Dryobalanops aromatica Gaertn. f. is a major tropical canopy species in lowland tropical rain forests in Peninsular Malaysia. Diurnal changes in net photosynthetic rate (A) and stomatal conductance to water vapor (g(s)) were measured in fully expanded young and old leaves in the uppermost canopy (35 m above ground). Maximum A was 12 and 10 micro mol m(-2) s(-1) in young and old leaves, respectively; however, because of large variation in A among leaves, mean maximum A in young and old leaves was only 6.6 and 5.5 micro mol m(-2) s(-1), respectively. Both g(s) and A declined in young leaves when T(leaf) exceeded 34 degrees C and leaf-to-air vapor pressure deficit (DeltaW) exceeded 0.025, whereas in old leaves, g(s) and A did not start to decline until T(leaf) and DeltaW exceeded 36 degrees C and 0.035, respectively. Under saturating light conditions, A was linearly related to g(s). The coefficient of variation (CV) for the difference between the CO(2) concentrations of ambient air and the leaf intercellular air space (C(a) - C(i)) was smaller than the CV for A or g(s), suggesting that maximum g(s) was mainly controlled by mesophyll assimilation (A/C(i)). Minimum C(i)/C(a) ratios were relatively high (0.72-0.73), indicating a small drought-induced stomatal limitation to A and non-conservative water use in the uppermost canopy leaves.
Relapsing polychondritis (RP) is a rare multisystem condition. Nearly 50% of patients are suffering from airway involvement in RP and it can be fatal. Besides immunotherapies, endobronchial stenting has been found to be useful in the treatment. Insertion of endobronchial stents in patients with RP has it's own complications and has been associated with increasing morbidity and mortality. We describe placement of multiple endobronchial stents to prevent airway closure in a 76-year-old man with RP due to recurrent dyspnea. Insertion of multiple stents (6th stent) in the left main bronchus was necessary due to severe narrowing of the left main bronchus. Recurrence of airway involvement in RP is common. Early diagnosis and prompt treatment are essential to reduce the risk of life-threatening airway collapse. The insertion of multiple stents in this patient has resulted in improving symptoms, spirometry, and a return to daily activities.