Morphological development of rice caryopses located at the different positions in a panicle from early to middle stage of grain filling

2003 ◽  
Vol 30 (11) ◽  
pp. 1139 ◽  
Author(s):  
Tsutomu Ishimaru ◽  
Toshiaki Matsuda ◽  
Ryu Ohsugi ◽  
Tohru Yamagishi
Keyword(s):  
Cell Division ◽  
Grain Filling ◽  
Cell Number ◽  
Morphological Development ◽  
Endosperm Cell ◽  
Coordinated Development ◽  
Storage Tissue ◽  
Middle Stage

Rice caryopses show different patterns of grain filling depending on position within a panicle. Caryopses located on the upper primary rachis branches generally accumulate larger amounts of starch at maturity than caryopses located on the secondary rachis branches of the lower primary rachis. In this study, the former and latter types of caryopses were defined as superior and inferior caryopses, respectively. Superior caryopses elongated soon after flowering, whereas inferior caryopses hardly elongated and were morphologically stagnant until the first 4 d after flowering (DAF). However, once inferior caryopses began elongation, their morphological development was the same as superior caryopses until the middle stage of grain filling. Cell division of the inner integument ceased before endosperm cellularization, pericarp functioned as a transient starch storage tissue until endosperm accumulated starch, and endosperm cell number was determined concomitantly with nucellus disintegration. These results implied the coordinated development of the endosperm with maternal tissues. In addition, differences of inner-integument cell number and endosperm cell number were related to a difference of endosperm size between superior and inferior caryopses.

Application of abscisic acid regulates antioxidant enzymes activities and modulates endosperm cell division in winter wheat

2016 ◽  
Vol 96 (2) ◽  
pp. 283-295 ◽  
Author(s):  
Dongqing Yang ◽  
Dian Peng ◽  
Wei Yang ◽  
Yanping Yin ◽  
Yong Li ◽  
...  
Keyword(s):  
Antioxidant Enzymes ◽  
Abscisic Acid ◽  
Cell Division ◽  
Grain Filling ◽  
Grain Weight ◽  
Endosperm Cell ◽  
Filling Rate ◽  
Flag Leaves ◽  
Grain Filling Rate ◽  
Antioxidant Enzymes Activities

Effects of exogenous abscisic acid (ABA) on antioxidant enzymes activities and endosperm cell division of two wheat (Triticum aestivum L.) cultivars were investigated. Results showed that the superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) activity in flag leaves of both cultivars is elevated by application of ABA and it is correlated with less membrane damage: lower malondialdehyde (MDA). Exogenous ABA significantly increased endosperm cell number and endosperm division rate, finally increased grain weight. Although ABA treatment decreased endogenous zeatin riboside (ZR) content in flag leaves from 7 to 28 days after anthesis (DAA), indole acetic acid (IAA) levels were significantly increased by spraying with ABA. Correlation analysis showed that endogenous contents of ZR, ABA, and IAA in grains were positively and significantly correlated with grain-filling rate. IAA content in leaves was positively and significantly correlated with grain-filling rate. The results suggested that increased grain weight of ABA-treated plants was due to higher antioxidant abilities of flag leaf resulting in longer maintenance of photosynthetic capacity and higher grain-filling rate.

Factors Controlling Endosperm Cell Number and Grain Dry Weight in Wheat: Effects of Shading on Intact Plants and of Variation in Nutritional Supply to Detached, Cultured Ears

1984 ◽  
Vol 11 (3) ◽  
pp. 151 ◽  
Author(s):  
BK Singh ◽  
CF Jenner
Keyword(s):  
Cell Division ◽  
External Medium ◽  
Amino Nitrogen ◽  
Dry Weight ◽  
Cell Number ◽  
Soluble Carbohydrates ◽  
Endosperm Cell ◽  
Intact Plants ◽  
Organic Nutrients ◽  
Photon Exposure

The association between endosperm cell number and grain dry weight, and the dependence of endosperm cell division on the availability of organic nutrients, have been investigated in wheat. Two different procedures were used to vary the supply of nutrients to the grains during the phase of cell division. Detached ears were cultured in solutions of sucrose (0-60 g 1-1) and glutamine (0.125-0.75 g N 1-1), or intact plants were exposed to high (560 �mol m-2 s-1) or low (55 �mol m-2 s-1) photon irradiance. Cell number per endosperm, and grain dry weight, were both responsive to the concentration of nutrients in the external medium, and to the level of photon exposure. Average dry weight per cell was relatively independent of the level of nutrition or of photon exposure until cell division had ceased but, in the later stages of grain-filling, dry weight per cell in the cultured ears displayed a dependence upon the concentration of nutrients in the external medium. Amounts of sucrose, other soluble carbohydrates and soluble amino nitrogen were extracted from the grains and, on a per grain basis, the amounts of all fractions varied in response to variation in the level of nutrients supplied to the ears, and to photon exposure. However, concentrations of these nutrients in the developing grains, calculated on a dry weight or water basis, were not associated with the rate of cell division in the grains. While the evidence gathered supports the notion that growth (in cell number, and dry weight) of the developing endosperm is controlled inter alia by the provision of organic nutrients, the nature of the controlling mechanism is obscure. It seems that cellular division is not affected directly by nutritional supply through a mechanism involving the concentration of substrates for energy and protein synthesis within the developing grain.

