Lower LMR Research Articles

Significance of laboratory biomarkers in monitoring patients with COVID-19 pneumonia

Clinical and laboratory parameters are useful tools to improve success rates in the management of COVID-19 patients. Indices such as NLR, PLR, MHR, SII, AIP and CAR may indicate poor prognosis in predicting poor prognosis in COVID-19. It was aimed to identify such parameters of disease progression in COVID-19 patients by examining demographic data, comorbid conditions, some biochemical and hematological parameters. A retrospective analysis was performed for patients admitted to intensive care unit or pulmonary diseases department or treated on an outpatient basis due to a diagnosis of COVID-19. Patients with positive PCR test and thoracic CT compatible with COVID-19 pneumonia were included in the study. A control group was formed from volunteers of similar age and gender. The study population was divided into four groups as follows: patients admitted to intensive care unit (ICU group); patients admitted to chest diseases department (Inpatient Group); patients treated on an outpatient basis (Outpatient Group); and controls (Control Group). There were 61, 201, and 30 patients in the ICU, inpatient, and outpatient groups, respectively. A total of 96 subjects served as controls. Study groups were comparable with respect to gender distribution. ICU patients had higher NLR, PLR, AIP, SII, and CAR, and lower LMR as compared to other groups. NLR, SII, AIP, and CAR emerged as predictors of ICU admission, while MHR was predictive of inpatient treatment. Certain clinical and laboratory parameters may be useful tools for improving the success of COVID-19 management. High NLR, SII, AIP, CAR, and MHR values may indicate low prognosis in COVID-19 patients.

The role of preoperative inflammatory markers in patients with central nervous system tumors, focus on glioma.

CNS tumors, particularly gliomas, are associated with a high rate of disability and lethality, and are typically diagnosed with histopathology and immunohistochemistry. Our research aims to develop a minimally invasive method for diagnosing, grading and molecular typing glioma. We collected patients who underwent surgery for glioma, Trigeminal neuralgia/Hemifacial spasm, schwannoma, pituitary adenomas and meningioma at our hospital from June 2019 to June 2021. Preoperative WBCs, neutrophils, lymphocytes, monocytes, platelet counts and albumin levels were collected. Preoperative NLR, dNLR, PLR, LMR and PNI were calculated, and the correlation between them and glioma diagnosis as well as grading was analyzed. We also evaluated the diagnostic significance of NLR, dNLR, PLR, LMR, PNI and their combinations for gliomas, particularly GBM, as well as the diagnostic significance of IDH molecular typing of gliomas. There were 182 healthy samples and 3101 diseased samples in our study. Compared with other groups, glioma patients had significantly higher preoperative NLR, dNLR and PLR values, but lower LMR and PNI values. Further analysis showed that NLR, dNLR, and PLR were positively correlated with glioma grading, while LMR and PNI were negatively correlated with glioma grading. For the diagnosis of glioma, NLR showed a maximum AUC value of 0.8099 (0.7823-0.8374). For GBM, NLR showed a maximum AUC value of 0.9585 (0.9467-0.9703). In the combination, NLR+dNLR showed the highest AUC value of 0.8070(0.7849-0.8291). NLR showed significant statistical significance in all grades of glioma IDH molecular typing, while PLR did not show statistical significance. NLR has the greatest value for the diagnosis, differential diagnosis, grading and molecular typing of gliomas. The NLR+dNLR combination also showed high sensitivity and specificity. We believe that inflammatory parameters may serve as economical and specific markers for glioma diagnosis, grading, molecular typing, and progression.

Prognostic Significance of PNI in Patients With Pancreatic Head Cancer Undergoing Laparoscopic Pancreaticoduodenectomy.

