Differential physiological behavior of sugarcane genotypes in response to sparingly soluble phosphorus‐sources. Issue 2 (6th January 2021) - Zhou, Wenling
Abstract: Aims : This study was initiated to evaluate different responses of sugarcane ( Saccharum officinarum L.) genotypes to sparingly soluble phosphorus (P) treatments and to identify useful plant traits contributing to P efficiency for the selection of efficient and responsive genotypes. Methods : Plant growth, root morphological parameters, photosynthetic parameters, and P efficiency were evaluated under soluble P [KH2 PO4 (K‐P)] and sparingly soluble P [Ca3 (PO4)2 (Ca‐P), AlPO4 (Al‐P), FePO4 · 4 H2 O (Fe‐P), and sodium phytate C6 H6 O24 P6 Na12 (Org‐P)] treatments using sand cultures. Results : Sugarcane growth was inhibited under sparingly soluble P or low P treatments, by an average of 22.9% or 71.3% reduction in shoot and root biomass, respectively. Al‐P and Org‐P had higher bioavailability than Fe‐P and Ca‐P for the tested sugarcane genotypes, which showed lower rate decreases for biomass, root morphological and photosynthetic parameters under Al‐P and Org‐P treatment than those under Fe‐P and Ca‐P. In addition, the P content in shoot decreased by an average of 29.2% and 39.2% under Al‐P and Org‐P treatment, respectively, while 55.7% and 62.9% reduction was detected under Fe‐P and Ca‐P treatment, respectively, compared with K‐P treatment. BC2‐32 (hybrid progeny of sugarcane and E. arundinaceus ) exhibiting greater P absorption efficiency than other two genotypes under P‐starvation treatments; and the root length, root surface areas, root volume, P accumulation, net photosynthetic rate, and shoot and root dry matter of BC2‐32 were greater than those of other genotypes under sparingly soluble P forms. Significantly correlations were found between root morphological parameters, photosynthetic parameters and P efficiency under sparingly soluble P and low‐P treatment, indicating that stronger root system and less sensitivity of photosynthesis may contribute greatly to activate and take up more P from sparingly soluble P sources. Conclusions : Therefore, BC2‐32 would be the ideal material for breeding good varieties and exhibited better growth behavior to P‐deficient soils, and root morphological parameters and photosynthetic rate would be the useful plant traits in combination to screen these sugarcane varieties.