Sucrose metabolism in the subtending leaf to cotton boll at different fruiting branch nodes and the relationship to boll weight

Abstract

Changes of sucrose metabolism in the subtending leaf to cotton (Gossypium hirsutum L.) boll at different fruiting branch nodes (FBN) were investigated. Two cotton cultivars, Kemian 1 and Sumian 15, were grown in the field at three planting dates in 2009 and 2011. Cotton planted on different dates but experiencing similar climatic factors flowered on the same date and had similar boll opening dates, but had different FBN. In the present study, boll weight and carbohydrate content were significantly affected by both flowering date (FD) and FBN. However, only cystolic fructose-1,6-bisphosphatase (cy-FBPase) and sucrose-phosphate synthase (SPS) activities of the sucrosemetabolizing enzymes were influenced significantly by FBN, and the influence of FBN was lower with delayed FD. In general, effects of FBN on boll weight and sucrose metabolism in the subtending leaf were higher at the optimal FD (13 August) than those at later FD (9 September 2009 and 2 September 2011), and total fruiting branches were used to characterize cotton physiological age in the current study. Sucrose transport capacity (Tn) and SPS in the subtending leaf had significantly positive correlations with boll weight at 17-24 days post anthesis (DPA), a crucial period when boll weight was significantly affected. In addition, higher SPS activity was favourable for sucrose export and boll weight during boll development.

Carbohydrate metabolism in the subtending leaf cross‐acclimates to waterlogging and elevated temperature stress and influences boll biomass in cotton (Gossypium hirsutum)

“…Sucrose and starch are two major end products of photosynthesis in cotton, where sucrose is the dominant carbohydrate utilized for translocation in the phloem from source to sink tissues (Koch ), and starch is temporarily stored in the chloroplasts for subsequent breakdown and conversion to sucrose in the cytosol during periods of high sink demand. In cotton, the subtending leaf is an important contributor to boll biomass because it supplies 60–87% of the carbohydrate requirement for the development of a mature cotton boll (Constable and Rawson , Wullschleger and Oosterhuis , Liu et al , Hu et al ). Therefore, the subtending leaf and its adjacent boll provide a unique model system to relate changes in carbon dynamics of a major source leaf to the growth of an economically important sink organ.…”

Effects of long‐term elevation of air temperature on sucrose metabolism in cotton leaves at different positions

“…Similarly, Liu, Chen, et al. () reported that SPS was the key enzyme in response to low temperature for the leaves growing on different fruiting branch positions.…”

“…Thus, the durations of exposure to high temperature were different among LSCB growing on FB 2–3 , FB 6–7 and FB 10–11 . Previous studies found that the responses of photosynthetic characteristics and sucrose metabolism of LSCB at FB 2–3 and FB 10–11 to low temperature were different (Liu, Chen, et al., ; Liu et al., ), because the leaves at FB 10–11 with young age had stronger tolerance to stress than the leaves at FB 2–3 with old age (Liu, Chen, et al., ). Our results also showed that the leaves at FB 2–3 and FB 6–7 were more sensitive to elevated temperature compared with the leaves at FB 10–11 , showing as that the changing amplitudes of SLW (Figure b), sucrose content (Figure b), starch content (Figure b), initial Rubisco activity (Figure b) and cy‐FBPase activity (Figure b) caused by the increased temperature were greater in LSCB growing on FB 2–3 and FB 6–7 relative to FB 10‐11 , which might be because the ambient temperature was lower for FB 10–11 .…”

“…4.1.1.39) activity and Rubisco activation state as described by Sharkey, Savitch, and Butz () and Liu, Chen, et al. () at room temperature (25°C).…”

“…3.1.3.11) was extracted according to Liu, Chen, et al. (). The extraction buffer contained 100 m m of Tris‐HCl (pH 8.2), 5% (v/v) of glycerine, 1 m m of EDTA and 15 m m of β‐mercaptoethanol.…”