BackgroundRecently, several prognosis indicators based on inflammatory and nutritional factors, such as the neutrophil-to-lymphocyte ratio (NLR), plated-to-lymphocyte (PLR), lymphocyte-to-monocyte (LMR) and prognosis nutritional index (PNI), have been proposed as prognosis factors for several cancers. However, few studies have looked into PNI. The goal of this research was to see if preoperative PNI had any predictive value in patients with pancreatic head cancer who were having a laparoscopic pancreaticoduodenectomy.MethodsFrom February 11, 2018 to May 31, 2019, two hundred and fifty-one pancreatic head carcinoma patients were retrospectively enrolled. The receiver operator characteristic (ROC) curve was used to determine the cut-off value. Patients were divided into two groups: PNI > 45.1 (high PNI group) and PNI < 45.1 (low PNI group), and clinic-pathological data was compared between the two groups. The link between PNI and NLR, PLR, and LMR, and their effect on overall survival. In addition, the factors of postoperative survival were analyzed univariate and multivariate.ResultsPNI, NLR, PLR and LMR cut-off values were 45.1, 3.7,287.2 and 3.6, respectively. Between the two groups of patients, the low PNI group exhibited considerably higher PLR and lower LMR. PNI had a negative correlation with PLR and NLR (r = −0.329, p < 0.001 and r = 0.170, p = 0.014), but a positive correlation with LMR (r = 0.476, p < 0.001). The high PNI group had a considerably greater survival rate than the low PNI group (median survival days, 217 vs. 468, log-rank = 45.92, p < 0.001). PNI < 45.1(HR: 0.357, 95 percent CI, 0.263–0.485, p < 0.001) and LMR <3.6(HR: 0.705, 95 percent CI, 0.528–0.942, p < 0.018) were revealed to be possible predictive variable in univariate analysis. Only PNI <45.1 was found to be an independent predictive factor in multivariate analysis (HR: 0.359, 95%CI,: 0.256–0.502, p < 0.001).ConclusionsOur findings shoe that PNI is linked to a variety of systemic inflammatory response and can be used to predict survival in individuals with pancreatic head cancer.

Using Inflammatory Blood Markers as Useful Prognostic Factors in Patients Undergoing Neo-Adjuvant Therapy for Stage II-III Breast Cancer

<h3>Purpose/Objective(s)</h3> The prognostic value of inflammatory blood markers (IBMs) in breast cancer patients have been an area of growing interest. Most of the studies took parameters from one defined point, usually the pretreatment ones. Current study aims to investigate the potential prognostic significance of IBMs among patients with stage II-III breast cancer receiving neo-adjuvant therapy (NAT). <h3>Materials/Methods</h3> Patients with stage II-III breast cancer who received NAT and postoperative radiotherapy (RT) at a single institute from Jan 2009 to Dec 2016 were retrospectively reviewed. The neutrophil, lymphocyte, platelet and monocyte count were collected at different stages of treatment, after NAT but before surgery, before and after RT, respectively. LMR and SII was calculated for each patient. The breast cancer specific survival (BCSS) and locoregional recurrence free survival (LRRFS) were defined from the date of the start of RT until last follow up. Univariate and multivariate Cox regression analysis was performed to identify independent predictors for BCSS and LRRFS. Model performance was evaluated by the concordance index (c-index). <h3>Results</h3> In total, 205 patients were enrolled. After a median follow-up of 65 months, 19 BCSS events were identified. The optimal cutoff value of SII and LMR after NAT but before surgery by receiver operating characteristic curve were 467.76 × 10⁹ (AUC = 0.63) and 1.57 (AUC = 0.65). The five-year BCSS of the group with lower LMR (LMR≤1.57) and higher LMR (LMR > 1.57) were 74.2% and 93.7%, respectively (P = 0.001). The 5-year risk of BCSS in patients with high SII value (SII > 467.76 × 10⁹) and low SII value (SII≤467.76 × 10⁹) were 81.5% vs 96.4%, respectively, <i>P</i> = 0.003. The multivariate analysis found that in addition to the traditional prognostic factors including hormone receptor, ypT, ypN stage and lymphovascular invasion, both post-NAT LMR (HR = 0.28, 95% CI = 0.10-0.81, <i>P</i> = 0.02) and SII (HR = 4.06, 95% CI = 1.37-12.00, <i>P</i> = 0.01) were independent predictors for BCSS. The C-index of the multivariate model of Neo-Bioscore for BCSS was 0.71(95% CI = 0.83-0.59), which was improved to 0.80((95% CI = 0.94-0.67) by adding LMR and SII. The prognosis of pre-RT and post-RT SII on LRRFS was analyzed in124 patients. The optimal cutoff value of SII before and after RT were 412.2 × 10⁹ (AUC = 0.71) and 571.48 × 10⁹ (AUC = 0.69) respectively. Patients with pre-RT SII > 412.2 × 10⁹ or post-RT SII > 571.48 × 10⁹ had a higher rate of locoregional failure (<i>P</i> = 0.02 and <i>P</i> = 0.01). After adjusting for cT, cN stage and age, post-RT SII remained predictive of locoregional failure (HR = 10.22, 95% CI = 1.25-83.45, <i>P</i> = 0.03). <h3>Conclusion</h3> IBMs after NAT was useful prognostic factor for stage II-III breast cancer patients. Adding LMR and SII to Neo-Bioscore can further stratify the prognosis of BCSS. High level of SII after RT had a negative impact on local-regional control, whether it reflects preclinical studies of post-RT inflammation-mediated tumor recurrence needs further study.

