Linear relationship between phytochrome photoequilibrium and growth in plants under simulated natural radiation

Morgan, D. C.; Smith, Harry

doi:10.1038/262210a0

Cited by 202 publications

(116 citation statements)

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“…Phytochrome acts to detect mutual shading through the changed quality of natural radiation, and to redirect development appropriately (Holmes and Smith, 1975;Morgan and Smith, 1976;Smith, 1995). Plants can, through phytochrome-mediated photomorphogenesis, respond to both competitive (at high population density) and simulated-competition (through reduced red/ far-red ratio) environments by increasing stem extension (Morgan and Smith, 1976;Ballaré et al, 1990;Dale and Causton, 1992), internode elongation (Smith, 1982;Ballaré et al, 1988;Davis and Simmons, 1994;Huber, 1997) and petiole length Fig. 8.…”

Section: Discussionmentioning

confidence: 99%

The effect of population density on shoot morphology of herbs in relation to light capture by leaves

Sekimura

Koebernick

Лі

et al. 2000

Ecological Modelling

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Plants change their shapes, depending on their environment, for example, plant height increases with increasing population density. We examined the density-dependent plasticity in shoot morphology of herbs by analysing a mathematical model which identifies a number of key factors that influence shoot morphology, namely (i) solar radiation captured by leaves; (ii) shading from neighbouring plants; and (iii) utilisation efficiency of resource by leaves, stems and veins. An optimisation theory was used to obtain optimal shoot morphology in relation to maximal light capture by leaves, under trade-offs of resource partition among organs. We first evaluated the solar radiation flux per unit leaf area per day for different shoot forms. Our model predicts that the optimal internodal length of the stem that brings about the maximal light capture by leaves increases with plant population density, and this is consistent with experimental data. Moreover, our simple model can also be extended to explain the morphological plasticity in other herbs (i.e. stemless plants) that are different from our model plants with a stem. These findings illustrate how optimisation theory can be used for the analysis of plasticity in shoot morphology of plants in response to environmental changes, as well as the analysis of diversity in morphology.

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Section: Discussionmentioning

confidence: 99%

The effect of population density on shoot morphology of herbs in relation to light capture by leaves

Sekimura

Koebernick

Лі

et al. 2000

Ecological Modelling

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“…Scientists tested the hypothesis that far-red-enriched environments might inhibit germination so that seedlings would only emerge after covering vegetation died back or moved ( Cumming, 1963 ). Early studies on the abundant far-red wavelengths of canopy shade were shown to affect plant architecture by controlling stem elongation ( Morgan and Smith, 1976 ), leaf expansion, leaf hyponasty (leading to a more vertical orientation), petiole elongation, and apical dominance ( Ballare, 1999 ).…”

Section: Shade Responses To Deviations In Red/far-red Ratio and To Lomentioning

confidence: 99%

Contributions of green light to plant growth and development

Wang

Folta

2013

American J of Botany

207

119

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Light passing through or refl ected from adjacent foliage provides a developing plant with information that is used to guide specifi c genetic and physiological processes. Changes in gene expression underlie adaptation to, or avoidance of, the light-compromised environment. These changes have been well described and are mostly attributed to a decrease in the red light to far-red light ratio and/or a reduction in blue light fl uence rate. In most cases, these changes rely on the integration of red/far-red/blue light signals, leading to changes in phytohormone levels. Studies over the last decade have described distinct responses to green light and/or a shift of the blue-green, or red-green ratio. Responses to green light are typically low-light responses, suggesting that they may contribute to the adaptation to growth under foliage or within close proximity to other plants. This review summarizes the growth responses in artifi cially manipulated light environments with an emphasis on the roles of green wavebands. The information may be extended to understanding the infl uence of green light in shade avoidance responses as well as other plant developmental and physiological processes.

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“…Changes in the R to FR ratio perceived by phytochromes initiate a number of responses such as increased stem extension growth (Morgan and Smith, 1976), reduced branching (Deregibus et al, 1983), and accelerated leaf senescence (Rousseaux et al, 1999), which are collectively called the shade avoidance syndrome (Smith, 2000). In growing canopies, some of these changes anticipate competition for PPFD because R to FR signals caused by FR reflected on neighboring vegetation take place before mutual plant shading (Casal et al, 1986;Ballaré et al, 1987Ballaré et al, , 1990.…”

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confidence: 99%

Increased Phytochrome B Alleviates Density Effects on Tuber Yield of Field Potato Crops

et al. 2003

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The possibility that reduced photomorphogenic responses could increase field crop yield has been suggested often, but experimental support is still lacking. Here, we report that ectopic expression of the Arabidopsis PHYB (phytochrome B) gene, a photoreceptor involved in detecting red to far-red light ratio associated with plant density, can increase tuber yield in field-grown transgenic potato (Solanum tuberosum) crops. Surprisingly, this effect was larger at very high densities, despite the intense reduction in the red to far-red light ratios and the concomitant narrowed differences in active phytochrome B levels between wild type and transgenics at these densities. Increased PHYB expression not only altered the ability of plants to respond to light signals, but they also modified the light environment itself. This combination resulted in larger effects of enhanced PHYB expression on tuber number and crop photosynthesis at high planting densities. The PHYB transgenics showed higher maximum photosynthesis in leaves of all strata of the canopy, and this effect was largely due to increased leaf stomatal conductance. We propose that enhanced PHYB expression could be used in breeding programs to shift optimum planting densities to higher levels.The world population is predicted to reach 8 billion by 2025, and this, in combination with current trends in dietary composition, will result in a substantial increase of food demand. The ability to satisfy this demand will rely heavily on the genetic improvement of cultivated plants to increase yield potentials and/or yield stability (i.e. the constancy of performance; Khush, 2001). Although yield per unit area continues to increase for many crops, maximum yield is not showing such an obvious trend, and this has been interpreted as a result of yield potential approaching a ceiling, whereas yield stability continues to grow (Mann, 1999). Although some consider that this ceiling represents the highest physically attainable yield (Sinclair, 1993), others are more confident that incorporation of the current wealth of knowledge in plant biology will overcome the decreasing rate of increase in yield potential. However, genetic modifications that appear beneficial when analyzed at the cellular or plant level do not necessarily translate into higher yields in the field, either because of negative side effects or simply because they do not operate on the limitations under field conditions.As incident solar radiation penetrates the canopy of commercial crops, it suffers a gradual attenuation of the photosynthetic photon flux density (PPFD) and of the red (R) to far-red (FR) ratio (Holmes and Smith, 1977). Changes in the R to FR ratio perceived by phytochromes initiate a number of responses such as increased stem extension growth (Morgan and Smith, 1976), reduced branching (Deregibus et al., 1983), and accelerated leaf senescence (Rousseaux et al., 1999), which are collectively called the shade avoidance syndrome (Smith, 2000). In growing canopies, some of these changes anticipate com...

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Linear relationship between phytochrome photoequilibrium and growth in plants under simulated natural radiation

Cited by 202 publications

References 5 publications

The effect of population density on shoot morphology of herbs in relation to light capture by leaves

The effect of population density on shoot morphology of herbs in relation to light capture by leaves

Contributions of green light to plant growth and development

Increased Phytochrome B Alleviates Density Effects on Tuber Yield of Field Potato Crops

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