Phosphorus Deficiency Impairs Shoot Regrowth of Sugarcane Varieties

Abstract

SUMMARYThe shoot regrowth vigour of sugarcane varieties having contrasting phosphorus (P) efficiency was evaluated under varying soil P availability. The P-inefficient (IAC91-1099 and IACSP94-2101) and -efficient (IACSP94-2094 and IACSP95-5000) sugarcane varieties were grown under low (25 mg P kg −1 soil) or high (400 mg P kg −1 soil) P supply at planting. After 90 days (first cycle of growth), the shoots were harvested and regrowth was studied 70-75 days later by evaluating photosynthesis, leaf area formation, biomass production and P uptake. The shoot dry matter (DM) of sugarcane regrowth subjected to a low P supply was genotype-dependent, with the P-efficient varieties exhibiting greater values than the inefficient ones. This result was explained by the greater efficiency of IACSP94-2094 and IACSP95-5000 in acquiring P rather than P utilization efficiency for shoot biomass production. The root P stored during the first cycle of growth would represent only a minor fraction (< 20%) of the total P content in the shoots at the end of the regrowth period. Thus, we argue that the improved shoot P uptake of the P-efficient varieties was related to their ability to sustain P acquisition after harvesting rather than to the remobilization of root P reserves. Moreover, our data revealed that net CO 2 assimilation per leaf area was not associated with differential performance among varieties under P deficiency, suggesting a more critical role of total leaf area in photosynthate supply for sugarcane regrowth. In conclusion, sugarcane regrowth is improved in P-efficient varieties under P deficiency conditions, a finding of practical relevance as such ability might benefit the productivity and the longevity of sugarcane ratoons in low P tropical soils.

Sequential Management of Commercial Rosewood (Aniba rosaeodora Ducke) Plantations in Central Amazonia: Seeking Sustainable Models for Essential Oil Production

“…Similar results were reported by Zambrosi et al [61] from studies on the influence of P levels on plantation sugarcane shoots. Correlations between regrowth and TSS ratios confirm a need by rosewood plants for this reserve to meet respiratory demands and for regrowth after losing photosynthetic capacity.…”

“…This was also found in rosewood regrowth, most evidently for P and K. Some studies indicate that, for species that do not store reserves in underground tissues (as tuber-producing species do), the highest concentrations of nutrients in sprouting tissues occur mostly due to an ability to acquire, directly from soil, those elements necessary to meet the physiological requirements of sprouting [61].…”

“…P is a component of sugar phosphates, nucleic acids, nucleotides, and coenzymes, and plays a central role in reactions involving ATP, which occurs in higher concentrations in juvenile tissues [61]. An understanding of how this nutrient is used in rosewood shoots is key since low P levels are considered the main limiting factor for the development of agriculture in the Amazon [66].…”

“…An understanding of how this nutrient is used in rosewood shoots is key since low P levels are considered the main limiting factor for the development of agriculture in the Amazon [66]. Deficiency of this element results in undersized plants, with appearant necrosis on the leaves, fruit and stems, and leaves that are twisted and colored reddish-purple, a trait associated with anthocyanin accumulation [61,67].…”

Technological Parameters of Sugarcane Varieties Attacked by Diatraea Saccharalis.

“…Elevation in fiber content is acceptable till the limit between 10,5 to 12,5% (Rodolfo Junior et al, 2016), since a greater value turns into a limitation factor in the milling process (Souza et al 2005). Alongside the borer´s attack, biotic stresses and biotic can influence the technological parameters of sugarcane (Showler, 2016); such as chemical soil attributes (Zambrosi et al, 2017) and even the choice of the harvest method.…”