GROWTH HABIT AND ROW WIDTH EFFECTS ON LEAF AREA DEVELOPMENT AND LIGHT INTERCEPTION OF FIELD BEANS

1979 ◽  
Vol 59 (1) ◽  
pp. 191-199 ◽  
Author(s):  
T. R. GARDINER ◽  
L. E. CRAKER ◽  
D. M. VIETOR

Leaf area development and percent interception of photosynthetically-active radiation (PAR) were measured to compare a determinate, bush cultivar with an indeterminate, climbing or pole cultivar of Phaseolus vulgaris L. in a short season environment. Each cultivar was grown at a wide (91 cm) and narrow (45.5 cm) interrow spacing to evaluate the growth habit effects under currently recommended plant spacings. Percent PAR interception and leaf area index (LAI) were determined on five sampling dates and PAR penetrating through the canopy was recorded on four of those dates. A large reduction of LAI of the bush cultivar and continued expansion of leaves in the upper portion of the pole canopy resulted in a greater percentage of PAR interception by the pole cultivar than by the bush cultivar at 72 days after planting. The taller, unlodged vine-type canopy of the pole cultivar intercepted nearly 50% more PAR than the bush cultivar when the LAI of the two cultivars was comparable at 96 days. The continued leaf expansion and late initiation of pod filling limited the duration of rapid pod filling of the pole cultivar in the short season environment. LAI and percent interception of PAR by the bush cultivar were greater at the 45.5-cm than at the 91-cm spacing at 41 and 54 days. The maximum LAI and percent interception were only 3.2 and 82%, respectively, for the 91-cm spacing of the bush cultivar. LAI of the 45.5-cm spacing of the bush cultivar was reduced to a value less than that of the 91-cm spacing from 54 to 72 days, but percent interception by the 45.5-cm spacing was still greater. Percent interception of PAR at 41 days was greater at the 45.5-cm spacing than at the 91-cm spacing of the pole bean, but interrow spacing did not affect LAI or percent interception on the other dates.

Crop Science ◽  
1998 ◽  
Vol 38 (3) ◽  
pp. 827-834 ◽  
Author(s):  
I. C. Madakadze ◽  
B. E. Coulman ◽  
P. Peterson ◽  
K. A. Stewart ◽  
R. Samson ◽  
...  

2019 ◽  
Vol 33 (5) ◽  
pp. 620-632
Author(s):  
José A. Clavijo Michelangeli ◽  
Jaumer Ricaurte ◽  
Thomas R. Sinclair ◽  
Idupulapati M. Rao ◽  
Stephen E. Beebe

1970 ◽  
Vol 48 (10) ◽  
pp. 1801-1804 ◽  
Author(s):  
D. F. W. Pollard

Different shoot types in aspen crowns carried leaves of different ages; leaders continued to produce leaves until early August and always carried some young leaves, whereas short shoots completed development by mid-June. Development of foliage on long shoots was intermediate between that on leaders and short shoots. Leaf area index of the 6-year-old stand reached a maximum of 2.4, of which 2.1 was contributed by short-shoot foliage. The rest was formed by leaders and long shoots. Young leaves on leaders and long shoots were not sufficient to influence total production in the stand appreciably, even though young aspen leaves may have high photosynthetic efficiencies. These young leaves could, however, influence height growth and lateral development of the canopy.


1995 ◽  
Vol 46 (1) ◽  
pp. 99 ◽  
Author(s):  
F Giunta ◽  
R Motzo ◽  
M Deidda

A field experiment was carried out in Sardinia (Italy) on durum wheat to analyse the effects of different moisture treatments, irrigated (I), rainfed (R) and stressed (S), on leaf area index (LAI), radiation intercepted (Q) and water use (WU), efficiency of conversion of radiation and water into dry matter (RUE and WUE), nitrogen uptake and carbon and nitrogen partitioning in the above-ground part of the plant. In the period between beginning of stem elongation and heading, drought affected the maximum LA1 in the most stressed treatment (4.7 in S v. about 6.9 in R and I), but not Q and WU. RUE was also lowered by drought in this period (0.68 in S v. about 0.95 g MJ-1 in R and I) as a reduced biomass was recorded in S at heading (528gm-2 in S v. 777 g m-2 on average in R and I). In contrast with the previous period, the reduction in LA1 between heading and maximum ear weight (MEW) determined a significant reduction in Q and WU, WUE and RUE, resulting, ultimately, in notable differences in the total biomass produced until MEW (1203, 930 and 546 gm-2 in I, R and S respectively). The amount of stem reserves relocated to the grain decreased as the level of stress increased, going from 223gm-2 in I to 9gm-2 in S and was accumulated almost entirely (from 76% of the total in I to 100% in S), in the post-heading period. Nitrogen percentage was not affected by the treatments applied apart from the higher values in stem and flag leaf in S later in the growing season due to an inhibition of nitrogen translocation in S. The total nitrogen uptake was lower in S (12.3gm-2) than in I (16.6gm-2) only as a consequence of the different dry matter accumulation patterns. The importance of WUE in this type of Mediterranean environment is discussed, with particular concern to the key role of modulation of leaf area development through the growing season.


