Reflexion and absorption of solar radiation by flowering canopies of oil-seed rape (<i>Brassica napus</i> L.)

Yates, David J.; Steven, M. D.

doi:10.1017/s0021859600081703

Cited by 42 publications

(22 citation statements)

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“…The reflection of incident PAR during flowering was proportional to the number of petals present per unit area, as suggested by Yates & Steven (1987). However, absorption of PAR by the floral canopy only had a significant effect on light penetration when the complete floral layer had formed.…”

Section: Discussionmentioning

confidence: 86%

Physiological assessment of apetalous flowers and erectophile pods in oilseed rape (Brassica napus)

Fray¹,

Evans²,

Lydiate³

et al. 1996

J. Agric. Sci.

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S U M M A R YThe transmission of solar radiation within the crop canopies of oilseed rape is decreased both by the plant's yellow petals during flowering, and by the horizontal posture of the pods once they are formed. The significance of each of these morphologies was assessed, in the 1991/92 and 1992/93 growing seasons, by comparing the performances of an apetalous breeding line (N-o-112) and one with erectophile pods (N-5-130) with two conventional commercial genotypes (Falcon and Tapidor).The apetalous floral layer of line N-o-112 reflected and absorbed significantly less radiation than those of the conventional, petalled genotypes. This resulted in a greater transmission of photosynthetically active radiation (PAR) to the leaf and bract canopy situated below. At peak flowering, 70% more PAR was transmitted through the apetalous floral layer.The erectophile pods of line N-5-130 were angled 20-25° further from the horizontal than the conventional genotypes. The extinction coefficient (K) of its pod layer during late pod growth ranged from 035 to 0-44 as compared to 045 to 055 in the commercial varieties. Line N-5-130 carried a greater proportion of its total fertile pod number in the lower regions of the pod canopy compared to the two conventional genotypes. It also had a greater overall mean number of seeds per pod, and the number decreased proportionately less with depth in the canopy. The line was thus better able to maintain a higher photosynthetic area and to sustain pod and seed growth at the lower levels of the crop canopy than the conventional, commercial varieties. The potential physiological effects of apetalous flowers and erectophile pods are considered to be sufficiently beneficial for their introgression into near-isogenic lines to be pursued.i M T P o n i i r n n M termine the effect of the apetalous morphology on i N i K U U U C i i u w s e e d y i e , d T h e y c o n c l u d e d t h a t t h e character would Yield potential in oilseed rape (Brassica napus L.) be of most benefit in European winter varieties, which is determined by pre-anthesis dry matter (DM) flower more profusely. accumulation (Mendham et al. 1981), whilst the Chapman et al. (1984) reported that a dense pod realisation of this potential is dependent upon post-canopy greatly restricted radiation penetration during anthesis photosynthesis, and the translocation of pod filling, with only 6% of incident PAR reaching assimilates to the seed (Evans 1984). Radiation the base of the pod layer. Shading of the lower pods transmission to the leaf canopy during flowering is by the upper pods reduced their photosynthetic rate, reduced by the highly reflective and absorptive yellow induced higher pod and seed abortion and contributed floral layer. Chapman et al. (1984) found that this to low seed yields in the basal layer of the pod canopy resulted in only 24 and 7% of incident PAR reaching (Mendham et al. 1981). Poor radiation transmission the base of the floral layer at early and late flowering through the pod canopy may be caused by th...

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Section: Discussionmentioning

confidence: 86%

Physiological assessment of apetalous flowers and erectophile pods in oilseed rape (Brassica napus)

Fray¹,

Evans²,

Lydiate³

et al. 1996

J. Agric. Sci.

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“…In Brassica species, mutants have been observed which show increased petals, reduced petals, or complete absence of petals (apetalous) (Singh, 1961a,b; Cours and Williams, 1977; Buzza, 1983; Lü and Fu, 1990; Fray et al, 1997). Apetalous genotypes may be more efficient in photosynthesis and reallocation of assimilates because the yellow petal layer of Brassica oilseed crops reflects a large part of the photosynthetically active radiation (Chapman et al, 1984; Yates and Steven, 1987; Mendham et al, 1991; Fray et al, 1996; Jiang and Becker, 2001a). Moreover, apetalous types may avoid some diseases, especially stem rot caused by Sclerotinia sclerotiorum (Lib.)…”

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confidence: 99%

Inheritance of Apetalous Flowers in a Mutant of Oilseed Rape

Jiang

Becker

2003

Crop Science

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Oilseed rape (Brassica napus L.) genotypes with reduced petal size are thought to have advantages in photosynthetic capacity and in disease resistance. This study was conducted to analyze the inheritance of a completely apetalous mutant that was induced by mutagenic treatment. The mutant ap‐Tengbe was crossed with the German winter rapeseed cultivar Falcon. The F1, the F2, and both backcrosses including reciprocal generations were grown in field experiments at Göttingen, Germany, in 1997‐1998 and at Hangzhou, China, in 1998‐1999. The apetalous character of ap‐Tengbe is regulated by an interaction of cytoplasmic genes and two pairs of nuclear genes. Completely apetalous flowers are only expressed in genotypes with the ap cytoplasm and two homozygous recessive genes. In conclusion, the mutant ap‐Tengbe is useful to produce completely apetalous genotypes, but cytoplasmic effects have to be considered.