Lymphocyte-to-monocyte ratio is a predictor of clinically significant prostate cancer at prostate biopsy.

Inflammation plays critical roles at different stages of carcinogenesis and cancer progression. Several previous studies showed conflicting results for the predictive role of systemic inflammation markers in the detection of clinically significant prostate cancers (CSPCs). We aimed to determine the predictive roles of lymphocyte-to-monocyte (LMR) and eosinophil-to-lymphocyte ratios (ELR) in the detection of CSPC at standard 12-core transrectal ultrasound-guided prostate biopsy (12-core-TRUS-Bx) using our large-cohort database. Clinical and pathological data of a total of 1740 men, who underwent initial standard 12-core TRUS-Bx, were analyzed. LMR and ELR were calculated from the prebiopsy complete blood count. Definitions of CSPC, LMR, and ELR were "Gleason grade group ≥2," "the lymphocyte counts/the monocyte counts," and "the eosinophil counts/the lymphocyte counts," respectively. Median (interquartile range) of serum prostate-specific antigen(PSA) level and prostatic volume before TRUS-Bx were 7.59 (5.02-13.12) ng/ml and 38.2 (29.0-52.9) ml, respectively. Benign prostatic lesions, clinically insignificant prostate cancers (CIPCs), and CSPCs were detected in 1179 (67.8%), 180 (10.3%), and 381 (21.9%) patients, respectively. The patients with CSPCs had older age, a higher prevalence of diabetes mellitus or hypertension, a higher rate of digital rectal examination abnormality, higher serum PSA level, lower serum testosterone level, and lower LMR than those with benign lesions or CIPCs. However, there was no difference in ELR among the three (benign lesions, CIPCs and CSPCs). In all the patients, multivariate regression analysis showed that lower LMR was an independent predictor of CSPCs compared with ELR. In the subset of men with prostate volume ≥39.3 ml, lower LMR was an independent predictor of CSPCs compared with ELR. In the subset of men with prostate volume <39.3 ml, men with lower LMR showed the tendency of having a higher probability of CSPCs without any statistical significance on the contrary to ELR. Our data indicate that LMR can play an independent predictive role in the detection of CSPCs at initial 12-core-TRUS-Bx compared with ELR. The predictive role of the LMR appears to be significant for men with larger prostate volume rather than those with smaller prostate volume.

Peripheral blood inflammatory markers in predicting prognosis in patients with COVID-19. Some differences with influenza A.