2011 ◽  
Vol 62 (12) ◽  
pp. 1045 ◽  
Author(s):  
A. M. Massignam ◽  
S. C. Chapman ◽  
G. L. Hammer ◽  
S. Fukai

Nitrogen (N) limitation reduces canopy carbon assimilation by directly reducing leaf photosynthesis, and by developmentally reducing the rate of new leaf area development and accelerating leaf senescence. Effective use of N for biomass production under N limitation may be considered to be a result of a trade-off between the use of N to maintain high levels of specific leaf nitrogen (SLN the amount of N per unit leaf area) for high photosynthetic rate versus using N to maintain leaf area development (leaf area index – LAI). The objective here is to compare the effects of N supply on the dynamics of LAI and SLN for two crops, maize (Zea mays L.) and sunflower (Helianthus annuus L.) that contrast in the structure and development of their canopy. Three irrigated experiments imposed different levels of N and plant density. While LAI in both maize and sunflower was reduced under N limitation, leaf area development was more responsive to N supply in sunflower than maize. Observations near anthesis showed that sunflower tended to maintain SLN and adjust leaf area under reduced N supply, whereas maize tended to maintain leaf area and adjust SLN first, and, when this was not sufficient, SLN was also reduced. The two species responded differently to variation in N supply, and the implication of these different strategies for crop adaptation and management is discussed.


1987 ◽  
Vol 38 (6) ◽  
pp. 983 ◽  
Author(s):  
RA Richards ◽  
TF Townley-Smith

Genotypes, chosen because of their variation in flowering, tillering and early leaf growth, were evaluated in 1 m long tubes in a glasshouse. These traits were selected for two reasons: firstly, because it was presumed they influence leaf area development and hence the water use, harvest index and yield of droughted wheat; secondly, because they are amenable to genetic manipulation and therefore can be selected in a breeding program. Four drought treatments were imposed in each of two seasons. The treatments and cultural conditions simulated droughts encountered by field-grown crops. Grain yield varied according to the amount of growth and water use before and after anthesis in relation to soil water supply. In the wettest treatments where plants had adequate water up to anthesis but were droughted thereafter (akin to a wet mediterranean-type environment), grain yield was positively associated with the amount of preanthesis growth. In the drier treatments, where droughts were sustained from before anthesis, genotypes having traits that reduced leaf area index saved more water for use after anthesis and had a higher harvest index and grain yield. However, pre-anthesis growth was also important, as it was estimated that in the driest treatments up to 60% of the grain dry weight was formed from reserves present at anthesis. These reserves represented up to 15% of the above-ground biomass at anthesis. Harvest index (y) was a nonlinear function of the proportion of water used after anthesis (x), y = 0.10 + 0.13 ln(x), r2 = 0.82 (P < 0.01).The determinate tillering or 'uniculm' wheats, although having some advantages over conventional tillering lines when sown at the same density, were largely indistinguishable from conventional wheats in their water use pattern when sown at twice the density. However, at both densities they had a higher stem weight per unit length and a higher specific leaf weight than conventional wheats, and this resulted in them having a lower harvest index and grain yield. These pleiotropic effects may reduce the possible advantages of these wheats, that is a reduced maximum leaf area and no sterile tillers, in dry environments.


