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Overexpression of a Potato Sucrose Synthase Gene in Cotton Accelerates Leaf Expansion, Reduces Seed Abortion, and Enhances Fiber Production 被引量:36
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作者 Shou-Min Xu Elizabeth Brill +2 位作者 Danny J. Llewellyn Robert T. Furbank Yong-Ling Ruan 《Molecular Plant》 SCIE CAS CSCD 2012年第2期430-441,共12页
Sucrose synthase (Sus) is a key enzyme in the breakdown of sucrose and is considered a biochemical marker for sink strength, especially in crop species, based on mutational and gene suppression studies. It remains e... Sucrose synthase (Sus) is a key enzyme in the breakdown of sucrose and is considered a biochemical marker for sink strength, especially in crop species, based on mutational and gene suppression studies. It remains elusive, however, whether, or to what extent, increase in Sus activity may enhance sink development. We aimed to address this question by expressing a potato Sus gene in cotton where Sus expression has been previously shown to be critical for normal seed and fiber development. Segregation analyses at T1 generation followed by studies in homozygous progeny lines revealed that increased Sus activity in cotton (1) enhanced leaf expansion with the effect evident from young leaves emerging from shoot apex; (2) improved early seed development, which reduced seed abortion, hence enhanced seed set, and (3) promoted fiber elongation. In young leaves of Sus overexpressing lines, fructose concentrations were significantly increased whereas, in elongating fibers, both fructose and glucose levels were increased. Since hexoses contribute little to osmolality in leaves, in contrast to developing fibers, it is concluded that high Sus activity promotes leaf development independently of osmotic regulation, probably through sugar signaling. The analyses also showed that doubling the Sus activity in 0-d cotton seeds increased their fresh weight by about 30%. However, further increase in Sus activity did not lead to any further increase in seed weight, indicating an upper limit for the Sus overexpression effect. Finally, based on the observed additive effect on fiber yield from increased fiber length and seed number, a new strategy is proposed to increase cotton fiber yield by improving seed development as a whole, rather than solely focusing on manipulating fiber growth. 展开更多
关键词 cotton fiber INVERTASE leaf expansion seed abortion seed development sucrose synthase sugar signaling.
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Determination of the Photoperiod-Sensitive Inductive Phase in Maize with Leaf Numbers and Morphologies of Stem Apical Meristem 被引量:4
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作者 WU Lian-cheng WANG Tie-gu +4 位作者 KU Li-xia HUANG Qun-ce SUN Zhao-hui XIA Zhong-liang CHEN Yan-hui 《Agricultural Sciences in China》 CAS CSCD 2008年第5期554-560,共7页
It is vital to determine the effective photoperiods of maize for making full use of tropical germplasm, which is the foundation for determining the effect of latitude and planting date on the development of photoperio... It is vital to determine the effective photoperiods of maize for making full use of tropical germplasm, which is the foundation for determining the effect of latitude and planting date on the development of photoperiod-sensitive maize cultivars. The objective of this study is to determine the photoperiod-sensitive inductive phase using reciprocal transfer between long- day (LD) (15 h d^-1) and short-day conditions (SD) (9 h d^-1). For Huangzao 4 and CML288, days to tassel and pollen shedding were recorded, and stem apical meristems (SAM) were observed by a laser scanning confocal microscope. The results show that the seedlings are insensitive to photoperiod when they are very young (juvenile). However, after this period, LD delays flowering and increases the leaf numbers below the inflorescence, and the length of the interval of the photoperiod-sensitive inductive phase is longer under LD conditions than under SD conditions. Transferred from SD to LD, plants show a sudden decrease in leaf numbers once sufficient SD has been received for flower commitment. While transferred from LD to SD, plants have a continuous increase in leaf numbers during the photoperiod sensitive inductive phase under LD conditions. At the same time, when plants are competent to flowers, the obvious morphology is the elongation of maize SAM. There is an obvious variance of the photoperiod sensitive phase under LD and SD conditions in different maize. 展开更多
关键词 MAIZE PHOTOPERIOD FLOWERING LSCM stem apical meristem (SAM) new full expansion leaf
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Seven Things We Think We Know about Auxin Transport 被引量:32
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作者 Wendy Ann Peer Joshua J. Blakeslee +1 位作者 Haibing Yang Angus S. Murphy 《Molecular Plant》 SCIE CAS CSCD 2011年第3期487-504,共18页
Polar transport of the phytohormone auxin and the establishment of localized auxin maxima regulate em- bryonic development, stem cell maintenance, root and shoot architecture, and tropic growth responses. The past dec... Polar transport of the phytohormone auxin and the establishment of localized auxin maxima regulate em- bryonic development, stem cell maintenance, root and shoot architecture, and tropic growth responses. The past decade has been marked by dramatic progress in efforts to elucidate the complex mechanisms by which auxin transport regulates plant growth. As the understanding of auxin transport regulation has been increasingly elaborated, it has become clear that this process is involved in almost all plant growth and environmental responses in some way. However, we still lack information about some basic aspects of this fundamental regulatory mechanism. In this review, we present what we know (or what we think we know) and what we do not know about seven auxin-regulated processes. We discuss the role of auxin transport in gravitropism in primary and lateral roots, phototropism, shoot branching, leaf expansion, and venation. We also discuss the auxin reflux/fountain model at the root tip, flavonoid modulation of auxin transport processes, and outstanding aspects of post-translational regulation of auxin transporters. This discussion is not meant to be exhaustive, but highlights areas in which generally held assumptions require more substantive validation. 展开更多
关键词 Auxin transport ABCB AUX1 PIN PHOTOTROPISM GRAVITROPISM fountain model shoot branching leaf expansion VENATION flavonoids.
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