scholarly journals Relationship of Relative Leaf Growth Rate to Net Assimilation Rate and its Relevance to the Physiological Analysis of Plant Yield

Nature ◽  
1963 ◽  
Vol 200 (4909) ◽  
pp. 909-909 ◽  
Author(s):  
JOHN E. JACKSON
1987 ◽  
Vol 108 (1) ◽  
pp. 245-247 ◽  
Author(s):  
S. Singh ◽  
P. N. Gururaja Rao

In sugar cane, investigations made earlier (Singh & Gururaja Rao, 1985) have shown that high-yielding varieties have higher net assimilation rate than low-yielding types. Similarly, differences in progeny means for relative growth rate and net assimilation rate have been reported by George (1965). In other crops also, varietal differences in leaf area index and net assimilation rate have been reported (Watson, 1947). It appears that in this crop, limited attempts have been made to study all the growth characteristics. This paper describes the differences in most of the growth characteristics in six sugar-cane varieties.


1992 ◽  
Vol 19 (2) ◽  
pp. 109 ◽  
Author(s):  
J Masle

Genotypes of wheat and barley, including modern and landrace lines, were compared in their response to soil resistance to root penetration during the early vegetative phase (up to 5 leaf stage). All genotypes exhibited reduced growth and transpiration rates at high soil resistance, but there was large variation in the magnitude and time course of these effects and in the mechanisms underlying the growth reduction (changes in net assimilation rate, carbon partitioning within the plant, relative effects of leaf primordia development, versus growth of expanding leaves). Similar wide ranges of responses were observed among landrace and modern wheats. In both wheat and barley, the genotypes with lower sensitivity to soil resistance, in terms of relative growth rate, were those with the slowest net assimilation rate and root growth rate at low soil resistance, and those for which carbon allocation to the impeded roots, relative to the shoot, was significantly increased, to the extent that root relative growth rate even became greater (in terms of mass, not of length) than on loose soil. For a number of genotypes, growth was slowed down throughout the experiment whereas for others it was reduced only during the first few days following germination. In contrast, transpiration rate was at all stages lower at high than at low soil resistance. This indicates that the effects of soil resistance to root penetration on stomatal conductance involve different controls - or different sensitivities to a common signal - from those operating on cell division and expansion.


Author(s):  
Ranjeet Kour ◽  
B. C. Sharma ◽  
Anil Kumar ◽  
Paramjeet Kour ◽  
Brij Nandan

The field experiments were carried out during rabi season of 2009-10 and 2010-11 at the Research Farm of Sher-e-Kashmir University of Agricultural Sciences and Technology of Jammu, Chatha to assess the physiological growth indices in chickpea+mustard intercropping system under different weed management practices. The significant superiority of replacement series treatment for leaf area index of chickpea over additive series treatment was noticed. The crop of sole chickpea was followed by replacement and additive series treatments in recording highest dry matter, crop growth rate and net assimilation rate values. Sole stand of chickpea recorded numerically higher relative growth rate (RGR) followed by replacement and additive series treatments. Weed free treatment recorded numerically the highest crop growth rate (CGR) and net assimilation rate (NAR) of chickpea at all the stages of observation. Sole chickpea produced higher yield as compared to chickpea+mustard when grown in additive and replacement series in the respective order.


Author(s):  
A. Reshma ◽  
P. Latha ◽  
V. Umamahesh ◽  
R. P. Vasanthi ◽  
P. Sudhakar

Groundnut is grown during July to October in kharif season, however area under early kharif (sowing in May) is increasing in Andhra Pradsh, where ever irrigation facilities exists. Hence to identify suitable variety for the situation, fourteen pre release and two released groundnut genotypes were evaluated during early kharif 2013 for growth, physiological traits and yield attributes. At harvest genotypes TCGS-1375 (41.331 g plant-1), TCGS-1342(41.059 g plant-1) significantly recorded higher total dry matter compared to all other cultivars and checks followed by TCGS-1330 (36.667 g plant-1), TCGS-1349 (36.433 g plant-1). TCGS-1342 recorded significantly higher Crop Growth Rate (CGR) value of 33.848 g m-2 day-1, where as TCGS-1346 (0.1265 g dm-2 day-1) and TCGS-1330 (0.1262 g dm-2 day-1) recorded significantly higher Net Assimilation Rate (NAR) values at 45-60 DAS. Cultivar, TCGS-1330 recorded significantly higher pod yield 4210.44 Kg ha-1 compared to other entries and checks. The results revealed that pre release genotypes, TCGS-1342, TCGS-1375, TCGS-1330, TCGS-1346 recorded high physiological efficiency in terms of growth and physiological traits viz. total dry matter (TDM), crop growth rate (CGR), net assimilation rate (NAR) and leaf area index (LAI) and also recorded high pod yield.


2020 ◽  
Vol 41 (6supl2) ◽  
pp. 2911-2922
Author(s):  
Miria Rosa Durigon ◽  
◽  
Joanei Cechin ◽  
Franciele Mariani ◽  
Gerarda Beatriz da Silva Pinto ◽  
...  