1995 ◽  
Vol 46 (5) ◽  
pp. 845
Author(s):  
SP Milroy ◽  
PJ Goyne

A model to simulate leaf area development for barley at the whole plant level was constructed. Data for leaf area development in the absence of soil water stress were collected from irrigated field trials grown at Hermitage Research Station, near Warwick, Queensland, in 1990. The response of leaf area expansion to soil water status was measured in a glasshouse trial. In the model, green leaf area per plant (GPLA) is derived as the difference between total leaf area produced per plant (TPLA) and senesced leaf area (SPLA). TPLA and SPLA are described by logistic functions of thermal time. Two types of senescence are included: that due to ageing of the whole plant (ontogenetic senescence) and senescence associated with the development of large canopies (light-induced senescence). The onset of ontogenetic senescence is linked to anthesis, whereas light-induced senescence occurs if the leaf area index of the crop exceeds 5.5. Leaf expansion of plants in pots varying in the fraction of transpirable soil water available (FTSW) was compared with leaf expansion of those in well-watered pots three times per week. The relationship between relative leaf expansion (RLE) and FTSW was described by a logistic function (r2 = 0.96). A 50% reduction in RLE occurred when FTSW = 0.34. Similarly, a logistic function described the relationship between relative transpiration (RT) and FTSW (r2 = 0.96). A 50% reduction in RT occurred when FTSW = 0.17. Potential leaf expansion as predicted by the non-stressed model was reduced in response to moisture stress via a ramp function relating RLE to RT. The model gave an unbiased prediction of the leaf area dynamics for 21 rainfed and irrigated crops of barley grown in southern Queensland between 1986 and 1993 (RMSD = 1.09 m2 m-2, r2 = 0.75, n = 76). Precision may have been reduced by the lack of information available on parameters for soil water balance when barley is grown on a range of soil types.


1973 ◽  
Vol 81 (3) ◽  
pp. 449-453 ◽  
Author(s):  
B. A. C. Enyi

SUMMARYIn each of the crops studied, weeding increased grain yield, weeding 2 weeks after sowing being better than weeding either four or eight weeks after sowing and weeding two and four weeks after sowing being better than weeding either two and eight weeks or four and eight weeks aftersowing. Weeding thrice (two, four and eight weeks after sowing) was significantly superior to all the other weeding treatments. Weeding increased leaf area index, dry weight of side and mainstem and number of mature pods at harvest in green gram and cowpeas. In sorghum, apart from increasing leaf area index, it also increased the length of ears and grain weight per unit lengthof ear. The weeding treatments affected grain yield in cowpeas and green gram due totheir influence on leaf area development, development of the main and side stems and on the number of mature pods produced at harvest. The effect of the weeding treatments on grain yield of sorghum was due to their influence on leaf area development, length of ear and grain weight perunit length of ear.


1995 ◽  
Vol 46 (5) ◽  
pp. 845
Author(s):  
SP Milroy ◽  
PJ Goyne

A model to simulate leaf area development for barley at the whole plant level was constructed. Data for leaf area development in the absence of soil water stress were collected from irrigated field trials grown at Hermitage Research Station, near Warwick, Queensland, in 1990. The response of leaf area expansion to soil water status was measured in a glasshouse trial. In the model, green leaf area per plant (GPLA) is derived as the difference between total leaf area produced per plant (TPLA) and senesced leaf area (SPLA). TPLA and SPLA are described by logistic functions of thermal time. Two types of senescence are included: that due to ageing of the whole plant (ontogenetic senescence) and senescence associated with the development of large canopies (light-induced senescence). The onset of ontogenetic senescence is linked to anthesis, whereas light-induced senescence occurs if the leaf area index of the crop exceeds 5.5. Leaf expansion of plants in pots varying in the fraction of transpirable soil water available (FTSW) was compared with leaf expansion of those in well-watered pots three times per week. The relationship between relative leaf expansion (RLE) and FTSW was described by a logistic function (r2 = 0.96). A 50% reduction in RLE occurred when FTSW = 0.34. Similarly, a logistic function described the relationship between relative transpiration (RT) and FTSW (r2 = 0.96). A 50% reduction in RT occurred when FTSW = 0.17. Potential leaf expansion as predicted by the non-stressed model was reduced in response to moisture stress via a ramp function relating RLE to RT. The model gave an unbiased prediction of the leaf area dynamics for 21 rainfed and irrigated crops of barley grown in southern Queensland between 1986 and 1993 (RMSD = 1.09 m2 m-2, r2 = 0.75, n = 76). Precision may have been reduced by the lack of information available on parameters for soil water balance when barley is grown on a range of soil types.


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