Factors Influencing Growth Factors Influencing Growth and Development of Plantsand Development of Plants

AS 90454AS 90454

Site SelectionSite Selection

Site Selection is determined by the Site Selection is determined by the requirements of the crop to be grown.requirements of the crop to be grown. Soil type and Soil type and ClimateClimate – including temperature, – including temperature,

GDDs, sunshine hours, rainfall and frost GDDs, sunshine hours, rainfall and frost susceptibility on the shoulders of the season.susceptibility on the shoulders of the season.

The micro-climate of the site is the result of the The micro-climate of the site is the result of the physical environmentphysical environment..

Specific Specific cultivarscultivars, ie Citrus spp. grafted onto P. , ie Citrus spp. grafted onto P. trifoliata are soil cold tolerant while cutting grown trifoliata are soil cold tolerant while cutting grown Citrus are not, sweetcorn requires a range in GDDs Citrus are not, sweetcorn requires a range in GDDs from 2200 for ‘Supersweet’ early season to 3000 from 2200 for ‘Supersweet’ early season to 3000 for full season cultivars, nectarines for full season cultivars, nectarines

Site EstablishmentSite Establishment

Orientation of permanent crops, ie North – Orientation of permanent crops, ie North – South for maximising sun exposure.South for maximising sun exposure.

Soil preparation, eg mounding prior to Soil preparation, eg mounding prior to planting for onions, potatoes and tomatoes.planting for onions, potatoes and tomatoes.

Base fertilisers (Nutrition) prior to planting.Base fertilisers (Nutrition) prior to planting. Irrigation system set up.Irrigation system set up. Soil pH, liming of soil.Soil pH, liming of soil.

Pests and DiseasesPests and Diseases Pests and diseases can influence the crop that can be Pests and diseases can influence the crop that can be

grown in a certain region, ie apples aren’t grown in grown in a certain region, ie apples aren’t grown in the Waikato and grapes are no longer commercially the Waikato and grapes are no longer commercially grown in West Auckland due to dampness of the grown in West Auckland due to dampness of the climates (botrytis). climates (botrytis).

New growth of all plants are very susceptible to pests New growth of all plants are very susceptible to pests and diseases.and diseases. Pests chew the tender tasty tips of plants restricting the Pests chew the tender tasty tips of plants restricting the

development of the plants and their ability to carry out development of the plants and their ability to carry out plant processes. plant processes.

Fungi such as mildew destroy apical buds.Fungi such as mildew destroy apical buds. Pests chew the plants providing an entry point for Pests chew the plants providing an entry point for

diseases which restricts the ability of the plant to grow diseases which restricts the ability of the plant to grow at an optimum rate.at an optimum rate.

Aphids sucking sap from cabbages

Grass grubs under turf

Aphids sucking the growing

shoot of a rose

Mildew on growing tip

InfectedClean

HormonesHormones

Plant hormones co-ordinate growth, Plant hormones co-ordinate growth, development and responses to environmental development and responses to environmental stimuli stimuli 5 types of hormone 5 types of hormone

AuxinAuxin GibberellinGibberellin CytokininCytokinin Abscisic acidAbscisic acid EthyleneEthylene