Phosphorus and Zinc Interaction Influence Leaf Area Index in Fine vs. Coarse Rice (Oryza sativa L) Genotypes in Northwest Pakistan

Abstract

Leaf area index (LAI) is a measure of leafiness per unit ground area and denotes the extent of photosynthetic machinery is an important growth and yield-determining factor because it is a major determinant of light interception and transpiration. Phosphorus (P) and zinc (Zn) are the most important factors affecting LAI of rice (Oryza sativa L.). A field experiment was conducted to assess the impact of phosphorus (0, 40, 80, 120 kg P/ ha) and zinc levels (0, 5, 10, 15 kg Zn/ha) on LAI of rice (O. sativa L.) genotypes (fine and coarse [Fakhr-e-Malakand and Pukhraj]). The experiment was conducted on farmer field at Batkhela, Malakadnd in Northwest Pakistan during summer 2011 and 2012. When combined over the 2 years, the data revealed that the highest LAI at three different growth stages (tillering, heading, and physiological maturity [PM]) was obtained with application of the highest P level (120 kg/ha) being at par with 80 kg P/ha, while the lowest LAI was recorded when P was not applied. Similarly, the highest LAI was obtained with application of the two higher Zn levels (10 and 15 kg Zn/ha), while the lowest LAI was recorded when Zn was not applied. In the case of rice genotypes, the highest LAI was obtained from Pukhraj than other two genotypes at all growth stages. The other two rice genotypes (Fakher-e-Malakand and Basmati-385) produced statistically similar LAI at different growth stages. The higher LAI of Pukhraj was attributed to its long and wider leaves that resulted in higher mean single leaf area, leaf area per tiller, per hill, and per square meter. The LAI was the highest at heading stage than at early (tillering) and later (PM) growth stages. The increase in LAI was attributed to the increase in tillers number and leaf area/hill. The increase in LAI showed a positive impact on crop growth rate, dry matter, and yield. Application of 120 kg P+10 kg Zn/ha to rice genotype Pukhraj was more beneficial in terms of higher LAI and productivity in the study area.

N and K interactions in cucumber plants artificially inoculated with P. cubensis

“…In general, leaf area growth is mainly influenced by nutrients and modified by N addition [20] however determination of leaf size is complicated and runs counter to prediction [21]. The results of the present study confirm that N and K combined at high levels was more beneficial in terms of leaf size, probably due to their implication in plant growth, as shown for other nutrient combination [22].…”

Phosphorus Uptake Model of Oil Palm Seedlings in the Main Nursery

“…Increasing P fertilization at P1, P2 and P3 increased the LAI of oil palm seedlings to optimum levels. Amanullah et al [16] reported that P and zinc (Zn) were the most important factors influencing rice LAI. P deficiency affects the relative rates of leaf area expansion and plant growth during the early stages.…”