BackgroundTo evaluate the ability of peripheral blood inflammatory markers in predicating the typing of COVID‐19, prognosis, and some differences between COVID‐19 and influenza A patients.MethodsClinical data on 285 cases laboratory‐confirmed as SARS‐CoV‐2 infection were obtained from a Wuhan local hospital's electronic medical records according to previously designed standardized data collection forms. Additional 446 Influenza A outpatients’ hematologic data were enrolled for comparison.ResultsNLR, SII, RLR, PLR, HsCRP, and IL‐6 were significant higher and LMR was lower in severe COVID‐19 patients than in mild COVID‐19 patients (p < .001). PLR and LMR were lower in the individuals with influenza A than those with COVID‐19 (p < .01). COVID‐19 patients with higher levels of NLR, SII, RLR, PLR, HsCRP, and IL‐6 and lower LMR were significantly associated with the severe type. AUC of NLR (0.76) was larger while the specificity of IL‐6 (86%) and sensitivity of HsCRP (89%) were higher than other inflammatory markers in predicating the typing of COVID‐19. PT had obvious correlation with all the inflammatory markers except RPR. NLR showed positive correlations with AST, TP, BUN, CREA, PT, and D‐dimer. Patients with high IL‐6 levels have a relatively worse prognosis (HR = 2.30).ConclusionPeripheral blood inflammatory markers reflected the intensity of inflammation and associated with severity of COVID‐19.NLR was more useful to predict severity as well as IL‐6 to predict prognosis of COVID‐19. PLR and LMR were initially found to be higher in SARS‐CoV‐2 virus‐infected group than in influenza A.

Can preoperative neutrophil to lymphocyte, lymphocyte to monocyte, or platelet to lymphocyte ratios differentiate glioblastoma from brain metastasis?

This retrospective analysis of patients aims to show the blood levels of preoperative inflammatory markers in patients with glioblastoma and brain metastasis and to provide the diagnostic accuracy of the neutrophil–lymphocyte (NLR), lymphocyte–monocyte (LMR), and platelet–lymphocyte (PLR) ratios between the 2 groups of patients.The retrospective reviews of the neutrophil, lymphocyte, monocyte, and platelet counts were analyzed in 80 patients with newly diagnosed glioblastoma and 70 patients with brain metastasis. The NLR, LMR, and PLR were calculated in each group. The differences in all the parameters were compared between the 2 groups.Although the neutrophil, monocyte, and platelet counts were higher and the lymphocyte count was lower in patients with metastasis, the difference was not significant. A significantly higher PLR (P = .004) and a lower LMR (P = .01) were found in patients with brain metastasis. Although both PLR and LMR had diagnostic accuracy in differentiating glioblastoma from brain metastasis, LMR showed the highest diagnostic accuracy. NLR showed no diagnostic accuracy.Systemic inflammation is more severe in glioblastoma than in brain metastasis, and LMR is more sensitive and/or specific than PLR in differentiating glioblastoma from brain metastasis. Therefore, LMR (less likely PLR) can be used as an index for differentiating between glioblastoma and brain metastasis before surgery.

The utility of peripheral blood leucocyte ratios as biomarkers in infectious diseases: A systematic review and meta-analysis

To assess the utility of the neutrophil:lymphocyte (NLR), lymphocyte:monocyte (LMR) and platelet:lymphocyte ratios (PLR) as infection biomarkers. PubMed/MEDLINE, Embase and Cochrane databases were searched to identify eligible articles. Studies of diagnosis, severity or outcome were included. PROSPERO systematic review registration CRD42017075032. Forty studies were included, reporting on bacterial and viral infections, malaria, and critical illness due to sepsis. Ten studies reported an association of higher NLR with bacteraemia, supported by meta-analysis of patient-level data (five studies, n = 3320; AUC 0.72, p<0.0001) identifying a cut-off of >12.65. Two studies reported an association with lower LMR and diagnosis of influenza virus infection in patients with respiratory tract infection. Meta-analysis of patient-level data (n = 85; AUC 0.66, p = 0.01) identified a cut-off of ≤2.06. The directionality of associations between NLR and outcomes in heterogeneous cohorts of critically ill adults with sepsis varied. Potential clinical utility was also demonstrated in pneumonia (NLR), pertussis (NLR), urinary tract infection (NLR), diabetic foot infections (NLR) and Crimean Congo Haemorrhagic Fever (PLR). Longitudinal measurement of LMR during respiratory virus infection reflected symptoms and NLR during sepsis and bacteraemia predicted mortality. Peripheral blood leucocyte ratios are useful infection biomarkers, with the most evidence related to diagnosis of bacteraemia and influenza virus infection. In critical illness due to sepsis, a signal towards an association with NLR and outcomes exists, and NLR should be evaluated in future stratification models. Longitudinal measurement of ratios during infection could be informative. Overall, these biomarkers warrant further recognition and study in infectious diseases.

