摘要
Phosphorus(P)deficiency is a major constraint in rice production,causing significant reductions in growth and yield.While P deficiency typically decreases chlorophyll content in many plant species,our previous studies revealed an unexpected increase in chlorophyll content in P-deficient rice seedlings.Here,we investigated this phenomenon in KDML105 rice under various P regimes and analyzed the physiological mechanisms involved.We found that P-deficient rice seedlings significantly increased chlorophyll a,chlorophyll b,and carotenoid contents in young leaves while reducing photosystem II quantum yield and enhancing non-photochemical quenching.This response was specific to P deficiency and was not observed under other stress conditions such as salinity or copper toxicity,which induced oxidative stress.Time-course experiments revealed that increased chlorophyll accumulation was an early adaptive response that occurred primarily in young leaves,while older leaves eventually developed chlorosis under prolonged P deficiency.The increased chlorophyll content may be attributed to reduced leaf width and altered leaf morphology under P-limited conditions.Furthermore,using custom hyperspectral imaging analysis coupled with machine learning classification,we successfully differentiated P status in rice leaves with 98.96%accuracy in older leaves.This study demonstrates that enhanced chlorophyll accumulation is a characteristic early response to P deficiency in rice,rather than a typical general stress response observed in other conditions.Our findings highlight the limitations of relying solely on chlorophyll-based indices as indicators of plant health in precision agriculture,especially regarding phosphorus(P)nutrition management.This underscores the need for a more comprehensive approach and lays the groundwork for developing advanced remote sensing technologies aimed at accurately assessing P status in rice cultivation.
基金
supported by the Prince of Songkla University,Thailand(Grant No.SCI6602020S)。
