Phloem anatomy predicts berry sugar accumulation across 13 wine-grape cultivars.

Introduction: Climate change is impacting the wine industry by accelerating ripening processes due to warming temperatures, especially in areas of significant grape production like California. Increasing temperatures accelerate the rate of sugar accumulation (measured in ⁰Brix) in grapes, however this presents a problem to wine makers as flavor profiles may need more time to develop properly. To alleviate the mismatch between sugar accumulation and flavor compounds, growers may sync vine cultivars with climates that are most amenable to their distinct growing conditions.

Coordination Between Phloem Loading and Structure Maintains Carbon Transport Under Drought.

Maintaining phloem transport under water stress is expected to be crucial to whole-plant drought tolerance, but the traits that benefit phloem function under drought are poorly understood. Nearly half of surveyed angiosperm species, including important crops, use sucrose transporter proteins to actively load sugar into the phloem. Plants can alter transporter abundance in response to stress, providing a potential mechanism for active-loading species to closely regulate phloem loading rates to avoid drought-induced reductions or failures in phloem transport.

Seasonal patterns of callose deposition and xylem embolism in five boreal deciduous tree species.

Premise: Phloem tissue allows for sugar transport along the entirety of a plant and, thus, is one of the most important anatomical structures related to growth. It is thought that the sugar-conducting sieve tube may overwinter and that its cells persist multiple seasons in deciduous trees. One possible overwintering strategy is to build up callose on phloem sieve plates to temporarily cease their function.

Super-Resolution Microscopy of Phloem Proteins.

Super-resolution microscopy bridges the gap between light and electron microscopy and gives new opportunities for the study of proteins that contribute to phloem function. The established super-resolution techniques are derived from fluorescence microscopy and depend on fluorescent dyes, proteins tagged with GFP variants or fluorochrome-decorated antibodies. Compared with confocal microscopy they improve the resolution between 2.

Computational models evaluating the impact of sieve plates and radial water exchange on phloem pressure gradients.

The sugar conducting phloem in angiosperms is a high resistance pathway made up of sieve elements bounded by sieve plates. The high resistance generated by sieve plates may be a trade-off for promoting quick sealing in the event of injury. However, previous modeling efforts have demonstrated a wide variation in the contribution of sieve plates towards total sieve tube resistance.

Are phloem sieve tubes leaky conduits supported by numerous aquaporins?

Premise Of The Study: Aquaporin membrane water channels have been previously identified in the phloem of angiosperms, but currently their cellular characterization is lacking, especially in tree species. Pinpointing the cellular location will help generate new hypotheses of how membrane water exchange facilitates sugar transport in plants.

Methods: We studied histological sections of balsam poplar ( L.

Effects of phyllotaxy on biomechanical properties of stems of Cercis occidentalis (Fabaceae).

Premise Of The Study: Phyllotaxy, the arrangement of leaves on a stem, may impact the mechanical properties of woody stems several years after the leaves have been shed. We explored mechanical properties of a plant with alternate distichous phyllotaxy, with a row of leaves produced on each side of the stem, to determine whether the nodes behave as spring-like joints.

Methods: Flexural stiffness of 1 cm diameter woody stems was measured in four directions with an Instron mechanical testing system; the xylem of the stems was then cut into node (former leaf junction) and nonnode segments for measurement of xylem density.