Plant growth analysis is useful for determining adequate management practices and exploring the maximum yield potential of cultivars or hybrids. Canola hybrids with resistance to herbicides have been studied and registered for Brazilian conditions, as they improve weed management in canola crops. This study evaluated the growth of canola hybrids resistant to triazine or imidazolinone herbicides compared to a sensitive hybrid. The experiment was conducted using a completely randomized design, with four replications, in a bifactorial scheme using three hybrids and six sampling times. The canola hybrids used were Hyola 571CL (resistant to imidazolinones), Hyola 555TT (resistant to triazines), and Hyola 61 (sensitive to both herbicides). Height, leaf area, and dry matter of roots, leaves, stems, and shoots of the plants were evaluated at 14, 28, 42, 56, 70, and 119 days after emergence (DAE). The physiological indices absolute growth rate, leaf area ratio, specific leaf area, and net assimilation rate were calculated, and yield indices evaluated. Compared to Hyola 61, the Hyola 555TT hybrid showed lower values of leaf dry matter at 70 DAE, absolute growth rate up to 56 DAE, and net assimilation rate at 14 and 28 DAE, and a higher leaf area ratio at 56 DAE, whereas the hybrid Hyola 571CL presented lower leaf area and lower leaf dry matter at 70 DAE. At flowering, compared to Hyola 61, the hybrid Hyola 571CL presents lower leaf area, and the hybrids Hyola 555TT and Hyola 571CL have lower leaf dry matter accumulation. Differences in the growth of canola hybrids Hyola 555TT, Hyola 571CL and Hyola 61 do not cause differences in their grain yield.


Author(s):  
Ranjeet Kour ◽  
B. C. Sharma

A field experiment was carried out during rabi seasons of 2009-10 and 2010-11 at the Research Farm of Sher-e-Kashmir University of Agricultural Sciences and Technology at Chatha, Jammu to assess the physiological growth indices in chickpea+mustard intercropping system under different weed management practices. The significant superiority of replacement series treatment for leaf area index of mustard over additive series treatment was noticed. The sole crop of mustard was followed by replacement and additive series treatments in recording highest dry matter, crop growth rate and net assimilation rate values. Sole stand of mustard recorded numerically higher relative growth rate (RGR) followed by replacement and additive series treatments. Weed free treatment recorded numerically highest crop growth rate (CGR) and net assimilation rate (NAR) of mustard at all the stages of observation. As regards yield, sole stand recorded significantly higher values of grain and was followed by additive and replacement series which in turn were differed significantly from one another in chickpea+mustard intercropping system.


1977 ◽  
Vol 57 (3) ◽  
pp. 797-801 ◽  
Author(s):  
W. B. COLLINS

The basis of differences in tuber and plant development in potato, due to differences in canopy size, was studied by measuring changes in plant dry weight and leaf area throughout the growing season. Differing canopy sizes were obtained by selecting three cultivars from the Canada Potato Breeding Program. These were F57048, Grand Falls, and F62008, which normally produce small, medium and large sized canopies respectively, with similar tuber yields. Differences in total and tuber dry weight through the season were slight compared to differences observed in leaf and stem growth. The branching capacity of the cultivars appeared to be the major determinant of canopy size. In these three cultivars, as canopy size increased, the initial tuber growth rate immediately following tuberization decreased. Thus, in the two smaller cultivars, the early tuber growth rate was more critical in determining final yield than was the case in the large-canopied cultivar, F62008. As expected, the net assimilation rate increased as canopy size decreased. The evidence indicated that the demands of the developing tubers exerted the greatest influence on the net assimilation rate.


2009 ◽  
Vol 66 (6) ◽  
pp. 733-741 ◽  
Author(s):  
Alessandra Aparecida Giacomini ◽  
Sila Carneiro da Silva ◽  
Daniel Oliveira de Lucena Sarmento ◽  
Cauê Varesqui Zeferino ◽  
Salim Jacaúna Souza Júnior ◽  
...  

Grazing strategies alter sward leaf area patterns of growth, affecting herbage accumulation and utilisation. The objective of this experiment was to evaluate the growth of marandu palisadegrass (Brachiaria brizantha cv. Marandu) swards subjected to strategies of intermittent stocking. The experiment was carried out in Piracicaba, São Paulo, Brazil, from October/2004 to September/2005. Swards were grazed at 95 and 100% canopy light interception (LI) to post-grazing heights of 10 and 15 cm, following a 2 × 2 factorial arrangement with four replications in a randomised complete block design. The response variables evaluated were: crop growth rate, relative growth rate, net assimilation rate, leaf area ratio and leaf weight ratio. In early and late spring, the highest crop growth rate was recorded for treatment 95/15 (11.2 and 10.1 g m-2 day-1, respectively), along with high values of net assimilation rate (4.4 and 6.9 g m-2 day-1, respectively), leaf area ratio (0.0095 and 0.0103 m-2 g-1, respectively) and leaf weight ratio (0.56 and 0.56 g g-1, respectively). To compensate reductions in net assimilation rate plants made some morphological and physiological adjustments increasing leaf area and leaf weight ratio. Relative growth rate and net assimilation rate were 26 and 50% higher, respectively, on swards grazed at 95% than at 100% LI. In early spring treatments 100/10 and 95/15 resulted in the highest relative growth rate (0.086 and 0.059 g m-2 day-1, respectively). Treatment 95/15 resulted in the most favourable pattern of growth (crop growth rate, relative growth rate, net assimilation rate), particularly during the transition period between winter and spring.


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