scholarly journals Intra-plant variation for progress of cell division in developing oat grains: a preliminary study

2008 ◽  
Vol 13 (1-2) ◽  
pp. 163 ◽  
Author(s):  
A. RAJALA ◽  
P. PELTONEN-SAINIO
Keyword(s):  
Cell Division ◽  
Grain Filling ◽  
Cell Number ◽  
Sink Strength ◽  
Limited Growth ◽  
Plant Variation ◽  
Hormonal Balance ◽  
Oat Cultivars ◽  
Preliminary Study ◽  
Developing Grains

Development of an oat panicle proceeds from the uppermost terminal spikelet downward to the base of the panicle. The intra-panicle variation in development is likely to influence potential grain size. This may result from differences in activity and duration of the cell division phase, vascular transport capacity, duration of filling period and/or hormonal balance. In this preliminary survey we studied intra-panicle variation in pollination (when clusters of pollen were visibly attached to stigmatic branches) of florets and cell division in developing grains immediately after pollination of the oat cultivars Belinda and Fiia. We found substantial intra-panicle variation for both traits. The highest cell number was found in the uppermost, most advanced, primary grain, while secondary grains tended to have fewer cells compared with their counterpart primary grains irrespective of their position. Results of an additional experiment indicated that death of the primary floret in the conventional oat cultivar Virma prior to pollination, resulted in higher weight of secondary grain, though this never equalled that of the primary counterpart. This limited growth capacity may partly result from lower cell number. These results encourage us to continue with experiments on the contribution of groat cell number to sink strength and grain-filling capacity.;

Rapid endosperm development promotes early maturity in weedy rice (Oryza sativa f. spontanea)

Weed Science ◽  
2020 ◽  
Vol 68 (2) ◽  
pp. 168-178
Author(s):  
Can Zhao ◽  
Wenrong Xu ◽  
Lingchao Meng ◽  
Sheng Qiang ◽  
Weimin Dai ◽  
...  
Keyword(s):  
Oryza Sativa ◽  
Cell Division ◽  
Grain Filling ◽  
Endosperm Development ◽  
Starch Accumulation ◽  
Weedy Rice ◽  
Endosperm Cell ◽  
Cultivated Rice ◽  
Early Maturity ◽  
Grain Filling Period

AbstractEarly maturity allows weedy rice (Oryza sativa L. f. spontanea) to persist by escaping harvest in paddy fields. A shorter grain-filling period contributes to the early maturity of weedy rice. However, the differences in morphology and endosperm development in the caryopsis between weedy and cultivated rice are largely unexplored. Here, we selected four biotypes of weedy rice and associated cultivated rice (ACR; Oryza sativa) from different latitudes to conduct a common garden experiment. The endosperm development process of the caryopsis was observed by optical microscopy and electron microscopy. Endosperm cell division and starch accumulation rate during grain filling were also measured. The grain development progress in weedy rice was more rapid and earlier than that in ACR. The endosperm development progress of weedy rice was 6 to 8 d earlier than that of ACR. The endosperm cells of weedy rice cellularized earlier and more rapidly than those of ACR, and the starch grains of weedy rice were more sharply polygonal and compactly arranged than those of ACR. The active endosperm cell division period in weedy rice was 4 to 7 d shorter than that in ACR, while the active starch accumulation period of weedy rice was 2 to 8 d shorter than that of ACR. The rapid development of endosperm cells and starch grains leads to the shorter grain-filling period of weedy rice. weedy rice.

scholarly journals Sound Waves Promote Arabidopsis thaliana Root Growth by Regulating Root Phytohormone Content

2021 ◽  
Vol 22 (11) ◽  
pp. 5739
Author(s):  
Joo Yeol Kim ◽  
Hyo-Jun Lee ◽  
Jin A Kim ◽  
Mi-Jeong Jeong
Keyword(s):  
Arabidopsis Thaliana ◽  
Cell Division ◽  
Root Growth ◽  
Apical Meristem ◽  
Cell Number ◽  
Root Apical Meristem ◽  
Control Group ◽  
Auxin Signaling ◽  
Ethylene Signaling ◽  
Sound Waves

Sound waves affect plants at the biochemical, physical, and genetic levels. However, the mechanisms by which plants respond to sound waves are largely unknown. Therefore, the aim of this study was to examine the effect of sound waves on Arabidopsis thaliana growth. The results of the study showed that Arabidopsis seeds exposed to sound waves (100 and 100 + 9k Hz) for 15 h per day for 3 day had significantly longer root growth than that in the control group. The root length and cell number in the root apical meristem were significantly affected by sound waves. Furthermore, genes involved in cell division were upregulated in seedlings exposed to sound waves. Root development was affected by the concentration and activity of some phytohormones, including cytokinin and auxin. Analysis of the expression levels of genes regulating cytokinin and auxin biosynthesis and signaling showed that cytokinin and ethylene signaling genes were downregulated, while auxin signaling and biosynthesis genes were upregulated in Arabidopsis exposed to sound waves. Additionally, the cytokinin and auxin concentrations of the roots of Arabidopsis plants increased and decreased, respectively, after exposure to sound waves. Our findings suggest that sound waves are potential agricultural tools for improving crop growth performance.