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“…Current challenges in using remote sensing and machine learning to identify crops include the availability of data of sufficient spectral, temporal and spatial resolution and the capacities to recognise field boundaries despite drop shadows and other confounding patterns when using self-organising maps (Kohonen, 2001). When satellites with suitable sampling frequency and the right sensors become available (e.g., yellow sensor with 570-590 nm wavelength (Yates & Steven, 1987) and weekly sampling given the likelihood of cloud cover, especially in England), our methods in conjunction with remote sensing data may, in the future, be developed to survey wide areas and to extend our understanding of the extent to which bee colonies are exposed to massflowering crops such as OSR.…”

Section: Discussionmentioning

confidence: 99%

Determining the foraging potential of oilseed rape to honey bees using aerial surveys and simulations

Schürch

Couvillon

Ratnieks

2015

Journal of Apicultural Research

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The modern agricultural landscape is characterised by large areas of monoculture, including fields of mass-flowering crops. These may benefit bees by providing abundant forage, but may cause harm if the fields are treated with insecticides. Here, we investigated the potential exposure of honeybee colonies to pesticides in flowering oilseed rape (OSR) in England using a combination of aerial photographs and geographical modelling. Aerial photographs were used to detect and map fields of blooming OSR in eight 20 Â 20 kilometers 2 areas across England where OSR is grown. We determined the distance to the nearest OSR field for randomly chosen positions (i.e., potential hive locations) using a digital map made of each area. The proportion of colonies within foraging range to the nearest OSR field in each area was then calculated using published data on honeybee foraging distances obtained by waggle dance decoding. We found that the distribution of distances to the nearest OSR field varied greatly among study areas, ranging from almost all colonies being within range to almost all being out of range (6-79% were within median foraging distance). In one study area, we examined changes over a 4-year period and found little year-to-year variation due to crop rotation (23-36% within median foraging distance). Our specific results show that exposure in England to OSR and to any chemicals used in treatment varies greatly among areas. Overall, our methodology provides a novel way of quantifying the exposure of bee colonies or other central place foragers to a particular crop or land-type at a landscape level.Determinació n del potencial de pecoreo de la colza para las abejas melíferas mediante reconocimientos aé reos y simulaciones El paisaje agrícola moderno se caracteriza por extensas áreas de monocultivo, incluyendo campos de cultivos de floració n masiva. Éstos pueden beneficiar a las abejas al proporcionar alimento abundante, pero pueden causar daño si los campos son tratados con insecticidas. Aquí se investigó la posible exposició n de las colonias de abejas de miel a la floració n de la colza (OSR por sus siglas en inglés) en Inglaterra mediante el uso de una combinació n de fotografías aéreas y de modelado geográfico. Se usaron fotografías aéreas para detectar y mapear campos de OSR en ocho áreas de 20 x 20 km a lo largo de Inglaterra donde se cultiva la colza. Se determinó la distancia al campo de OSR más cercano desde posiciones escogidas aleatoriamente (es decir, localizaciones potenciales de colmenas) utilizado un mapa digital hecho para cada área. La proporció n de colonias dentro del rango de pecoreo del campo de colza más cercano se calculó entonces a partir de los datos publicados sobre las distancias de pecoreo de las abejas melíferas, obtenidas mediante la decodificació n de la danza de las abejas. Encontramos que la distribució n de distancias al campo de colza más cercano varió mucho entre las áreas de estudio, oscilando desde casi todas las colonias dentro del rango, a casi todas fuera del rango (6% -79% ...

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Reflexion and absorption of solar radiation by flowering canopies of oil-seed rape (Brassica napus L.)

Cited by 42 publications

References 9 publications

Physiological assessment of apetalous flowers and erectophile pods in oilseed rape (Brassica napus)

Physiological assessment of apetalous flowers and erectophile pods in oilseed rape (Brassica napus)

Inheritance of Apetalous Flowers in a Mutant of Oilseed Rape

Determining the foraging potential of oilseed rape to honey bees using aerial surveys and simulations

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