Light quality (red:far-red ratio): does it affect photosynthetic activity, net CO2 assimilation, and morphology of young white clover leaves?

1999 ◽  
Vol 77 (10) ◽  
pp. 1425-1431 ◽  
Author(s):  
V. Heraut-Bron ◽  
C. Robin ◽  
C. Varlet-Grancher ◽  
D. Afif ◽  
A. Guckert
2016 ◽  
Vol 44 (1) ◽  
pp. 25-33 ◽  
Author(s):  
Anita Barbara SCHROETER-ZAKRZEWSKA ◽  
Klaudia BOROWIAK ◽  
Agnieszka WOLNA-MARUWKA

Geranium plants were cultivated in a growth chamber with different light quality and microorganism inoculation conditions. The long-term effect of irradiance quality (LED and fluorescent) as well as two types of microorganism treatments on photosynthetic activity parameters was examined. The maximum reached values of net photosynthesis rate (PN), stomatal conductance (gs), transpiration rate (E) and intercellular CO2 concentration (Ci) were afterwards measured in plants cultivated under six colours of light – white, white-blue, blue, red, red-blue and green – emitted by two types of lamp: LED and fluorescent. Two types of microorganism treatments were used: BAF1 created in the Department of General and Environmental Microbiology and the commonly used Effective Microorganisms (EM) biopreparation. A highest level of PN were found in plants after cultivation under white-blue light (both – fluorescent and LED) and treated by BAF1. The positive effect of EM was only noted in the case of plants cultivated under blue-red fluorescent light. Considering plants without microbial inoculation the highest levels were recorded in plants under red and blue light. The comparison of the effect of light quality revealed that in all colours a higher or similar level of net photosynthetic rate was noted in plants under LEDs. Mostly the higher photosynthetic activity was connected with higher stomatal opening as well as with higher transpiration rate, which is especially true for plants cultivated under red and blue LED light.


1983 ◽  
Vol 73 (1) ◽  
pp. 117-128 ◽  
Author(s):  
J. E. Sheehy ◽  
C. Vazzana ◽  
F. R. Minchin

2000 ◽  
Vol 77 (10) ◽  
pp. 1425-1431 ◽  
Author(s):  
V Heraut-Bron ◽  
C Robin ◽  
C Varlet-Grancher ◽  
D Afif ◽  
A Guckert

We assessed the effects of red:far-red (R:FR) ratio on net CO2 assimilation, photosynthetic activity, and morphology of young white clover leaves developed under a simulated canopy light environment. Isolated cuttings of Trifolium repens L. were grown in controlled conditions under two irradiances in combination with two R:FR ratios. We used far-red light emitting diodes to reduce the R:FR ratio on leaves that were successively developing on the main stolon and were subject to strong competition for light within a sward. A leaf that developed under a low R:FR ratio had a lower chlorophyll content than the controls. However, this change had no consequences on the net CO2 assimilation rate and on the biomass allocated to shoots. The low R:FR ratio modified the leaf morphology by increasing the leaf area. A leaf that developed in lower irradiance had a lower net CO2 assimilation rate and a greater leaf area and petiole length than leaves that developed in higher irradiance. Therefore, irradiance was the main factor limiting the leaf CO2 assimilation under a canopy. Capture of light by clover leaves was improved by FR light only via modifications of leaf morphology, because there were no significant effects of FR light on photosynthesis.


Author(s):  
Н.Н. Лазарев ◽  
О.В. Кухаренкова ◽  
А.Р. Тяжкороб ◽  
С.М. Авдеев

Научный обзор посвящён использованию клевера ползучего в пастбищном хозяйстве различных стран мира. В Европе и Новой Зеландии этот вид является основным бобовым компонентом пастбищных травосмесей. Его наиболее часто высевают в смеси с райграсом пастбищным, что обеспечивает получение кормов с благоприятным сахаропротеиновым отношением. Он превосходит все другие бобовые травы по устойчивости к частому использованию благодаря тому, что его стебли стелются по поверхности почвы и при пастьбе не стравливаются даже овцами и лошадьми. Побеги и часть листьев клевера ползучего лежат на поверхности почвы, и благодаря им растения быстро восстанавливают фотосинтетическую деятельность после стравливания. Травостои с участием клевера ползучего при благоприятных условиях увлажнения способны выдерживать пять-семь стравливаний за сезон. Клевер ползучий превосходит другие виды трав по питательности и хорошо поедается животными, поскольку его урожай представлен преимущественно листьями и в некоторой степени — цветоносами. Клевер ползучий обладает высокой азотфиксирующей способностью, ежегодно накапливая в надземной массе 100–300 кг/га азота; он менее чувствителен к кислой реакции почвенного раствора, чем люцерна, козлятник, эспарцет и клевер луговой, может успешно расти на средних по плодородию почвах. Имея слабую корневую систему, клевер ползучий устойчивее других видов трав к близкому залеганию грунтовых вод. Высокая способность к вегетативному размножению благодаря ползучим надземным побегам позволяет ему сохраняться в составе фитоценозов десятки лет. На пастбищах немаловажное значение имеет и семенное размножение. Некоторое количество головок клевера может достигать полной спелости и распространяться животными вместе с экскрементами. К недостаткам клевера ползучего следует отнести его невысокую засухоустойчивость. При неблагоприятных метеорологических условиях он также может изреживаться в период перезимовки. This review reports on white clover cultivation worldwide. The crop is a common legume component of pasture ecosystems in Europe and New Zealand. It is usually seeded with perennial ryegrass providing forage with optimal sugar-to-protein ratio. White clover exceeds the rest of legume grasses in longevity, its stems lay on soil surface and are not completely grazed even by sheep and horses. Since shoots and sometimes leaves also lay on soil surface, plants recover their photosynthetic activity quite fast after grazing. White clover ecosystems survive five-seven grazings per season under optimal water supply. The crop exceeds other grasses in nutritional value and has high palatability. White clover shows high nitrogen-fixing capacity accumulating 100–300 kg ha-1 of nitrogen in its shoots annually. It grows well on moderately fertile soils and tolerates low soil pH better than alfalfa, eastern goat’s rue, and red clover. Poor root system makes white clover more resistant to groundwater occurrence. It grows in grasslands for decades due to high ability to vegetative reproduction but can also propagate by seeds. Several plants reach their full maturity and spread by animals via excrements. Its disadvantage is low drought-resistance. Under unfavorable conditions white clover overwinters poorly.


1994 ◽  
Vol 91 (2) ◽  
pp. 322-328 ◽  
Author(s):  
M. Sattin ◽  
M. C. Zuin ◽  
I. Sartorato
Keyword(s):  

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