The early prognostic value of inflammatory markers in patients with acute pancreatitis

The aim of this study was to compare the prognostic value of inflammation-based prognostic markers with the more mature scoring system BISAP in patients with AP and identify the best predictors. We retrospectively analysed the data of patients with AP who were treated in our hospital from January 2017 to March 2018 and compared the prognostic value of these inflammation-based prognostic markers with the BISAP score in patients with AP. Higher BISAP score, NLR, PLR, ACC, and BUN gradually increased (all P < 0.05), and lower LMR and TC (P < 0.001) were associated with severity of AP. Compared with the patients without persistent organ failure, the patients with POF were older (P = 0.049) and had a higher BISAP score (P < 0.001), NLR (P = 0.003), PLR (P < 0.001) and ACC (P = 0.047), BUN (P = 0.011), and creatinine (P = 0.023), RDW (P = 0.021), but lower LMR (P = 0.003) and TC (P < 0.001) at baseline. The BISAP score (OR = 2.117, 95% CI 1.487 to 3.016, P < 0.001), NLR (OR = 1.053, 95% CI: 1.009 to 1.101, P = 0.019) and TC (OR = 0.088, 95% CI: 0.024 to 1.030, P < 0.001) were independent factors for predicting SAP. For predicting the occurrence of POF, TC and PLR had an area under the ROC curve (TC AUC = 0.784, P < 0.001, with a 2.18 cut-off value, PLR AUC = 0.731, P < 0.001, with a 173.13 cut-off value) that was not inferior to the BISAP score (AUC = 0.708), and PLR had the best sensitivity (95.8%), BUN had the best specificity (44.71%), respectively. There is no difference in their predictive value for POF. NLR and TC are the most powerful markers in this patient series, they have a prognostic value which is not weaker than BISAP, and are equally simple, rapid.

Searching for new serum marker: Neutrophil-to-lymphocyte ratio (NLR) as a predictor of severity and the presence of necrosis in acute pancreatitis

The aim of this study was to compare the prognostic value of inflammation-based prognostic markers with the more mature scoring system BISAP in patients with AP and identify the best predictors.We retrospectively analysed the data of patients with AP who were treated in our hospital from January 2017 to March 2018 and compared the prognostic value of these inflammation-based prognostic markers with the BISAP score in patients with AP.Higher BISAP score, NLR, PLR, ACC, and BUN gradually increased (all P < 0.05), and lower LMR and TC (P < 0.001) were associated with severity of AP. Compared with the patients without persistent organ failure, the patients with POF were older (P = 0.049) and had a higher BISAP score (P < 0.001), NLR (P = 0.003), PLR (P < 0.001) and ACC (P = 0.047), BUN (P = 0.011), and creatinine (P = 0.023), RDW (P = 0.021), but lower LMR (P = 0.003) and TC (P < 0.001) at baseline. The BISAP score (OR = 2.117, 95% CI 1.487 to 3.016, P < 0.001), NLR (OR = 1.053, 95% CI: 1.009 to 1.101, P = 0.019) and TC (OR = 0.088, 95% CI: 0.024 to 1.030, P < 0.001) were independent factors for predicting SAP. For predicting the occurrence of POF, TC and PLR had an area under the ROC curve (TC AUC = 0.784, P < 0.001, with a 2.18 cut-off value, PLR AUC = 0.731, P < 0.001, with a 173.13 cut-off value) that was not inferior to the BISAP score (AUC = 0.708), and PLR had the best sensitivity (95.8%), BUN had the best specificity (44.71%), respectively. There is no difference in their predictive value for POF.NLR and TC are the most powerful markers in this patient series, they have a prognostic value which is not weaker than BISAP, and are equally simple, rapid.