The preimplantation pig embryo: cell number and allocation to trophectoderm and inner cell mass of the blastocyst in vivo and in vitro

Development ◽  
1988 ◽  
Vol 102 (4) ◽  
pp. 793-803 ◽  
Author(s):  
V.E. Papaioannou ◽  
K.M. Ebert
Keyword(s):  
Inner Cell Mass ◽  
Cell Mass ◽  
Staining Technique ◽  
Cell Number ◽  
Total Cell ◽  
Differential Staining ◽  
Morphological Development ◽  
Total Cell Number

Total cell number as well as differential cell numbers representing the inner cell mass (ICM) and trophectoderm were determined by a differential staining technique for preimplantation pig embryos recovered between 5 and 8 days after the onset of oestrus. Total cell number increased rapidly over this time span and significant effects were found between embryos of the same chronological age from different females. Inner cells could be detected in some but not all embryos of 12–16 cells. The proportion of inner cells was low in morulae but increased during differentiation of ICM and trophectoderm in early blastocysts. The proportion of ICM cells then decreased as blastocysts expanded and hatched. Some embryos were cultured in vitro and others were transferred to the oviducts of immature mice as a surrogate in vivo environment and assessed for morphology and cell number after several days. Although total cell number did not reach in vivo levels, morphological development and cell number increase was sustained better in the immature mice than in vitro. The proportion of ICM cells in blastocysts formed in vitro was in the normal range.

scholarly journals The Rho-family GTPase OsRac1 controls rice grain size and yield by regulating cell division

2019 ◽  
Vol 116 (32) ◽  
pp. 16121-16126 ◽  
Author(s):  
Ying Zhang ◽  
Yan Xiong ◽  
Renyi Liu ◽  
Hong-Wei Xue ◽  
Zhenbiao Yang
Keyword(s):  
Grain Size ◽  
Cell Division ◽  
Grain Yield ◽  
Molecular Mechanisms ◽  
Grain Filling ◽  
High Yield ◽  
Rice Grain ◽  
Rop Gtpase ◽  
Key Factor ◽  
Grain Width

Grain size is a key factor for determining grain yield in crops and is a target trait for both domestication and breeding, yet the mechanisms underlying the regulation of grain size are largely unclear. Here we show that the grain size and yield of rice (Oryza sativa) is positively regulated by ROP GTPase (Rho-like GTPase from plants), a versatile molecular switch modulating plant growth, development, and responses to the environment. Overexpression of rice OsRac1ROP not only increases cell numbers, resulting in a larger spikelet hull, but also accelerates grain filling rate, causing greater grain width and weight. As a result, OsRac1 overexpression improves grain yield in O. sativa by nearly 16%. In contrast, down-regulation or deletion of OsRac1 causes the opposite effects. RNA-seq and cell cycle analyses suggest that OsRac1 promotes cell division. Interestingly, OsRac1 interacts with and regulates the phosphorylation level of OsMAPK6, which is known to regulate cell division and grain size in rice. Thus, our findings suggest OsRac1 modulates rice grain size and yield by influencing cell division. This study provides insights into the molecular mechanisms underlying the control of rice grain size and suggests that OsRac1 could serve as a potential target gene for breeding high-yield crops.

scholarly journals Rootstock Effects on Growth, Cell Number, and Cell Size of `Gala' Apples

2004 ◽  
Vol 129 (1) ◽  
pp. 37-41 ◽  
Author(s):  
Yahya K. Al-Hinai ◽  
Teryl R. Roper
Keyword(s):  
Cell Division ◽  
Cell Size ◽  
Agricultural Research ◽  
Fruit Size ◽  
Cell Number ◽  
Fruit Growth ◽  
Research Station ◽  
Full Bloom ◽  
Final Size ◽  
Load Effects

The effects of rootstock on growth of fruit cell number and size of `Gala' apple trees (Malus domestica Borkh) were investigated over three consecutive seasons (2000-02) growing on Malling 26 (M.26), Ottawa-3, Pajam-1, and Vineland (V)-605 rootstocks at the Peninsular Agricultural Research Station near Sturgeon Bay, WI. Fruit growth as a function of cell division and expansion was monitored from full bloom until harvest using scanning electron microscopy (SEM). Cell count and cell size measurements showed that rootstock had no affect on fruit growth and final size even when crop load effects were removed. Cell division ceased about 5 to 6 weeks after full bloom (WAFB) followed by cell expansion. Fruit size was positively correlated (r2 = 0.85) with cell size, suggesting that differences in fruit size were primarily a result of changes in cell size rather than cell number or intercellular space (IS).

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