Structure and Morphology of grasses

Jonathan UrraAitor Pinillos

This presentation is about grasses, their structure and morphology generaly, explaining the most importants parts of them, to demostrate the importance they have in our planet and in our agriculture productions.

INDEX 1- Introduction

2- Phases of the developmentI. Seedling developmentII. Germination and emergenceIII. Development of the root sistem

3-Plant structuresI. LeavesII. StemsIII. RootsIV. Inflorescence and floretsV. Flowering

4-Conclusions

INTRODUCTION

• Grasses are grouped in about 650 to 750 kinds of plants, which include 10.000 species.

• Grasses are the dominant vegetation on much of the world´s rangeland.

-All the cereal crops and

about 75% of the species

used as forages are grasses.

Characteristics:

-The grass family has the best range of adaptation to temperature and rainfall.

-Almost all are herbaceous.

-They vary widely in structure and growth habits.

INTRODUCTION

Classifications:

→ By photosynthesis pathway,

boot , C3 and C

4

- The grass family has the most

species with the C4, which is

characteristic of warm-season grasses.

-The C3 pathway is characteristic of

cool-season grasses.

→ By their life cycle:

-annuals

-perennials

SEEDLING DEVELOPMENT

• Shallow planting is critical to seedling:

– emerge and develop quickly before the reserves are used up when growth starts depending on photosynthesis.

• Seedling development is a critical factor in forages because:

- an adequate stand of plants needs to be established to be productive.

Similar for all grasses.

GERMINATION AND EMERGENCE1st root system

-Sign of germination --> emergence of the radical (primary root).-In seedling development up to five seminal roots may emerge

–very important early on for water uptake and nutrient absorption.

-The epicotyl elongates to emerge from the seed and agreement toward the soil surface.

-This root system is short-lived

2nd root system

→ Next, the mesocotyl ( between scutellar and coloptilar nodes) also elongates.

-In warm-season grasses very close to the soil surface.

DEVELOPMENT OF THE ROOT SYSTEM

→ The adventitious roots grow downward rapidly to provide water and minerals for the plant

• the seedling is considered established.

→ The improved water status facilitates adventitious rot development.

→ Adventitious roots rarely grow into dry soil.

PLANT STRUCTURES

-Growing plant development modifications that allow each species to be adapted to specific environmental conditions.

-This is obtained by several structures:

• Leaves• Stems• Roots• Inflorescence• Florets• Flowering

LEAVES

• Leaves are borne on the stems.

• Each leaf consists of a sheath, blade, ligule, and in some cases auricles.

• The sheath is green and photosynthetic.

STEMS

• Nonreproductive or vegetative tillers tend to be very short, consisting of node and unelongated internodes.

• When there is a flowering stimulus, (daylenght or temperature), the soot apex develops into the reproductive structure (inflorescence).

• Also there can be stoloniferus stems. They originate from auxiliary buds near soil level.

ROOTS

• Grasses have an adventitious fibrous root system.• New tiller develops adventitious roots from lower

nodes.• Each tiller begins like a new seedling.• The root system of grasses develops especially in the

upper soil horizons, – though it depends on the species.

• A lot of species differs in distribution of roots in the same soils.

INFLORESCENCE AND FLORETSInflorescence• Consists of a group or cluster of spikelets,

the basic reproductive unit.

Florets•The flowers are usually small and perfect, have a functional pistil and stamens.•Many forage grasses are cross-pollinated by the wind.

FLOWERING

Many grasses flower only once a year because they require:– a specific sequence of a short photoperiod, a cold period – and a long day for the shoot apexes to be differentiated and

develop into the inflorescence.

CONCLUSION

• We can say that plants consist of roots, stems, leaves and most have flowers and fruits at certain times of year.

• The most important aspects of the plants are studied. – morphology, structure and aspects related to their survival

mechanisms such as the flowering or the seedling development among others.

PERSONAL CONCLUSION

In our opinion this article is very interesting because the text refers to basic aspects of grasses.

We also believe that society should know a minimum about plants, since these are the basic human food grains.

For example: the cereals.

Finally to say that without the existence of plant, the life on this planet would be impossible.