Prognostic effects of preoperative obstructive pneumonitis or atelectasis and comparison with tumor size in non-small cell lung cancer.

In the eighth TNM staging system proposal, lung cancer with part or complete obstructive pneumonitis/atelectasis was classified to T2 category, and dividing lines of T category were changed. We conducted this study to search prognostic effect of preoperative obstructive pneumonitis/atelectasis and its comparison with tumor size. We collected clinical characteristics, preoperative hematological indicators, follow-up information of 1,313 lung cancer patients. Chi-square test was used to search relationship between obstruction pneumonitis/atelectasis and other factors. Kaplan-Meier (K-M) curves and cox regression methods were used for survival analysis. Preoperative obstructive pneumonitis/atelectasis indicated shorter OS (HR: 1.308; 95% CI: 1.058-1.619) and RFS (HR: 1.276; 95% CI: 1.032-1.579) as an independent factor. In comparison with tumor size, we found patients with obstructive pneumonitis/atelectasis and T1 size tumor had similar prognosis to those with T2 size but without obstructive pneumonitis/atelectasis, and OS, RFS of patients with obstructive pneumonitis/atelectasis and T2 size were significantly shorter than those with T2 tumor size but without obstructive pneumonitis/atelectasis, while similar to patients with T3 tumor size but without obstructive pneumonitis/atelectasis according to division by the eighth edition. We also found obstructive pneumonitis/atelectasis was significantly related to higher neutrophil (P<0.001), platelet (P<0.001), monocyte (P<0.001), NLR (P<0.001), PLR (P=0.002), ESR (P<0.001) and lower LMR (P<0.001). Preoperative obstructive pneumonitis/atelectasis predicted poor survival independently in non-small cell lung cancer (NSCLC). And we suggested which T staging group the patients with obstructive pneumonitis/atelectasis would be divided to should depend on tumor size in the eighth TNM staging system.

Signatures of reproductive events on blood counts and biomarkers of inflammation: Implications for chronic disease risk.

Whether inflammation mediates how reproductive events affect chronic-disease risk is unclear. We studied inflammatory biomarkers in the context of reproductive events using National Health and Nutrition Examination Survey (NHANES) data. From 15,986 eligible women from the 1999–2011 data cycles, we accessed information on reproductive events, blood counts, C-reactive protein (CRP), and total homocysteine (tHCY). We calculated blood-count ratios including: platelet-lymphocyte (PLR), lymphocyte-monocyte (LMR), platelet-monocyte (PMR), and neutrophil-monocyte (NMR). Using sampling weights per NHANES guidelines, means for counts, ratios, or biomarkers by reproductive events were compared using linear regression. We performed trend tests and calculated p-values with partial sum of squares F-tests. Higher PLR and lower LMR were associated with nulliparity. In postmenopausal women, lower PMR was associated with early age at first birth and higher NMR with later age at and shorter interval since last birth. Lower PNR and higher neutrophils and tHCY were associated with early natural menopause. In all women, the neutrophil count correlated positively with CRP; but, in premenopausal women, correlated inversely with tHCY. Reproductive events leave residual signatures on blood counts and inflammatory biomarkers that could underlie their links to chronic disease risk.

Peripheral blood lymphocyte/monocyte ratio following completion of first-line therapy predicts early relapse in patients with diffuse large B cell lymphoma.

