Oryza sativa) hybrids. Physiologia Plantarum 122: 470–477.
Mae T, Ohira K. 1981. The remobilization of nitrogen related to leaf growth and senescence in rice plant (Oryza sativa L.). Plant and Cell Physiology 22: 1067–1074.
Nakamura Y, Yuki K. 1992. Changes in enzyme activities associated with carbohydrate metabolism during the development of rice endosperm. Plant Science 82: 15–20.[CrossRef]
Nishiyama I. 1985. Relation between rice yield and photosynthetically active solar radiation during seed ripening stage in selected prefectures in Japan. Japan Journal of Crop Science 54: 8–14 [in Japanese with English summary].
Okawa S, Makino A, Mae T. 2002. Shift of the major sink from the culm to the panicle at the early stage of grain filling in rice (Oryza sativa L. cv. Sasanishiki). Soil Science and Plant Nutrition 48: 237–242.
Oshima M. 1966. Translocation and redistribution of assimilated 14C in rice plant. Journal of Science of Soil Manure, Japan 37: 589–593.
Ota Y, Yamada N, Kami S, Tajima K, Funayama K. 1958. Studies on ripening of rice. 2. Effect of shading treatment on the ripening. Proceeding of the Crop Science Society of Japan 27: 196–200 [in Japanese with English summary].
Schnyder H. 1993. The role of carbohydrate storage and redistribution in the source–sink relations of wheat and barley during grain filling. New Phytologist 123: 233–245.[CrossRef]
Soga Y, Nozaki M. 1957. Studies on the relation between seasonal changes of carbohydrates accumulated and the ripening at the stage of generative growth in rice. Proceeding of the Crop Science Society of Japan 26: 105–108 [in Japanese with English summary].
Tanaka T, Matsushima S. 1971. Analysis of yield-determining process and its application to yield-prediction and culture improvement of lowland rice. CIV. Effects of light intensity and different shading methods during the ripening period on the percentage of ripened grains. Proceeding of the Crop Science Society of Japan 40: 376–380 [in Japanese with English summary].
Tsukaguchi T, Horie T, Ohnishi, M. 1996. Filling percentage of rice spikelets as affected by availability of non-structural carbohydrates at the initial phase of grain filling. Japan Journal of Crop Science 65: 445–452 [in Japanese with English summary].
Wardlaw IF. 1990. The control of carbon partitioning in plants. New Phytologist 116: 341–381.[CrossRef]
Yoshida S. 1981. Fundamentals of rice crop science. Los Baños, Manila: The International Rice Research Institute, 84–94, 231–233.
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  T. Ishimaru, T. Hirose, T. Matsuda, A. Goto, K. Takahashi, H. Sasaki, T. Terao, R.-i. Ishii, R. Ohsugi, and T. Yamagishi Expression Patterns of Genes Encoding Carbohydrate-metabolizing Enzymes and their Relationship to Grain Filling in Rice (Oryza sativa L.): Comparison of Caryopses Located at Different Positions in a Panicle Plant Cell Physiol., April 1, 2005; 46(4): 620 - 628. [Abstract] [Full Text] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||