Photosynthetic acclimation during low-light-induced leaf senescence in post-anthesis maize plants

Author(s):  
Han-Yu Wu ◽  
Li-An Liu ◽  
Lei Shi ◽  
Wang-Feng Zhang ◽  
Chuang-Dao Jiang
2021 ◽  
Vol 22 (8) ◽  
pp. 3936
Author(s):  
Ahmed G. Gad ◽  
Habiba ◽  
Xiangzi Zheng ◽  
Ying Miao

Leaf senescence, as an integral part of the final development stage for plants, primarily remobilizes nutrients from the sources to the sinks in response to different stressors. The premature senescence of leaves is a critical challenge that causes significant economic losses in terms of crop yields. Although low light causes losses of up to 50% and affects rice yield and quality, its regulatory mechanisms remain poorly elucidated. Darkness-mediated premature leaf senescence is a well-studied stressor. It initiates the expression of senescence-associated genes (SAGs), which have been implicated in chlorophyll breakdown and degradation. The molecular and biochemical regulatory mechanisms of premature leaf senescence show significant levels of redundant biomass in complex pathways. Thus, clarifying the regulatory mechanisms of low-light/dark-induced senescence may be conducive to developing strategies for rice crop improvement. This review describes the recent molecular regulatory mechanisms associated with low-light response and dark-induced senescence (DIS), and their effects on plastid signaling and photosynthesis-mediated processes, chloroplast and protein degradation, as well as hormonal and transcriptional regulation in rice.


Author(s):  
George Bawa ◽  
Guopeng Chen ◽  
Jianyi Shi ◽  
Chen Ping ◽  
Lingyang Feng ◽  
...  

2010 ◽  
Vol 61 (14) ◽  
pp. 4109-4122 ◽  
Author(s):  
Jasper J. L. Pengelly ◽  
Xavier R. R. Sirault ◽  
Youshi Tazoe ◽  
John R. Evans ◽  
Robert T. Furbank ◽  
...  

1985 ◽  
Vol 65 (4) ◽  
pp. 819-829 ◽  
Author(s):  
P. GIRARDIN ◽  
A. DELTOUR ◽  
M. TOLLENAAR

A prerequisite for an informed strategy regarding nitrogen application in maize (Zea mays L.) is a knowledge of the physiology of plant responses to nitrogen. This study consisted of two experiments on maize plants grown in pails. One experiment was conducted in controlled-environment growth rooms, the other was conducted in the field. N-deficient and control maize plants were evaluated for photosynthetic rate (P), chlorophyll content (CC), nitrogen content, and green leaf area; comparisons between these four parameters were made. During N starvation, rate of senescence (i.e. decrease in green leaf area) of the old leaves was higher in N-deprived plants than in control plants. P and CC of all leaves in the N-deficient treatment decreased during nitrogen withdrawal. After the deprivation period, when the plants were resupplied with N, senescence was delayed relative to control plants. The increase of CC in treatment plants was slower than the recovery of photosynthetic rate; in fact, CC was a poor indicator of photosynthetic activity. The delay in leaf senescence corresponded with regreening in leaves of N-deprived plants following N addition. This delay could be partly explained by an overcompensation in plant N requirement involving both a rapid increase in P, and a slower increase in CC. The effects of resupplying plants with nitrogen following a N-deprivation period lead us to believe that the observed leaf yellowing is actually a premature senescence which is reversible, and that a low N content is not the single causal factor of senescence.Key words: Chlorophyll content, leaf area, photosynthetic rate, Zea mays L.


Author(s):  
G.Y. Fan ◽  
J.M. Cowley

In recent developments, the ASU HB5 has been modified so that the timing, positioning, and scanning of the finely focused electron probe can be entirely controlled by a host computer. This made the asynchronized handshake possible between the HB5 STEM and the image processing system which consists of host computer (PDP 11/34), DeAnza image processor (IP 5000) which is interfaced with a low-light level TV camera, array processor (AP 400) and various peripheral devices. This greatly facilitates the pattern recognition technique initiated by Monosmith and Cowley. Software called NANHB5 is under development which, instead of employing a set of photo-diodes to detect strong spots on a TV screen, uses various software techniques including on-line fast Fourier transform (FFT) to recognize patterns of greater complexity, taking advantage of the sophistication of our image processing system and the flexibility of computer software.


Author(s):  
W. Lin ◽  
J. Gregorio ◽  
T.J. Holmes ◽  
D. H. Szarowski ◽  
J.N. Turner

A low-light level video microscope with long working distance objective lenses has been built as part of our integrated three-dimensional (3-D) light microscopy workstation (Fig. 1). It allows the observation of living specimens under sufficiently low light illumination that no significant photobleaching or alternation of specimen physiology is produced. The improved image quality, depth discrimination and 3-D reconstruction provides a versatile intermediate resolution system that replaces the commonly used dissection microscope for initial image recording and positioning of microelectrodes for neurobiology. A 3-D image is displayed on-line to guide the execution of complex experiments. An image composed of 40 optical sections requires 7 minutes to process and display a stereo pair.The low-light level video microscope utilizes long working distance objective lenses from Mitutoyo (10X, 0.28NA, 37 mm working distance; 20X, 0.42NA, 20 mm working distance; 50X, 0.42NA, 20 mm working distance). They provide enough working distance to allow the placement of microelectrodes in the specimen.


Author(s):  
Ray Keller

The amphibian embryo offers advantages of size, availability, and ease of use with both microsurgical and molecular methods in the analysis of fundamental developmental and cell biological problems. However, conventional wisdom holds that the opacity of this embryo limits the use of methods in optical microscopy to resolve the cell motility underlying the major shape-generating processes in early development.These difficulties have been circumvented by refining and adapting several methods. First, methods of explanting and culturing tissues were developed that expose the deep, nonepithelial cells, as well as the superficial epithelial cells, to the view of the microscope. Second, low angle epi-illumination with video image processing and recording was used to follow patterns of cell movement in large populations of cells. Lastly, cells were labeled with vital, fluorescent dyes, and their behavior recorded, using low-light, fluorescence microscopy and image processing. Using these methods, the details of the cellular protrusive activity that drives the powerful convergence (narrowing)


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