To investigate whether the post-therapy lymphocyte/monocyte ratio (ALC/AMC ratio or LMR) predicts early relapse in patients with diffuse large B cell lymphoma (DLBCL), we enrolled 125 consecutive patients with DLBCL and followed up from 2005 to 2015 in our hospital. The LMR was measured following completion of first-line therapy. We found that the LMR following completion therapy was a strong predictor of early relapse, which is less than 12months after diagnosis. A low LMR was significantly associated with early relapse in both univariate [odds ratio (OR) = 8.8; P = 0.006] and multivariate analysis (OR = 8.951; P = 0.011). The low-LMR group (<2.9) had poorer outcomes than the high-LMR group (≥2.9), with a lower 2-year progression-free survival rate (78.9 versus 97.1%, P = 0.002) and 2-year OS rate (82.5 versus 98.5%, P = 0.002). This study suggests that a lower LMR following completion of first-line therapy can be used as a marker to predict early relapse in patients with DLBCL.

Biomass allocation and leaf chemical defence in defoliated seedlings of Quercus serrata with respect to carbon-nitrogen balance.

Both nutrient availability and defoliation affect the carbon-nutrient balance in plants, which in turn influences biomass allocation (e.g. shoot-to-root ratio) and leaf chemical composition (concentration of nitrogen and secondary compounds). In this study it is questioned whether defoliation alters biomass allocation and chemical defence in a similar fashion to the response to nutrient deficiency. Current-year seedlings of Quercus serrata were grown with or without removal of all leaves at three levels of nutrient availability. Plant nitrogen concentration (PNC), a measure of the carbon-nutrient balance in the plant, significantly decreased immediately after defoliation because leaves had higher nitrogen concentrations than stems and roots. However, PNC recovered to levels similar to or higher than that of control plants in 3 or 6 weeks after the defoliation. Nitrogen concentration of leaves produced after defoliation was significantly higher than leaf nitrogen concentration of control leaves. Leaf mass per plant mass (leaf mass ratio, LMR) was positively correlated with PNC but the relationship was significantly different between defoliated and control plants. When compared at the same PNC, defoliated plants had a lower LMR. However, the ratio of the leaf to root tissues that were newly produced after defoliation as a function of PNC did not differ between defoliated and control plants. Defoliated plants had a significantly lower concentration of total phenolics and condensed tannins. Across defoliated and control plants, the leaf tannin concentration was negatively correlated with the leaf nitrogen concentration, suggesting that the amount of carbon-based defensive compounds was controlled by the carbon-nutrient balance at the leaf level. Defoliation alters biomass allocation and chemical defence through the carbon-nutrient balance at the plant and at the leaf level, respectively.

Photosynthetic Acclimation to Elevated CO 2 in Relation to Biomass Allocation in Cotton

Biomass allocation to leaf tissues and photosynthetic acclimation to CO2 by cotton were investigated in two experiments. Plants were grown at ambient and elevated CO2 concentrations with growth restricting phosphorus supplies in both experiments and in root restricting pot volumes in the first experiment. In both experiments, elevated CO2 concentrations decreased the maximum carboxylation rate (V-cmax) and the CO2 saturated rate of photosynthesis indicative of photosynthetic acclimation to elevated CO2 concentrations. In the first experiment, the percentage reduction in V-cmax under elevated CO2 concentration was least at a P supply of 2.1 mg P plant(-1), greatest at 6.1 mg P plant(-1), but then decreased at 18.2 mg P plant(-1). The greater acclimation at the middle P supply was associated with a higher ratio of leaf mass to plant mass (LMR) than in other treatments and the lesser acclimation at the highest P treatment coincided with a lower LMR. In the second experiment the reduction in V-cmax at elevated CO2 was less than in the first experiment but was also associated with a greater allocation of dry matter to leaf tissues during growth. In both experiments, V-cmax was not correlated to the relative degree of biomass enhancement at elevated CO2 nor with the degree of root growth restriction in small pots. These data support the hypothesis that acclimation of photosynthesis to elevated CO2 concentrations is mediated by shifts in allocation between leaves and the rest of the plant, induced by environmental conditions during growth, such that carbohydrate supply remains in balance with the utilization capacity of sink tissues.