|
В отличие от других злаков у риса имеется два последовательных колеоптильных листа. Первый - настоящий, бесхлорофилльный колеоптиль, второй - зеленый или первый лист без пластинки - шило. Все листья у риса, кроме двух первых, имеют влагалище, пластинку, язычок и ушки.
|
|
The root system of the rice plant has a very specific feature: the aerenchyma, a tissue with air-conducting cavities. The air reaches root aerenchyma via leaf stomae and stalks. Thus, the air is supplied not only to the root but also to all of the surrounding area, which favors the development of active soil microflora in rice fields. Rice's stalk is a straw with hollow internodes. Stalk length varies from 0.3 m (with dwarf varieties) to 6 m (with lowland rice). In most cases, it is 0.5 to 2 m long. The straw of Japanese rice subspecies is shorter than that of Indian rice subspecies. The number of nodes depends on the duration of the vegetation period (early-maturing varieties have about 10 internodes; late-maturing varieties have as many as 20). Unlike other gramineous crops, rice has two coleoptile leaves located one after another. The first one is a true achlorophyllous coleoptile. The second one is a green awl. All leaves of the rice plant, except for the first two, have a sheath, a lamella, a ligule and auricles. The leaf lamella is long and narrow (20 to 25 cm long and 1 to 2 cm wide). The uppermost leaf, called the standard, has a lamella which is shorter and wider than that of the other leaves. The bushing-out node forms 2 to 40 lateral shoots. Rice plants may also have branching-out shoots which develop from axillary leaf buds after rice plants have been submerged in water for a long time. Rice inflorescence is a panicle with 20 to 300 spikelets, which are 10 to 30 cm long. Panicles may be drooping, upright or intermediate. The degree to which rice plants shed their kernels depends on the structure of the spikelet joint where the spikelet is joined to the stem. Spikelets have small upper and lower lanceolate glumes. Their length usually is one third or one half that of the flowering glumes' length. Each spikelet has a single flower, which consists of lower and upper flowering glumes, two lodicules, six stamens and the pistil, which has two plumose stigmae. With aristate varieties, the lower flowering glume ends in an awn, which may be up to 15 cm long. The anthers are small (0.5 cm). Each one contains about 1000 pollen grains. Pollen grains are round, 35 to 38 micrometers in diameter. The ovary is formed by three carpels. Rice fruit is a caryopsis. After threshing, it remains inside lodicules, even though it is not accrete with them. The weight of rice glumes and lodicules accounts for 10 to 35% of its kernels' weight. 1000 kernels (with glumes)
|