Influence of Shade on Stomatal Density, Leaf Size and Other Leaf Characteristics in the Major Tropical Root Crops, Tannia, Sweet Potato, Yam, Cassava and Taro

Abstract

S U M M A R YSince shading often occurs under normal growing conditions in various cropping systems (for example, intercropping, alley cropping), field experiments were carried out to determine the effects of shading on stomatal density, leaf size, leaf dry matter, and leaf lamina thickness in the major tropical root and tuber crops, tannia (Xanthosorna sa&ifooliurn), sweet potato (Zpornoea batatas), yam (Dioscorea esculenta), cassava (Manihot esculenta), and taro (Colocasia esculenta). Shading decreased stomatal density in the lower epidermis of tannia, sweet potato, yam and cassava, and in the upper epidermis also in tannia and sweet potato; the upper epidermis of yam and cassava were devoid of stomata. In contrast to the other species, taro under shade had an increased stomatal density in both the upper and lower epidermis, a finding which was confirmed in subsequent pot experiments. This response of taro was postulated as a possible manifestation of greater shade adaptation by the species.For all the species, shading generally resulted in the production of larger (in terms ofsurface area) but thinner leaves, with a decreased dry matter concentration. For the two species (yam and cassava) that had stomata only on the lower epidermis, normal sun-grown plants had about twice as many stomata per unit area of lower epidermis than did corresponding plants of the other three species. The agronomic and physiological significance of the findings are discussed.t Corresponding author

Testing the shade tolerance of selected crops under Parkia biglobosa (Jacq.) Benth. in an agroforestry parkland in Burkina Faso, West Africa

“…Johnston and Onwueme (1998) concluded that, among five major tropical tuber crops, cocoyam (Xanthosoma sagittifolium) and taro were particularly well adapted to shade. They also found that leaves of taro grown in shade were larger and thinner than when cultivated in full sun (Onwueme and Johnston 2000); in our study, taro grown under trees produced an greater number of leaves. It thus seems that C3 plant reactions to shade, to some degree, reflect their role in natural ecosystems.…”

Effect of shading by baobab (Adansonia digitata) and néré (Parkia biglobosa) on yields of millet (Pennisetum glaucum) and taro (Colocasia esculenta) in parkland systems in Burkina Faso, West Africa

“…This higher efficiency of taro, a C 3 photosynthesis pathway plant, in shade conditions can be explained by increasing leaf size, chlorophyll content per unit area and stomatal density in their leaves (Johnston and Onwueme 1998;Onwueme and Johnston 2000). Despite its photosynthetic efficiency in shaded conditions, taro plants growth may be affected when competing for nutrients and water with trees because of its high requirement for these growth resources (Bussel and Bonin 1998;Onwueme 1999).…”

Pertumbuhan dan produksi Okra merah (Abelmoschus esculentus L. Moench) pada dosis pupuk kompos serasah yang berbeda dan pemangkasan

“…Penelitian (Aliyu dkk., 2015) menyatakan bahwa proses pemangkasan dapat mempercepat proses pembungaan mencapai 50% lebih cepat dibandingkan dengan tanaman okra yang tidak dipangkas. Perlakuan pemangkasan dapat meminimalisir adanya Organisme Pengganggu Tanaman (OPT) (Iremiren, 1987).…”

“…Lingkar Batang Okra Merah pada Perlakuan Dosis Pemupukan Kompos Serasah yang Berbeda dan Pemangkasan Dosis pupuk kompos serasah (Kg N/ha) Pemangkasan Rata -rata Tidak dipangkas (P1) Dipangkas (P2) Iremiren (1987) pemangkasan sangat membantu tanaman dalam hal fotosintesis, karena pemangkasan pada pucuk tanaman membantu sinar matahari kesuluruh tanaman sehingga proses fotosintesis lebih maksimal. Pemangkasan membantu tanaman okra untuk merangsang produksi dan pengembangan daun agar aktivitas fotosintesis berlangsung secara efisien (Aliyu, 2015).…”