Fig. 1

1.1 The root system of an adult barley plant is mainly formed by postembryonic nodal roots. The white bar corresponds to 1 cm. 1.2 Two culms showing the node flanked by two internodes. The culm is enclosed by the leaf sheath that is the lower part of the leaf. The auricle is at the junction between the leaf sheath and the leaf blade. The white bar corresponds to 1 cm. 1.3 The top leaf of each tiller is called the flag leaf. Like other leaves, the flag leaf consists of a sheath and a blade as well as a ligule and an auricle at the junction between them. The junction between a barley spike and culm is called collar. The peduncle is the first (top) internode of the culm. The white bar corresponds to 1 cm. 1.4 The spike is the reproductive part of barley. A spike is composed of approximately 20 to 30 successive triplets of spikelets, which consist of one central and two lateral spikelets. In the two-rowed spikes shown in the figure, only the central spikelet has a fertile floret. The awns extend from the floret of the central spikelets and are usually as long as the spike. The top leaf is called flag leaf. The peduncle is the top (first) internode of the culm. The white bar corresponds to 5 cm. 1.5 The stem of the spike is called rachis, which consists of rachis nodes and rachis internodes. The spikelets are attached at the rachis nodes. The figure shows two-rowed barley where the lateral spikelets are sterile. A and B. All spikelets except the one triplet of spikelets attached at one rachis node have been removed. The flower is surrounded by the lemma, the palea and two glumes. The awn is an extension of the lemma. The palea is inside the lemma and closest to the rachis. C. The central spikelet has been removed. D. The rachis has been removed to show the palea side of the central spikelet with the rachilla attached slightly below the palea. The rachilla is a rudimentary branch of the rachis. The white bars correspond to 1 cm. 1.6 Close-up of three barley spikes, which are of the two-rowed type with sterile lateral spikelets. In the left spike, the lateral spikelets are very small. The central spikelet is fertile and has resulted in a mature seed in the right spike. The white bar corresponds to 1 cm. 1.7 A. The floret is composed of two leaf-like structures, the lemma and the palea. In the shown spike, all fertile flowers, except one, have been pollinated and therefore remain closed. In the open floret, the lemma and palea are separated exposing the cavity where the flower organs are kept. The bar corresponds to 1 cm. B. In the dissected floret, the upper rachis and the lemma have been removed to show the ovary with the featherlike stigmata and the three anthers (still not mature in the photo). The lodicules, situated between the palea and the lemma, can swell and thereby push away the lemma to facilitate exposure of the anthers and stigmata. In barley, usually this happens exclusively if self-pollination fails and capture of pollen from other florets is required (like shown in A). The bar corresponds to 1 mm. 1.8 A. Dissected anthers and ovary of a barley floret at the stage of pollination. Pollen can be seen dehiscing out from one anther. The stigma is dusty because it has received pollen. B. After a week the fertilized ovary has expanded longitudinally. The bar corresponds to 1 mm. 1.9 A barley grain one month after fertilization. A. The naked grain after removal of the lemma and palea. The embryo is facing the lemma side. B. The grain after removal of the seed-coat layer displaying the starch-containing endosperm. C. The embryo has been detached from the grain. The bar corresponds to 1 mm